20. 02. 2026 Will Steen

What is Ocean circulation – and why does it matter?

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The Ocean is in constant motion.

Why does Ocean water move? Think about it. What do you need to move the Ocean? What is Ocean circulation, and why does it matter?

There are three drivers of Ocean currents.

The most visible driver of Ocean circulation is the wind. Big storms can whip up the waves, send them crashing into the rocks or barrelling over surfers. Waves can seem like the Ocean is moving a lot, but the water itself is moving mostly in a circular motion. We explain more in our article on the motion of the Ocean.

Prevailing winds can push the waters below in a consistent direction, such as the Gulf Stream, which does drive larger scale circulation. But usually, the wind is only moving the surface, and the Ocean is a lot deeper than the surface.

Next comes the tides. The moon, with a little help from the Sun, shifts the Ocean back and forth, changing sea level by metres in some places. The Bay of Fundy in Canada has the largest tidal range in the world, with almost 12m difference between high and low tide.

However, the tides are always changing. If tides were the only thing responsible for moving the water, then the same water would just be moved in and out. Out in the middle of the Ocean, the water would travel in a big vertical circle, like a giant Ferris wheel. To move the Ocean properly, we need something else.

The third driver of global Oceanic currents is more understated than crashing waves or retreating seas. It takes thousands of years to move water through the deep Ocean, from pole to equator to pole. It’s known as the Ocean Conveyor, or Thermohaline Circulation, and the polar Ocean is a focal point for its activity.

What moves the Ocean? Tides, wind and the thermohaline circulation explained.

Why is Ocean circulation important?

This movement of water is the heartbeat of the Ocean. It carries oxygen-rich waters to the depths, and where it returns to the surface (known as upwelling), the nutrients it brings with it create the richest waters on the planet.

The Ocean is also moving heat and carbon dioxide. It has absorbed approximately 25% of carbon dioxide emissions since the 1960s and over 90% of the excess heat trapped by greenhouse gases has been assimilated into our Ocean.

The Ocean can circulate and ‘drop off’ heat and carbon dioxide in the deep. If the circulation of the Ocean slows, the surface Ocean will get hotter and more acidic. With less circulation, the Ocean’s ability to trap and store two major drivers of climate change suffers.

Global Ocean Conveyor Belt — *IPCC via Smithsonian*

What is Thermohaline Circulation?

Thermohaline circulation is the slow, powerful pump behind Ocean circulation, the main driver of water movement in the Ocean. The name sounds complicated, but it tells us exactly what we are talking about.

Let’s break it down; Thermo-: we are talking about temperature; -haline about salinity, or saltiness. These two characteristics of seawater influence global climate and biological richness.

Temperature and saltiness have influence because they change how dense Ocean water is. Cold water is more dense than warm water, and salty water is more dense than freshwater. If water is denser, it will sink below less dense water.

These simple differences drive a slow, unseen conveyor belt from the poles to the equator and back again. It would take over 1,000 years for one drop of water to complete the whole Ocean circulation.

What will the cold, salty water now disappearing into the depths in the North Atlantic see when it re-surfaces in the Pacific in 3026?

Thermohaline circulation, explained by Ocean Generation.

Why are the Poles important for Ocean circulation?

If the poles are known for one thing, it is that they are cold. So cold in fact, they can chill seawater to the point of freezing (which happens around –1.8 to -2 degrees C / 28.76- 28.4 °F, lower than normal water due to the salt content).

When seawater freezes, it leaves its salt behind. As ice forms, the water left behind gets more salty, which lowers the temperature it will freeze at. More salt = lower freezing temperature. Very salty, very cold water is very dense, and will sink below other seawater.

This downward movement is known as downwelling. Downwelling pushes water along the depths and pulls water across the surface. This is the pump that moves the Ocean.

So begins the Ocean conveyor.

When does cold water become deadly?

Maybe you didn’t think water movement could be exciting. Maybe you haven’t heard of the finger of death.

We know as sea ice forms, it “spits out” salt, creating channels of brine (very salty water), which is colder than freezing. This brine travels down through channels in the ice, collects more salt and cools further.

It reaches the bottom of the ice super salty and super cold. It is so cold it freezes the sea water it touches below the ice, creating beautiful brinicles.

The brine is still too salty to freeze, so travels through the centre of the brinicle, growing it. If this is in a shallow area, the brine could reach the seabed before warming and diluting enough.

This ethereal beauty then becomes a sinister threat. It is so cold it freezes anything it touches. The sea stars, brittle stars, sea cucumbers living below the ice are at the mercy of the finger of death.

Most Ocean movement isn’t as dramatic as the finger of death, but it runs on the same mechanisms.

Finger of death, also known as brinicle — *BBC Earth*

Is Ocean circulation slowing down?

Ocean circulation relies on the cooling and sinking of water at the poles. As the release of greenhouse gases raises the temperature of our planet, especially at our poles, the water is not getting as cold.

We are seeing less sea ice form and the water has more fresh meltwater diluting it. The water is getting less cold, and less salty. Both mean the surface water is less dense, meaning it will sink less. Is the circulation of the Ocean slowing?

One way to study if it is slowing is by looking at how old the water is – older water means slower circulation.

How do you measure how old water is?

At the surface, chemicals and elements are constantly being exchanged between the air and the Ocean. Scientists can look at the chemical composition of the water, looking for indicators for when the water was last in contact with the surface.

Using Carbon-14 as a time marker

Carbon-14 is the usual way, a radioactive isotope of carbon that is used in radiocarbon dating methods from geology to archaeology. It’s also called carbon dating.

How does carbon dating work?

Carbon-14 is an isotope (type of atom) that decays slowly. Half of it will decay every 5700 years or so, known as the half-life.

Measuring the amounts of Carbon-14 can be like reading a timer. Carbon-14 is created naturally when cosmic rays hit our atmosphere, but in much larger amounts by nuclear weapons – levels doubled in the 1950s and 1960s.

This molecular ‘shadow’ has been found in marine animals in the Mariana Trench, showing just how far human impacts reach.

Track the amount of Carbon-14 and you can approximate when it was last in contact with the atmosphere, which gauges age.

Measuring human-made chemicals

Industrial chemicals such as CFC-12 and sulphur hexafluoride are other chemical clues used to age water. Chlorofluorocarbons (CFCs) were widely used in refrigerants and spray cans until they were identified as depleting the ozone layer.

Through global cooperation and effective science, the Montreal Protocol was introduced, preventing the use of CFCs and allowing the ozone layer to recover (learn more about international treaties here). The presence of CFCs can indicate exactly when that water is from.

Using oxygen to estimate water’s age

We can also look at the Apparent Oxygen Utilisation. The principle is that deep water can’t have oxygen added, so the older the water, the more oxygen will be used up from it, meaning older water has less oxygen.

Despite fluctuations caused by other Ocean movers (e.g. the wind), the waters in the deep North Atlantic are getting older, implying the water is not being replenished as quickly, and therefore that the circulation is slowing. The same is happening at the other pole.

The Ocean is made up of many different ‘bodies’ of water, with different characteristics and names. North Atlantic Deep Water is formed in the Arctic by cold, salty water sinking and flowing south. This water travels all the way to the Southern Ocean, where it meets another body of water.

Antarctic Bottom Water is formed at the South Pole and is the coldest and the densest of them all, the real powerhouse of Ocean circulation. But it is warming and there is less of it. The frost-fuelled engine is slowing.

What would a broken Ocean conveyor belt mean? Explained by Ocean Generation

What would a broken Ocean conveyor mean?

The Ocean would suffer.

Deep sea creatures relying on delivery of oxygen and nutrients would be left waiting, as deoxygenated areas grow. The same would happen for surface species that need the upwelling of nutrients from the deep.

If Ocean circulation stopped, there would be dead zones without oxygen in the deep and starved surfaces with no nutrients to support phytoplankton.

It would impact life on land too. If the circulation of the Ocean slows, global climates will shift. Increased storm intensity, more extreme weather patterns and changes to rainfall. Europe could face far cooler temperatures as the tropical water that brings warmth from the equator slows.

That is quite a big if, and fortunately, the Ocean is resilient. New work has shown circulation has slowed in the 2010s and 2020s by less than in the 2000s. This has been attributed to natural variability pushing against the human-caused weakening.

Every reduction in greenhouse gases, every degree of warming prevented, reduces the stress on our Poles and on our Ocean circulation. Keeping our poles cool keeps our Ocean moving.

Keeping our poles cool keeps our Ocean moving. Explained by Ocean Generation.

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Will Steen

From classroom to COP30: Questions from children to climate leaders about Ocean protection

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23. 01. 2026 Will Steen

Why krill matter: Krill fishing and conservation in the Southern Ocean

Why krill matter: fishing and conservation in the Southern Ocean.

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The Southern Ocean is one of the most remote places on the planet.

It was only in 1911 that the first human, Roald Amundsen, reached the South Pole. For context, the first powered aircraft, the Wright Flyer, took to the air in 1903. Humanity conquered the skies before it managed the southern continent. The waters here are cold, barely above freezing, yet full of life. These are some of the richest waters in the world.

The main character is just 6cm long. Antarctic krill (Euphausia superba) are small, shrimp-like crustaceans. They snack on the phytoplankton that thrives in the long hours of summer sunlight, trapping and storing similar amounts of carbon to seagrass and mangroves.

Their importance lies in their numbers: krill swarms are vast. The rust-coloured clouds are filled with billions of individuals and can be visible from space. They sustain most of the life around Antarctica. Penguins, seals, whales, fish and sharks all rely on this buffet: krill are a keystone species. More recently, people have joined the party.

Krill fishing has become a divisive topic, being featured in David Attenborough’s Ocean, calls to ban it being promoted at the United Nations Ocean Conference and some retailers withdrawing krill products from their shelves. Meanwhile, countries have applied to increase the catch limits and the amounts of krill being fished are higher than ever.

To understand where we are going, first we can look at where we have been. Why are krill important? What is our history in the Southern Ocean? What is our future?

Antarctic krill are small shrimp-like crustaceans. Posted by Ocean Generation. — *Photo credit: Brett Wilks*

How did we get here?

In 1775, Captain James Cook returned to England from a voyage around the world, in which he had searched for new lands. He found there wasn’t a new continent in the Pacific Ocean (at least not where one was predicted to be) and hypothesised on the existence of Antarctic land behind the ice (which he was correct about).

He had discovered some land on his travels: an island populated by seals and penguins, which was named ‘Isle of Georgia’ in honour of King George III of England. We know it now as South Georgia.

Sealing and whaling in the Southern Ocean

The element of Cook’s report that got attention was the abundance of fur seals on South Georgia and neighbouring islands. These pinnipeds were highly sought after, and between 1778 and 1822 an estimated 1.2 million fur seals were killed for their pelts. The species was almost completely wiped out on South Georgia and the islands.

The rise of industrial whaling then turned focus on to the waters of the Southern Ocean around South Georgia. Factory ships and explosive harpoons reduced the great whales to 18% of their original population. 5% of blue whales were left, and just 3% of humpback whales survived. When the last two whaling stations closed on South Georgia in 1965, 175,250 whales had been killed in those waters.

South Georgia, Antarctica. Posted by Ocean Generation.

When did krill fishing start?

Industrial fishing had been largely unmanaged, and everyone raced to benefit from the natural resources the Southern Ocean had to offer. One by one the marine species of the south had been targeted to great effect, and populations crashed. The focus then shifted to krill.

Industrial fishing for krill in the Southern Ocean increased through the 1960s and 1970s. As the species that formed the foundation of the ecosystem, the alarm bells rang, loud, at the prospect of the krill suffering the same fate as the seals and the whales.

Why are krill important?

Krill are a keystone species

The loss of krill would be disastrous for many different species. Whales, seals, penguins and fish are all krill predators. Less krill means less food for these species.

Southern Right whale mothers have shown a decrease in body condition over the past 40 years, suggesting ecological strain on an animal heavily reliant on Antarctic krill.

The population of krill has been linked with Adelie and chinstrap penguin numbers – when there is less krill, the penguin populations decrease.  And the fur seals, populations freshly rebounded from the hunting of the nineteenth century, are showing declines due to krill availability.

Without krill, life in the Southern Ocean could collapse.

To relay it in economic terms, krill are a vital piece of an ecosystem that provides, conservatively, $180 billion annually in ecosystem services – about 70% of New Zealands GDP in 2024.

Krill are climate champions

It isn’t just the animals in the Southern Ocean that depend on these. Krill are big players in the balancing of our atmosphere. They trap (sequester) a lot of carbon.

As phytoplankton photosynthesise, they take in carbon dioxide. When they are eaten by krill, the krill take on that carbon, some of which is then… dropped off. Krill faecal pellets (poo) alone are estimated to sequester 20 million tonnes of carbon dioxide per year. Depending on the price of carbon, this is worth between $4 and $46 billion.

Marshes, mangroves and sea grass are estimated to absorb 13, 24 and 44 million tonnes per year respectively, so when you add in the extras of krill moults (20 million tonnes) and migration (26 million tonnes), as the researchers say: “it is likely that Antarctic krill is amongst the world’s most important carbon-storing organisms.”

How is krill fishing managed in the Southern Ocean?

Those alarm bells over the fishing of krill led to the creation of the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR). It was formed in 1980 and entered force in 1982.

The CCAMLR is made up of 27 member states (as of January 2026), with a further 10 ‘Acceding’ states – that support but don’t contribute to the budget or take part in decision making.

The stated aim: to protect and conserve the ecosystem of the Southern Ocean. Article II of the convention states:

The objective of this Convention is the conservation of Antarctic marine living resources.
For the purposes of this Convention, the term ‘conservation’ includes rational use.

This captures a crucial distinction: fishing is an element of conservation, rather than an adversary.

How do you prevent overfishing?

Catch Limits

A general rule of thumb is that you can’t remove so much the population can’t sustain itself. That will vary with species – some animals reproduce a lot faster than others.

Understanding how much of a resource there is, is fundamental to managing it. This is one of the biggest obstacles in the Ocean: the water means you can’t just see (sea). In a field you can see how many cows there are, not true of a shoal of fish.

Acoustic surveying (using noise to find out what is there, like a bat) gives us estimates for the amount of krill. In short – a lot. We estimate there are over 300 million tonnes of Antarctic krill, roughly the same as the biomass of humans.

In the specific area targeted for krill fishing (known as Area 48), the biomass is estimated at 62 million tonnes (coincidentally, roughly the same mass as annual e-waste produced). So, CCAMLR adopted Conservation Measure 51-01. CM 51-01 set a trigger level at 1% of that biomass (620,000 tonnes) – when that is reached, all krill fishing stops, no questions asked. August 2025 was the first time this happened.

How acoustic surveying works: Explained by Ocean Generation.

Marine Protected Areas

Another tool in the toolbox is protected areas – designated places with specific rules. Choosing to avoid fishing in nursery areas, or places with high densities of predators, can ensure the health of the fishery.

The Southern Ocean is home to the first MPA on the high-seas (outside of the jurisdiction of any one country) and the largest. The South Orkney Islands Southern Shelf MPA was created in 2009, and is a no-take zone protecting penguin foraging areas.

The Ross Sea MPA was created in 2016 and is 2.09 million square kilometres, 72% of which is a no-take zone. The MPA has a controversial “sunset clause”, meaning the MPA will expire in 35 years unless renegotiated.

There are four other MPAs that have been proposed, but not yet agreed on.

Has the management of krill worked?

The krill fishery is one of the most closely managed in the world. Every single ship has an independent scientific observer on board to ensure catch and bycatch amounts are accurately reported. There is zero illegal, unreported or unregulated (known as IUU) fishing putting additional pressure on stocks.

Bycatch rates are very low. In 2004, after pressure to report bycatch, it was revealed 292 fur seals had been killed as bycatch. This prompted the fishery to adopt mitigation measures, and since 2010, 39 fur seals have been killed. This is alongside 7 humpback whales and 80 seabirds.

In many senses, this is a great success. Krill populations are stable and there have been little ecological impact from fishing. No other large-scale fishery in the world is as well-monitored, as efficient (in avoiding by catch) or conservative with catch limits. The industry refers to these points as support for increasing the limits.

What's next for the Southern Ocean? Posted by Ocean Generation.

It’s not just ‘how much’: Why location-specific catch limits matter

The numbers look excellent. However, the risk lies in local depletion. Taking 1% isn’t much unless you take it all from one place.

Penguins, seals and whales need the krill within reach. They can travel to find them, but the further they go, the more energy they spend to get there and the less far the meal will go.

To make an analogy:

It is like buying sweets. If you have £10 to spend on sweets, you could either buy lots of different types of sweets or spend all the money just on fudge. If you do the latter, Timmy from down the road might not get the fudge he wants because you bought it all.

To avoid krill fisheries removing the entire quota from one area and leave the local penguins hungry, CCAMLR introduced Conservation Measure 51-07 (CM 51-07). CM 51-07 divided the catch limits in area 48 into Subarea 48.1 (25%, 155,000t), 48.2 (45%, 279,000t), 48.3 (45%, 279,000t) and 48.4 (15%, 93,000t). It added another layer of protection to CM 51-01, but was a temporary measure with an expiry date, to incentivise agreement on long term measures.

In 2024, the CCAMLR failed to agree on new “move on” rules.  These would ensure fishing vessels leave an area once they have caught a certain amount, tackling the issues of local depletion. CM 51-07 expired without replacement at the end of the 2024 fishing season, leaving the krill fishery with only CM 51-01 (when  620,000 tonnes of krill is caught, fishing automatically stops) as guidance.

The CCAMLR currently doesn’t have any special measures to prevent the full quota being taken from the same place.

What is next in the Southern Ocean?

The krill fishery isn’t just dealing with changing policies, but also a changing Ocean.

The Southern Ocean is getting warmer.

The areas of sea ice coverage are decreasing, and a record low in 2023 was 1.02 million square kilometres less than the 1979-2022 average daily minimum. That is the same size as Egypt. The previous four years have seen the minimum sea ice extent drop below 2 million square kilometres.

Krill depend on sea ice. The changing amounts of ice impact the krill’s food – phytoplankton. As juveniles, they stay close for protection and graze off the algae that can grow on it. Less ice means less shelter and less food, which leads to a lot less krill before any fishing has happened. Maximum sea ice extents impact the following summer blooms of krill – more ice means more food and shelter for young krill, who then visibly blossom in the summer. 2025 had the third lowest sea ice maximum, behind only 2023 and 2024.

Since the 1970s, we have been seeing a reduction in the density of krill adults, and in the occurrence of very dense swarms around the Antarctic peninsula. These environmental changes also mean the krill are moving south – staying closer to the pole, where it is colder. This means that the northern ecosystems are losing access to their main food supply. It also means the areas divided up for krill fishing may not capture where the krill are anymore.

Conservation success: the return of the whales to Antarctica. Posted by Ocean Generation.

One of the biggest wins for nature and conservation is the return of the whales.

After population depletion by industrial whaling, whale populations are increasing to their historic levels. As whales return, the amount of krill they eat increases.

Acceptable krill catch limits from 20 year ago may no longer cater for the larger whale populations, which is why re-assessment is so important.

Even if the amounts of krill taken are acceptable, the fishing vessels can still affect the whales. The vessels disturb the whales and can spread krill swarms out more. This means that whales can spend more energy getting the same amount of food, which decreases their body condition and reduces their capacity to reproduce.

The situation gets more complicated when you combine the changes. Less krill is likely to disturb the recovery of whale populations.

Where do we stand on the future of krill?

The warming world and returning whales need to be factored into our management of krill fishing. But recent progress has been slow.

There is a lot of disagreement over the future of the krill fishery. In the meeting of the CCALMR in October 2025, Norway proposed a doubling of the catch limits for krill. At the same time, scientists are calling for a re-evaluation of the limits, as they are based on old data and assumptions. Meanwhile, concern about the exploitation of the Southern Ocean resulted in UK retailer Holland and Barrett withdrawing all krill products by April 2026.

The challenge of consensus

The CCAMLR operates on a consensus decision making model. Everyone has to agree before new measures can be introduced. New MPAs haven’t been agreed because one or two countries have blocked them on the grounds of a lack of scientific evidence and their right to fish for krill and other target species.

What have we learned from exploitation in the Southern Ocean?

There is a lot of hope to be found in the Southern Ocean. Fur seals were given protection in 1909, and their numbers have now recovered to over 3 million. Whaling stations on South Georgia are relics of the past, rusting microcosms of the industry they supported.

The CCAMLR is different to any other fishery. It has learned from previous mistakes and has made decisions based in robust science. A well-managed fishery will always be called too conservative, too limiting, too safe, because it will never reach the point of collapse or decline. So far, krill populations have remained steady, unaffected by us.

The Southern Ocean is changing, and so the fishery must change with it. Climate change, more whales and improved understanding of the ecosystem should all be considered in new fishery management.  There are three things to take from this:

We are capable of facilitating the recovery of the Ocean.
The Southern Ocean, and its krill, are facing new challenges.
We all benefit from the Southern Ocean, and its krill, flourishing.

Krill are small but mighty. They fuel giants and balance our climate. The continuing battle to protect them demonstrates how far we have come. We can understand better than ever the benefits this tiny crustacean imparts as a part of its ecosystem.

We don’t have all the answers, but the progress is reassuring. A relationship with the Ocean that is based in our understanding of the impacts of our actions will be much more productive than one based on the potential profits.

Krill are not the impressive, charismatic Ocean animals that whales and penguins are. But if we fail krill, we stand to lose the rest. Krill can be the species that marks a new chapter in our relationship with the Ocean – one in which we work with our Ocean rather than at the cost of it.

What have we learned from exploitation in the Southern Ocean?

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Will Steen

From classroom to COP30: Questions from children to climate leaders about Ocean protection

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15. 01. 2026 Will Steen

Narwhals and Unicorns: How the magic of the Arctic has changed

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Are unicorns real? Look to the Arctic Ocean.

Under a clear blue sky, icebergs silently sparkle as they float in the Ocean, occasionally nudging each other. The water between them is a deep blue and still, undisturbed. Until a twisted ivory lance pierces the air, sliding out of the water inch by inch until two metres of tusk are followed by a mottled grey head. The head directs the tusk down again, exhales through the nostrils on top and takes a deep breath, slipping into the frigid waters.

Maybe not quite how you would picture seeing your first unicorn.

Except there’s some bad news. Unicorns aren’t real. We are as disappointed as you are; the closest we can come to a unicorn is a whale that lives in the Ocean: narwhals.

But there was a time not so long ago that people believed the unicorn existed.

Why did people believe unicorns existed?

In the first half of fourth century BC the Greek physician Ctesias provided the first description of a unicorn. He outlined an Indian wild ass (a horse-like animal) with a crimson head and a tri-coloured horn about 28 inches long. He wrote that powdered unicorn horn acted as an antidote to deadly poisons.

Aelian, a Roman writer in 200 AD fleshed out the description and noted that only noblemen could afford the horns, they were so expensive.

Early Christianity adopted the unicorn as a symbol of Christ, with the horn as a symbol of the cross of Christ. Through the belief in protection for the self and the soul, the unicorn horn – known as alicorn – became a highly sought after asset.

Unicorn horns were symbols of wealth and power, often displayed in positions of prominence on banquet tables. It was thought that the horn would bubble if dipped in a poisoned chalice, saving the wielder – a popular tool in the medieval banquet hall.

At the peak of its popularity, a complete horn was worth 20 times its weight in gold*, and even powdered horn once cost ten times.

Where did yhe unicorn myth come from? Explained by Ocean Generation, leaders in Ocean education. — *Illustration from the book The history of four-footed beasts and serpents by Edward Topsell.*

Unicorn horns were sought after by nobles, kings and religious leaders in Europe:

For example, Lorenzo de Medici had one valued at 6,000 gold florins (around $1 million). Ivan the Terrible was reported to have paid 10,000 marks for one, and called for it to be brought to him on his deathbed. Martin Luther was said to have been saved from an assassination attempt by powdered unicorn horn, and had a spoon made from the magical substance.

Such a powerful tool befits a queen, and on hearing that Mary Queen of Scots was using unicorn horn to test her food for poison, Elizabeth I offered a handsome reward for another. Privateer and Arctic explorer Martin Frobisher (or Humphrey Gilbert, both were on the expedition, but different sources credit them) found a narwhal washed ashore in Canada and gifted it to the queen. She was enamoured with it and covered it in jewels. It was said to be valued at £10,000*, approximately £3 million in modern terms. She also handed a gilted and bejewelled unicorn horn drinking vessel down to James I.

Even the Pope, one of the main focal points of power and wealth at the time, was involved. Pope Clement VII gifted Francis I of France a unicorn horn on a silver stand.

In the 1660s, King Frederick III ordered the building of a coronation chair. This chair was made using several unicorn horns and served as the centrepiece of Danish coronations until 1840.

But as we know, unicorns aren’t real. Where are these horns coming from?

Unicorn horns were sought after by European nobles. Posted by Ocean Generation. — *The Trustees and Factor and Commissioner of the Walker Trust / National Museums Scotland*

Where did tales of unicorn horns come from?

Most of the Roman and Greek accounts of unicorns were likely based on stories from travellers coming across rhinoceros in India and Africa. But after these initial accounts describing the horn as straight, Christian art from about 1200 changed its view of the unicorn.

Unicorns now had spiralled horns. There is only one animal that possesses a straight, spiralling ‘horn’ – the narwhal (Monodon monceros). And it isn’t a horn at all, but a tooth.

Christian art from about 1200 depicted unicorns with spiralled horns.

What you need to know about narwhals: unicorns of the sea

The name comes from the Old Norse nárhval, meaning corpse whale. Narwhals have mottled grey skin not dissimilar to rotting flesh and like to lounge at the surface – behaviour known as logging. Combine the two and you can understand why the Viking explorers named them.

Narwhals are homebodies. They have ‘high site fidelity’ – meaning they stick to the places they like and will go back to their favourite spots. They can be found in the Canadian Arctic, through to East Greenland, Svalbard and the western Russian Arctic.

What is a narwhal’s ‘horn’?

The ‘horn’ of a narwhal is one (or in rare cases two) of the incisors, so is a tusk rather than a horn at all. All narwhals have two tusks embedded in their top lip.

Most commonly, males in their 2^ndor 3^rd year will have the front left tusk erupt through their top lip, growing with age to reach 1.5-2.5m long. Around 3% of narwhals are anomalies, with some females growing tusks, some males growing two or none at all. Double tusks in narwhals are about as common as an extra finger in humans.

What do narwhals use their tusk for?

The use of the tusk is still under debate.

The first theories were that narwhal tusks were used for piercing prey or breaking up ice to make breathing holes. Observers supposed they could also function as a defensive mechanism or a cooling system. However, these theories are either discredited or unproven. The real uses are even more spectacular.

What do narwhals use their tusks for? Explained by Ocean Generation. — *NIST/Glenn Williams*

Dental Displays

Studies suggest that narwhal tusks are sexually selected. Male narwhals will use their tusk as a display feature in competition with each other, and bigger is better. The size of the tusk has been shown to positively correlate with teste size – so could be an easy indicator for the females to see which males are most fertile. Sometimes, size does matter.

Where males with similar tusks meet, they may fight – male narwhals show far more scarring on their heads than juvenile and female narwhals and 40-60% have broken tusks, but this hasn’t ever been observed.

What is sexual selection?
Sexual selection is a special type of natural selection, where traits that increase reproduction will be passed on.

Fish Fencers

But it isn’t just for showing or skirmishing. Using drones to study the narwhals’ behaviour, researchers saw the tusks in action. They could use the tusk to guide the fish, chasing it. They even saw the tusk being used, as a thresher shark uses its tail, to hit the fish, stunning it ready for eating. The scientists involved think there could even have been an element of play.

Temperature Taster

In 2014, we discovered that a narwhal tusk was full of holes and nerves. This could mean that it can operate as a water sensing tool for the narwhal, and they can ‘feel’ changes in water saltiness (salinity) and temperature. They show elevated heart rate when the horn is exposed to very salty water and fresh water, suggesting they can detect it.

‘Feeling’ your surroundings can be very useful for navigation, when diving deep and moving between their favourite spots. It could also save their lives. Seawater freezing depends on the temperature and salinity of the water – saltier water needs to be colder before it freezes. By knowing the temperature and salinity of the water they are in, they are detecting when the water is likely to freeze, trapping them from the air to breathe.

This could also be used in hunting – those narwhals we’ve seen using their tusks to ‘chase’ fish? They could be using their swirly sensor to detect the fishes’ movements through pressure changes in the water, even faster than they can see them

Narwhals are nicknamed the unicorns of the sea. Posted by Ocean Generation. — *phys.org*

Are narwhals magic?

So, we have a tooth that helps guide them through the icy waters like Rudolph’s nose, zero in on prey like a laser guided missile and show off their suitability to be a parent.

A narwhal’s tusk could enable them to tell when ice is going to form and find prey hiding in the dark as they can dive over a kilometre (3,281 ft) down, where no light can reach.

Unicorns might not be real, but this all sounds like magic.

Does something lose its magic just because we understand how it works? Whether it is magic or incredible biology, the enchantment of the narwhal is threatened by a changing world.

How is the narwhals’ world changing?

The opinions and doting of nobles across Europe and the world meant nothing to the narwhal. After years of hunting operations, narwhals are now enduring other changes, this time in their home. Climate change, caused primarily by the human burning of fossil fuels, is hitting the polar regions, where narwhals live, the hardest.

The Arctic is warming faster than the rest of the world. This is known as polar or Arctic amplification (AA). AA has resulted in the Arctic warming by as much as four times the rest of the globe. Since 2006, the air temperature in autumn and winter has increased by more than twice the global average.

Narwhals live around the Arctic Ocean. Posted by Ocean Generation. — https://doi.org/10.1016/j.marpol.2013.10.005

Why do narwhals live in the Arctic Ocean?

Narwhals like it cold. Where the sea is warmer, there are less narwhals. Why? This could be to do with their prey – one of their favourites, cod, are known to grow better in water temperatures of less than 2 degrees.

It could also be to do with their supreme adaptions for the coldest places on the planet – they may overheat at higher temperatures. No one wants to be wearing a thick winter coat on a hot summer’s day.

How is climate change impacting narwhals?

There is less ice. November 30 2025 saw the lowest area of Arctic ice on that date on record. The previous 20 years have given us the 20^th lowest sea ice minimums on record, and there is 95% less old sea ice (over 4 years old) than the average from 1979-2004.

Ice is an important part of the lives of every animal living in the polar seas. The loss of sea ice has been shown to change the diet of the narwhal as they can’t eat ice-based (known as sympagic) prey, so they eat more open-water (pelagic) species instead.

Through burning coal and mining for gold, humans have increased the amount of mercury in the environment. Less ice means there is more bioavailable mercury. The result: the narwhals are exposed to more mercury. Increased mercury levels can impact the reproduction and immune systems of narwhals. How do we know this? Through analysing narwhal tusks, which give us an insight into their life history. The magic tusks are whispering to us.

The reducing ice also means there is more human activity. We are a noisy bunch, and narwhals have shown to be sensitive to ship noise, reducing their deep dives for food (and given they are inefficient in their dive success, they need them).

The Arctic Region is warming four times faster than the rest of the world.

How are we preserving the magic of the Arctic?

Narwhal hunting is monitored and almost every whale caught is for the subsidence of the indigenous Inuit people. The population is difficult to track, especially without a reliable baseline. However, the International Union for the Conservation of Nature assessed the population in 2017 and shifted the status from Near Threatened to Least Concern. The narwhal is doing well so far.

The isolation of the Arctic and the changing attitude towards cetaceans means the narwhal hasn’t had to deal with a multitude of human pressures. But more than ever, those pressures are finding them where they log.

Research will continue to develop quieter boats, and policy will increase protected areas. The narwhal is one example of a bit of remote magic we are trying to keep.

Climate change is being tackled head on, with an energy transition in full flow, electric vehicles going from strength to strength and global emission increases are slowing. We will be the generation to see the transition to human flourishing not coming at the cost of our natural world, for the first time.

But within this, driving this, is being able to see the magic of the unicorn, not as a made-up money-making monopoly manufacture, but in the reality of the narwhal and its beautiful, magical tooth. See the magic, spread the magic – that is what will lead to us protecting the magic.

*Wexler, P. (2017). Toxicology in the Middle Ages and Renaissance. Academic Press.
Cover image by Проектный офис Нарвал

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Will Steen

From classroom to COP30: Questions from children to climate leaders about Ocean protection

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25. 11. 2025 Will Steen

Marine discoveries and Ocean wins in 2025

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What were the Ocean wins in 2025?

The past year has seen some amazing developments in our understanding of and our relationship with the Ocean. We’re unpacking: what Ocean discoveries have we made, what Ocean protection have we brought in and what Ocean recovery have we seen in 2025?

Jump to:

What Ocean discoveries happened in 2025?

New clownfish related discoveries

Over the course of 2025, there have been a series of discoveries centred around the clownfish, made famous by Nemo and Marlin in Finding Nemo (see our scientific analysis of the film here).

How does the clownfish avoid being stung by the anemone?

By having lower levels of sialic acid on their skin, clownfish avoid being stung by anemones. Sialic acid can be found on the outer surface of most animals – it is important in cell-to cell communication and immune response. The nematocysts (stinging cells) of the anemone have a special trigger, to avoid the anemone constantly stinging itself. Researchers found the fish that can live in an anemone have low levels of sialic acid, to ‘hide’ from the anemone, and avoid triggering its stings.

We discovered that the relationship between clownfish and anemone isn’t as one-sided as it may seem.

Anemonefish have been observed feeding their anemones large food they can’t eat, or extra food after they have eaten their fill. This has also been shown to increase how fast anemones grow.

Why do fish carry anemones around in their mouths?

Clownfish aren’t the only ones buddying up with anemones. Several species of fish have been photographed holding larval (baby/ juvenile) anemones in their mouths.

The assumption is that they are effectively arming themselves with marine (live) pepper spray. Predators can be warded off with a nasty sting. The anemones also benefit, as the young fish can swim and be swept much further than the anemone would normally reach.

The young fish have a predator deterrent, and the anemone gets a lift to a new neighbourhood.

Why do fish carry anemones in their mouths? Posted by Ocean Generation, leaders in Ocean education. — *Picture credit: Afonso et al. 2025, J Fish Biol. DOI: 10.1111/jfb.70214*

What new Ocean species were discovered in 2025?

A new species of manta ray was distinguished in 2025, adding a third species to the manta ray family.

Until 2009, there was only one species of manta ray. In a study focussed on morphological characterisation, analysis of colour, teeth and other traits differentiated the reef and Oceanic manta rays.

In 2025, after years of speculation, it was confirmed that there was a third species of manta.

Lead author of the study identifying the Oceanic and reef manta species, Dr. Andrea Marshall, had theorised a third species after diving in the Atlantic Ocean with manta rays she didn’t recognise. Years of study, including the description of a type specimen and genetic analysis, have confirmed her hypothesis: a third species of manta ray exists.

New species of manta ray was described in 2025. — *Picture credit: Leo Francini a; Guy Stevens/ Manta Trust b, e; Rawany Porfilho c; Mauricio Andrade d; and Nayara Bucair f*

Facts about the newly discovered manta ray:

Mobula yarae, more commonly known as the Atlantic manta ray, are named after Yara, the ‘mother of waters’ from Indigenous Brazilian mythology.

Telling them apart from other manta rays starts with size: they reach an approximate size of 6m across, sitting between the Oceanic and reef manta in size. A ‘V’ shaped white shoulder patch, lighter colouration around the mouth and eyes and dark spots confined to the belly rather than between gill slits are the key identifying features.

The Ocean Census announced that it has facilitated the discovery of 909 new Ocean species.

The program, in its second year of running, hopes to fast-track Ocean discovery, and so far has increased the annual speed of species discovery by 38%.

A new kind of shark discovered

Sticking with our elasmobranchs (cartilaginous fish that include sharks, skates, and rays), a new kind of guitar shark was discovered off the coasts of Mozambique and Tanzania. It joins 37 other guitar sharks in one of the most threatened vertebrate families, with two thirds of them threatened.

New species of snailfish in the deep-sea

Looking deeper in the Ocean, a new species of snailfish was discovered 3,263m deep.

The suitably named ‘bumpy snailfish’ is only two to three inches long and was one of three new snailfish species found on the expedition led by the Monterey Bay Aquarium Research Institute.

There are over 400 species of snailfish, and the family holds the record for the deepest dwelling fish, with one found 8,338m deep.

New Ocean species discovered in 2025. Posted by Ocean Generation. — Picture credit: Guitar shark: Sergey Bogorodsky / The Nippon Foundation-Nekton Ocean Census, Snailfish: MBARI, Sponge: The Nippon Foundation-Nekton Ocean Census Schmidt Ocean Institute © 2025 Coral: Xu et al., Zootaxa, 2025

Meet a newly discovered sea sponge: the Death-ball sponge

As one of the more notably named, the death-ball sponge (Chondrocladia sp. nov.) received a lot of press.

Where most sponges unobtrusively filter the water for food (ensuring highly efficient nutrient circulation where there isn’t much to go round), this new species has a number of ‘balls’ covered in tiny hooks to trap their prey.

New deep-sea discoveries with celebrity nicknames

There were a couple of famous characters whose semblances were discovered in the deep Ocean.

A deep-sea coral first spotted in 2006, but formally described this year, was given the name Iridogorgia chewbacca, due to its long hairy branches.
An iridescent scale worm found in the freezing waters of Antarctica was given the nickname ‘Elvis-worm’, its sparkling scales shimmering in the deep like the sequins of the King of Rock and Rolls’ jackets in Las Vegas
And a bonus one (not a new species): the colossal squid was caught on camera in its natural habitat for the very first time. This one wasn’t all that colossal: it was a juvenile just 30cm long.

What Ocean protection happened in 2025?

60 countries ratified The High Seas Treaty in 2025

In September, the Agreement on the Conservation and Sustainable Use of Marine Biological Diversity of Areas beyond National Jurisdiction reached 60 ratifications, the milestone required to start the countdown to it becoming legally binding. From 17January 2026 the agreement, also known as the biodiversity beyond national jurisdiction (BBNJ) or High Seas Treaty, will enter force.

Read more about the High Seas Treaty here.

The High Seas Treaty will come into force in January 2026. Posted by Ocean Generation.

Many countries have been protecting the Ocean off their coastlines in 2025.

Countries haven’t been hanging about, waiting for the High Seas Treaty, they have been getting on with Ocean protection in their own patches.

Marine Protected Area, or MPA, is a general term for an area of Ocean in which human activities are managed or limited to protect the marine world. Depending on what they are aiming to protect, they can have different rules. Some will allow sustainable fishing and recreation; others may be no-take zones where no fishing is allowed.

What is the largest marine protected area in the world?

French Polynesia announced the creation of the world’s largest marine protected area in 2025. The protection of their entire exclusive economic zone, an area of 4.8 million square kilometres, now includes 1.1 million square kilometres of highly protected waters.

An exclusive economic zone is the area of Ocean extending up to 200 miles from the coast of each country, in which they have the rights to explore and utilise any marine resources.

A huge no-fishing zone has been expanded in the South Atlantic Ocean:

For Marine Protected Areas (MPAs) around South Georgia and the South Sandwich Islands (not where sandwiches were invented), the ‘no take zones’ where no fishing can occur have been expanded to over 470,000km2, 38% of the MPA. This is to help protect the migration routes of humpback whales.

How whales are being protected in marine sanctuaries:

That isn’t the only help we’ve given our whale friends. In October, a proposal for a huge marine sanctuary in the North Atlantic was approved. Macaronesia is an area including the Azores, Madeira, the Canary Islands and the Cabo Verde islands. It’s rich in marine biodiversity, hosting 32 different species of cetacean. (Cetaceans include whales, dolphins and porpoises.)

The new marine sanctuary will hope to protect the Ocean from increasing pressures of boat traffic, underwater noise, industrial fishing and future threats such as deep-sea mining.

Do marine protected areas really help protect the Ocean?

In a little win of its own, a research paper was published this year that showed that fully and highly protected marine areas do work.

There have been concerns that enforcement around MPAs isn’t feasible, any fishing vessels can just ‘go dark’ – turn off their identification systems and continue poaching.

But analysis using artificial intelligence and satellite imagery has shown very little industrial fishing activity in highly protected MPAs. Conversely, there was substantial activity in MPAs with low protection.

We’re protecting more of the Ocean, and it is working.

What is the EU Ocean Pact?

On money, the European Commission launched a unified framework for EU Ocean policy in 2025, backed by a €1 billion investment in the Ocean, with six priority areas including: habitat restoration, decarbonisation of maritime sectors, blue economy competitiveness, coastal/island community support, Ocean diplomacy and innovation.

Progress on cutting shipping emissions

Member States of the International Maritime Organisation agreed a global standard for decarbonising shipping: fuel‑intensity reductions, global emissions pricing for ships, and a fund for low/zero‑emission marine fuels.

The agreement was agreed but not formally signed, as in a meeting in October 2025 delegations from Saudi Arabia and the United States lobbied for a delay.

This is half a win this year and will hopefully be a full win for our Ocean in 2026, in a sector that accounts for around 11% of global emissions in transport.

2025 saw progress cutting emissions from the shipping industry

What Ocean recovery have we seen in 2025?

Are whale populations bouncing back?

In a paper published towards the end of 2024 that examined historic databases on whales, it was suggested that we underestimate the longevity of whales by some distance.

How old do whales get?

Our estimates for the average age of whales were first shaken in 1979, when Japanese whalers found individual blue and fin whales that were 110 and 114 years old respectively. Prior to this, we understood these animals to live to 70 years.

This 2024 paper attributed the lower perceived longevity to our success in whaling. Whales weren’t living as long because we were hunting them.

But the world is changing. Whaling was made illegal in 1987, and populations have shown promising signs of recovery. Over the course of 2025 there were several markers of a better world for whales, and hints of the future we are creating for them.

The Atlantic Northern Right Whale, one of the most endangered whales, has enjoyed an increase in population, up 8 individuals to 384 whales. This is off the back of a decade in which the population declined by 25% between 2010 and 2020 due to ship strikes and entanglement.

2025 saw the cancellation of the Icelandic fin whale season, meaning once again no fin whales were killed due to an unfavourable market, marked by diminishing demand for whale products and rising costs.

Atlantic Northern Right Whale population is bouncing back. — *Picture credit: Whale and Dolphin Conservation*

Who is ‘crush’ing it? Green turtles are no longer endangered.

It’s a good time to be a green turtle (Chelonia mydas). The species, made famous by Crush and Squirt in Finding Nemo, has been upgraded on the International Union for the Conservation of Nature (IUCN) Red List, from Endangered to Least Concern.

To best help them, we had to understand what was hurting them. Green turtles (and other sea turtle species) have long been hunted for their meat and their eggs, so legally protecting them was a good first step.

When did we start protecting sea turtles?

Legal protections started coming in in the second half of the 20^th century, with bans such as that on Aldabra Atoll in 1968 safeguarding turtle mothers and their eggs. Since that ban, green turtle egg clutches have increased 410−665%.

Even without the pressures of hunting, turtles still faced a struggle, becoming the poster of plastic pollution and entanglement in fishing gear, and facing the realities of a changing Ocean.

But conservation efforts have continued. Excluder devices (devices designed to prevent bycatch) have been implemented on fishing gear to avoid entanglement. Nesting beaches have been protected from light pollution that could lead hatchlings away from the Ocean, or plastic pollution that could tangle or choke them. Turtle hatchlings have been released at sea to give the population a boost.

Green turtle numbers are now up 28% compared to the 1970s.

Some sub-populations are still struggling and need help, but it shows us, again, that the Ocean has a great capacity to recover when we allow it.

“The ongoing global recovery of the green turtle is a powerful example of what coordinated global conservation over decades can achieve to stabilise and even restore populations of long-lived marine species,” – Roderic Mast, co-chair of IUCN’s Species Survival Commission Marine Turtle Specialist Group.

Green sea turtles are no longer endangered. Posted by Ocean Generation.

Dam Good News for salmon

In 1878, a lamp turned on. In itself, not a remarkable event, but this lamp was special. It was powered by water.

Cragside House in Northumberland, England, saw the birth of hydroelectric power. Within ten years, hundreds of hydropower stations were running around the world. It remains the third largest source of electricity globally, behind coal and gas. Until 2004, it represented over 90% of the world’s electricity generated by renewables and is still over 50%.*

Benefits of hydropower

Our World in Data compiles the data to examine its benefits. Hydropower is incredibly safe, with the 1.3 deaths per terawatt hour of electricity produced far lower than coal’s 24.6, and almost all from a single event: the Banqiao Dam Failure in China in 1975, which killed 171,000.

Hydropower is very clean, producing an average of 24 tonnes of CO2 equivalent per gigawatt hour, compared to coal which produces 970 tonnes. A world without hydropower would likely be a world that had burned more fossil fuels.

Disadvantages of hydropower

However, hydropower isn’t all turbines and waterfalls – it comes with its limitations. It’s expensive, especially in upfront cost. It also has an environmental impact beyond carbon emissions.

Huge dams create reservoirs, flooding land and cutting off rivers. Cutting off the rivers can lead to drought or famine downstream. Reservoirs can emit greenhouse gases by creating large areas of stagnant water full of decomposing material. As solar and wind have become far cheaper and more accessible, there is less need for the large projects.

Salmon, returning home after 100 years:

In 2023, the world’s biggest dam removal project re-opened the Klamath river in California and Oregon.

The project was initiated by local populations after 30-70,000 salmon died below the dams in 2002 due to low flow, the costs of maintenance and repair coupled with environmental costs and the reservoir’s proclivity to harmful algal blooms.

This year, the salmon returned to the Chiloquin Basin for the first time in over 100 years.

“A hundred and fifteen years that they haven’t been here, and they still have that GPS unit inside of them. It’s truly an awesome feat if you think about the gauntlet they had to go through.” said the visibly giddy Klamath Tribal Chair William Ray, Jr.

Salmon returned to a river in California after the removal of a dam.

This is a story mirrored elsewhere in the world too – salmon returned to the river Don in England for the first time in two centuries this year.

As we explored in some articles earlier in 2025, rivers and residents like salmon are vital in connecting different ecosystems.

Hydropower can prevent the salmon migrating and breeding in their ancestral waters and poison the rivers they grow up in. Losing that connection impacts the people and life all along the river.

We need energy to reinforce our high quality of life. That used to come at the cost of our natural environment. However, we are more aware of that impact, and we are getting far better at diminishing it. Stories like this are sprinkled with glimpses of a bright future, in which humans can flourish with nature.

This pattern – discovery igniting protection, protection enabling recovery – reflects how our relationship with nature has evolved over decades, not just this year.

The Ocean wins of 2025 demonstrate a shift in our relationship: we are learning to value and safeguard our seas, and in return, the Ocean is proving its remarkable capacity to heal.

In ten years, we hope stories of recovery and flourishing will dominate the narrative, as the need for more protection fades.

Discovery is good too; it will always be fun to hear about new death-ball sponges and bumpy snailfish.

* Energy Institute – Statistical Review of World Energy (2025)

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Will Steen

From classroom to COP30: Questions from children to climate leaders about Ocean protection

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16. 10. 2025 Will Steen

What deep-sea creature is the best Halloween costume?

Five deep sea creatures that make perfect Halloween costumes. Posted by Ocean Generation.

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Trying to avoid spending money on a new Halloween costume you’ll only wear once?

Trying to be environmentally friendly? Just got a last-minute invite to an Ocean-themed costume party? Just love the deep sea? We got you. These deep-sea creature costumes should help you bring the Ocean to the Halloween party.

For the main event: dress up as an anglerfish

Anglerfish female and parasitic male. Posted by Ocean Generation. — *Photo by Edith A. Widder*

A classic. Anglerfish are the posterchild for the deep sea. Who hasn’t dreamt of these creatures lurking in the depths, with huge teeth and a glowing orb of light to draw you in until it is too late to escape.

Finding Nemo put this fish on the map for many of us (but it wasn’t completely accurate – see here).

We are using anglerfish liberally here: there are many different animals that could be referred to as anglerfish, but we are talking about deep-sea species from the Ceratioidei family.

The name means horn bearers, referring to the modified dorsal spine that for many species has a lit up lure at the end.   Anglerfish host bacteria in their lure to generate light. This attracts fish, shrimp or squid close enough for the anglerfish to suck into its mouth, which is very big for their body.

Eyes too big for their stomach? Not likely for the anglerfish. They have extendable stomachs that can hold fish twice their size (useful if you aren’t sure when your next meal will swim along).

The main point to hit in your costume is the lure – the esca. Face paint for some big teeth would certainly add to the look.

What you need for the anglerfish Halloween costume:

Light source (headtorch, LED lights etc.)
Something to hang it off
Hat
Black clothes

I have done this outfit before on very little notice, using toilet rolls as the illicium (the modified dorsal spine tipped by the esca). Other good options are repurposed clothes hangers or just a good-sized stick from outside. Attach your esca to your illicium (some glue, blue tac or tape), attach your illicium to your hat and away you go!

A battery pack on the back of the hat can act as a good counterweight to your lure.

Now just watch your work entrance everyone around you, tempting them closer. Too close, and they risk your teeth.

Optional extra: Add a parasitic male!

We aren’t telling you to invite your ex. But Anglerfish live in the deep Ocean, so when they get the chance for romance, they don’t let it pass.

The female anglerfish is far bigger than the male, who is little more than a sperm donor with a good sense of smell.

This size difference is most on show in Kroyer’s deep-sea anglerfish, Ceratias holboelli. Males can reach up to 1.3cm (while free-swimming), while the females are on average 77cm long.

When he finds a female, he bites her and doesn’t let go. Over time, he fuses with her, receiving nourishment in exchange for sperm. One female can have multiple males attached, and she can lay her eggs at her own leisure.

To add your parasitic male, just stick an empty loo roll in a sock and staple/attach it to yourself. The more the merrier!

For the witty one-liner: the cookiecutter shark

This is a true Halloween shark, with the old nickname “demon whale-biters”.

These little sharks gouge a circle of flesh out of animals, leaving bite marks as if cut out by a cookie cutter.

Whales and dolphins are often spotted with the strange circular wounds, multiple if they were unfortunate enough to come across a group of cookiecutters. One sei whale was found with 138 “cookies” cut out. Fortunately, these bitey biscuit bois are only half a metre long, so the damage they cause is limited.

The cookiecutter doesn’t need the dentist – rather than brushing their teeth, they lose the entire bottom row and usually swallow it with whatever meal they are enjoying (recycle some of the calcium).

What you need for the shark costume

What you need for a cookiecutter shark Halloween costume. Posted by Ocean Generation. — *Cookiecutter shark photo by Blue Planet Archive/Alamy*

A cookie cutter
Cardboard/card
A black scarf
Brown clothes
Optional: Chef hat

Sometimes simplicity is the way. Wear brown clothes, hang a cookiecutter around your neck and fashion a shark fin to attach somewhere, with the cardboard.

Add the black scarf around the neck, for the cookiecutters dark collar (this is one of the reasons they are also known as ‘cigar sharks’). If you want to make it a couple’s costume, dress your partner as a whale with some bloody circles on them!

Optional extra: glowing belly!

Cookie cutters have photophores on their belly, to camouflage them from predators and prey by matching the little light that penetrates the depths.

Why not add some flair to the costume? Add some glitter to the belly, or even better some glow in the dark stickers/paint or some fairy lights.

N.B. Cookie cutters do not have a classic shark’s dorsal fin, only a small one towards the tail. The recommendation is for costume purposes only. Also, don’t take any flesh out of your partner for this costume.

For the flamboyant and fiery: the Pompeii worm

Pompei worms live around hydrothermal vents in the Ocean. Posted by Ocean Generation. — *Photo by National Science Foundation (University of Delaware College of Marine Studies)*

In the depths of the Ocean, there are huge chimneys belching out black and white smoke. Hydrothermal vents are where the Ocean meets the hot inside of our planet. Think of thermal spas with the heat turned way up. Combine the extreme heat with the crushing pressures and cold of the deep sea, it doesn’t sound like an appealing neighbourhood.

But they host rich ecosystems, full of incredible creatures adapted to these extremes. Hydrothermal vents may have been the origin of life on our planet.

The Pompeii worm shows a flamboyant distain for the usual limitations for life. Bright red, building a tube for itself to live in, it dances in water that would kill most. It can take the heat up to 55 degrees Celsius (131 Fahrenheit). But a woolly jumper of bacteria helps it stay cool, despite living in waters that can be over 100 degrees C (212 F). This is no normal jacket, as the worm has to keep it well fed with mucus in a symbiotic relationship*.

Four long, red-orange tentacles crown its head, used for breathing. Pompeii worms have the highest specific gill surface area of any marine worm and have acidic blood to encourage the oxygen to dissociate from their blood cells in their extreme environment. What other animal can work a feather boa with acid blood?

What you need for the costume

Pompeii worm Halloween costume, inspired by deep sea animals. Posted by Ocean Generation.

Grey/white/black trousers or skirt
Red/white long sleeve top – preferably fuzzy
Red/pink/orange pipe cleaners/paper/feather boa

Be bold. Channel your inner Pompeii worm and dance in and out of your sulfur-and-protein based tube. A fluffy or fuzzy top will show off your bacterial biofilm and use some pipe cleaners or paper to make some tentacles around your head. Smaller feeding tentacles to add a bit extra.

For the dancers: Hoff or yeti crab Halloween costume

Hoff and yeti crabs grow their own food in the deep sea. Posted by Ocean Generation, leaders in Ocean education. — *Hoff crab: University of Portsmouth / Yeti crab: A. Fifis, Ifremer/ChEss, Census of Marine Life*

Another resident of the hydrothermal vents are crabs. There are two we want to spotlight. The Hoff and Yeti crabs.

Both are named after their appearance. One has a hairy chest and so bears the name of Baywatch legend David Hasslehoff. The yeti crab is the more general term for the Kiwa genus, of which the Hoff crab is a member.

These downy decapods are covered hairs. What is the other key to their success in the deep? Dancing.

The crabs wiggle and wave, which moves water over the hairs, feeding the colonies of bacteria that live there. These crabs grow their own food in their fur, so the fuzzier the better.

What you need for the crab costume

Fuzz – for the Hoff, a hairy chest, and for a Yeti crab, get your arms fuzzy
Creative claws
Snacks in a pocket

The key for the crabs is owning your hair and rewarding your dancing. Every wiggle is a snack earner. Get fuzzy, and for added authenticity get some snacks in the fuzz for easy snacking.

For the dramatic introvert: the vampire squid

Vampire squids thrive in oxygen minimum zones in the deep Ocean. Posted by Ocean Generation. — *Photo by Monterey Bay Aquarium*

As another unfairly named creature, the Latin name of the vampire squid, Vampyroteuthis infernalis, literally means vampire squid from hell.

Red eyes, black or red colouration, and spikes lining their arms (incorrectly known as tentacles), living in the abyssal depths of the Ocean. You can see what they were going for.

Truly a survivor, these cephalopods live between 600m and 900m and can thrive where others can’t – oxygen minimum zones. These parts of the Ocean don’t have enough oxygen for most organisms to breathe. The vampire squid can survive where oxygen saturation is as low as 3% (the usual oxygen saturation in air is 21%).

If something does dare to get in their personal space, the vampire squid has a lesson for all of us: when stressed, be a pineapple.

The vampire squid will ‘invert’ itself, pulling its arms over its head, covering its photophores and revealing the spiny projections (known as cirri) underneath.

The glowing tips of its arms are held far above the head to draw attacks away from where they could do serious damage. The arm tips can grow back, so can be a handy (if you’ll pardon the pun) distraction.

What you need for the squid costume

What you need for the vampire squid Halloween costume. Posted by Ocean Generation. — *Vampire squid photo by Monterey Bay Aquarium*

Loose black or red clothing, ideally a cape
Cardboard to make some spines
Lights/sparkles
Fins on the side of the head
Red eyes

To embody the vampire squid, you need your own space. Space to let your cloak free. Line the inside with your cirri (the spines), in case of encroachment by unwanted parties. Coloured contacts or red eye makeup to give that squid from hell look.

Have fun with your lights on this one – vampire squid can control their own light show. Lights over the cloak and in your hands can make an entrancing look, ready to be muffled and switched to a spiny dark outer should the mood change.

Optional extra: Glitter juice

If the pineapple pose doesn’t work, a vampire squid has a secret weapon. A sticky cloud of bioluminescent mucus, which they can squirt at offending parties. This glowing goo can dazzle while the vampire squid escapes or stick to the transgressor and light them up for up to 10 minutes. Ten minutes is a long time to wait to see what else can see you in the dark Ocean.

A spray bottle, with some (eco-friendly) glitter mixed with water will give you your last line of defence.

*Grime, J. P., & Pierce, S. (2012). The evolutionary strategies that shape ecosystems. Wiley-Blackwell.

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Will Steen

From classroom to COP30: Questions from children to climate leaders about Ocean protection

Monthly: Impact in your inbox.

10. 10. 2025 Will Steen

How do international treaties get created?

How international treaties get created? Explained by Ocean Generation, leaders in Ocean education.

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Here are international treaties: explained.

There have been a few international treaties, like the High Seas Treaty or the Global Plastic Treaty, that impact the Ocean, but in a world of complex language and changing timelines, we wanted to make the process make sense.

The start of any treaty: Agreeing there is an issue

The first thing to understand is that the process of international negotiation is rarely a quick one. One of the fastest processes was the Montreal Protocol, the treaty to protect the ozone layer, which moved from initial scientific discovery (1973) to being signed (1987) in just 14 years.

The process of an international treaty is kicked off by proposal – a member state, or more commonly a group or coalition of states, can introduce a resolution to a governing body (such as the UN General Assembly, the UN Environment Programme etc.).

This step is about agreeing there is a problem that needs solving.

How do international treaties work? Explained by Ocean Generation.

The mandate: Permission to negotiate

So, we’ve agreed – we have a problem that needs solving. The UN governing body adopts (votes on and approves) the resolution, which is a statement of intent.

The mandate will decide the scope of the agreement – is it going to make a legally binding agreement or a voluntary one, a regional or international?

This gives the mandate to begin negotiations.  This usually means creating a committee for international negotiation – an International Negotiating Committee (INC) if you will.

Then the fun begins.

The hard part: Reaching consensus with negotiations

The INC will have a series of meetings, attended by states and “observer” parties – non-governmental organisations, industry groups and scientists amongst others.

In these meetings, they will negotiate the text of the agreement. Wording is crucial, especially for a legally binding agreement, so agreeing a draft text is usually the longest stage.

This stage is ended when consensus is reached: the vast majority of parties are happy with the contents and phrasing of the text. The text would then be adopted (voted on and agreed, in treaty language) and is open for signatures and ratifications.

What signing or ratyifying a treaty means? Explained by Ocean Generation.

What does it mean to sign or ratify a treaty?

States can sign an agreement or ratify it. Signing it is an announcement of intent, it isn’t binding but it shows that a state intends to ratify. They will often sign as a placeholder while the relevant domestic processes are taken.

Ratifying is the full involvement (legal obligation) to the agreement, whatever it may say.

Most agreements will have a minimum number of ratifications before it comes into effect. Once enough states have ratified, the treaty will become reality. States can ratify after the treaty is in effect – latecomers are always welcome.

Implementation: From agreement to action

Once the treaty exists, a Conference of the Parties (COP) or Meeting of Parties (MOP) will take place to oversee progress, amendments and compliance. The regularity of meetings varies.

How collective decision-making works: A practical example

Imagine you live in a house with a number of other people and the heating breaks.

First, one (or more) of you could raise this in the house group chat. You present evidence of the issue (the heating doesn’t come on, and the house is cold). Some housemates may have a warm room, and don’t agree initially. More evidence may be required – bring in a GP to talk about increased risk of illness or put some thermometers around the house.

When the housemates agree the heating is broken, and they would be better off if it was fixed, they agree to have a house meeting (or five) to discuss how to go about fixing it.

Is it a plumbing issue or an electrical one? Who should pay for it? If one housemate uses the heating all the time while others use less, should they pay more? To avoid future heating problems, what should the temperature be set at? This happens at the pub so, it takes a while.

Then, the plan is all sorted, but to get the ball rolling everyone needs to give a go-ahead. Five out of seven thumbs up in the group chat is the green light.

It may take a couple months while people save from their pay checks, but finally there are five thumbs up and the heating can get fixed.

The last two were grumbling about the hot water use but gave the thumbs up later on so they can use the heating.

Success Story: How the Montreal Protocol was created to protect the ozone layer

The Montreal Protocol is one of the biggest wins in international cooperation. In the 1970s, scientists Frank Sherwood Rowland and Mario Molina started to hypothesise that chlorofluorocarbons (CFCs) were depleting the ozone layer.

CFCs were a replacement for toxic refrigerants used in the 1920s, developed in the lab. They were used in aerosol sprays and any units needing refrigerant – refrigerators, air conditioners, cars, water chillers, for example.

The depletion of the ozone layer was shown to result in an increase in UV-B radiation, leading to higher rates of skin cancer and damage to crops and marine phytoplankton (the little guys producing over 50% of our oxygen).

Aerosol and halocarbon industries lobbied against regulation. A board member of a company with 25% market share in CFCs, was quoted as calling the hypothesis, “a science fiction tale…a load of rubbish…utter nonsense”.

The treaty text was agreed on 16 September 1987, with the condition that it would come into force if 11 parties had ratified by 1 January 1989.

It met this condition and has since been ratified by all 198 parties in the UN, becoming the first treaty to do so.

Since the treaty, the ozone layer has been recovering and is projected to reach 1980s levels between 2040 for most of the world and 2066 for Antarctica.

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Will Steen

From classroom to COP30: Questions from children to climate leaders about Ocean protection

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8. 10. 2025 Will Steen

What is the Global Plastics Treaty?

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The Global Plastics Treaty refers to the (currently undefined) international agreement by which the countries of the world hope to reduce plastic pollution.

How far have we got? Progress in the Global Plastic Treaty talks.

In 2022, 175 countries of the world signed an agreement that declared: plastic pollution needed to be addressed. Stronger than that, plastic pollution should be ended.

To meet this goal, countries agreed on a series of meetings across the globe to discuss and negotiate how to end plastic pollution and write it into international law (a treaty).

Five meetings were planned, with the treaty aimed to be finalised by the end of 2024.

This agreement created the International Negotiating Committee (INC) which first met in Punta del Este in Uruguay. Subsequent meetings happened in Paris, France; Nairobi, Kenya; Ottawa, Canada; and Busan, Korea.

By the end of the fifth meeting, no agreement had been reached for the Global Plastics Treaty, so another (INC5.2) was scheduled for August 2025 in Geneva. However, this meeting also ended with no treaty.

Timeline of the Global Plastics Treaty. Posted by Ocean Generation. — *Timeline by Will Steen*

What is stopping a treaty being agreed?

For the treaty to come to life, all countries must agree on the terms, so while some disagree there will be no treaty.

The main point of disagreement is whether making new plastic (plastic production) should be limited within the treaty. Countries are split largely into two groups, the High Ambition Coalition and the Global Coalition for Plastics Sustainability.

What is the High Ambition Coalition?

There is a large group of countries (around 100) in a group, called the High Ambition Coalition (HAC).

The HAC has been pushing for the plastics treaty to include plastic production limits – reducing the amount of new plastic made. Before INC5.2 the HAC published a “wake-up call” at the United Nations Ocean Conference at Nice in June 2025, outlining a ‘wishlist’ of five points:

Limits on plastic production (to be regularly adjusted), and reporting on production, import and export of primary plastic polymers
Phase out most harmful plastic products and chemicals of concern
Improve the design of plastic products to minimise environmental and human impacts
Financial support to support less developed countries in the transition
A treaty responsive to changes in evidence and knowledge

What is the Global Coalition for Plastics Sustainability?

Another group of countries formed the Global Coalition for Plastics Sustainability (also known as the Like-Minded Group of Countries).

A statement from a member country outlined the focus:

“The [Global Plastics Treaty] should pave the way for improving the waste management systems in general, and to promote environmentally safe and sound management of hazardous plastic wastes, and to reduce uncontrolled hazardous plastic pollution.”

They want a bottom-up approach, prioritising dealing with plastic waste.

What's next for the Global Plastics Treaty? Explained by Ocean Generation.

What do major businesses think of the plastics treaty?

Businesses that produce and use plastic are key to tackling the plastic pollution problem.

The UK hosted a roundtable with major business in June 2025 and produced a statement. It called for the plastics treaty to address the whole lifecycle of plastics, amongst other things.

“As businesses and financial institutions, we stand ready to mobilise significant investments, and engage with the companies we invest in, towards achieving the objectives of the legally binding instrument, including towards innovation and infrastructure.”

Other businesses, such as fossil fuel companies (99% plastics are made from fossil fuels) take a different view:

“While there have been calls for production caps or bans, it’s been reassuring to hear leaders share their belief that such measures could deprive the world – particularly the developing world – of the untold benefits plastics deliver in terms of health, food safety, the environment, the energy transition and more.” – Exxon Mobil President

What’s next for the Global Plastics Treaty?

The division has been entrenched from early in the process, with little movement on either side. It has led to questions about the process, and where to go next. Here are some options:

The process is changed to being decided by vote rather than by consensus, to make progress despite the disagreement of a small minority
The process continues via other means. For the Ottawa convention on landmines, a number of countries compiled texts outside of the process, that were then agreed upon. We could see this happening, for example, with the High Ambition Coalition.
Another round: INC5.3 to try again! A (currently unnamed) country has offered to host, but has said they will not fund it.

While the gears of global negotiation can feel like they turn slowly, they are turning. Read more about how international treaties work here.

These countries have agreed that ending plastic pollution is an important issue. We want a world without the damage of plastic pollution.

The Global Plastics Treaty is the representation of international intent. If it does produce legal guides to end plastic pollution, it will speed up progress. That it hasn’t yet is not going to stall momentum.

Plastic pollution is an international target.

The Global Plastics Treaty aims to end plastic pollution. Posted by Ocean Generation, leaders in Ocean education.

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Will Steen

From classroom to COP30: Questions from children to climate leaders about Ocean protection

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23. 09. 2025 Will Steen

What is the High Seas Treaty?

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Everything you need to know about the High Seas Treaty

Officially, it is the Agreement on the Conservation and Sustainable Use of Marine Biological Diversity of Areas beyond National Jurisdiction. It is known colloquially as the High Seas Treaty. Or, BBNJ (biodiversity beyond national jurisdiction) Agreement.

It entered force on 17 January 2026, 120 days after receiving the necessary 60 ratifications on the 19 September 2025.

What are the high seas?

The high seas refer to around 64% of our Ocean’s surface.

In 1958, 63 countries signed the Convention on the High Seas, defining the “high seas” as the Ocean not within territorial waters.

In 1982, the United Nations Convention on the Law of the Sea (UNCLOS) was signed, establishing exclusive economic zones (EEZs) reaching 200 miles out to sea– each country has sovereign rights (‘ownership’) to the Ocean and seabed within 200 miles of its coast.

The rest of the Ocean, including the water column and “the Area” (the seabed outside these EEZs), are the high seas.

What are the high seas? Explained by Ocean Generation, leaders in Ocean education. — *Map by Dr. Jean-Paul Rodrigue*

What does the treaty do?

Enables the creation of Marine Protected Areas (MPAs) on the high seas – outside of national waters.
Requires nations to conduct environmental impact assessments before marine activity.
Mandates the sharing of marine genetic resources and digital sequence information sourced from areas beyond national jurisdiction (ABNJ) between Parties (countries included). This includes monetary and non-monetary benefits.
Share marine technologies between Parties, including funding mechanisms. This is aimed to enable developing nations to contribute to and benefit from Ocean conservation.

What does the High Seas Treaty do? Posted by Ocean Generation.

What is the process?

The agreement can be traced back to December 2017, when the United Nations General Assembly voted to start creating the High Seas Treaty.

The agreed-upon five meetings (with a gap due to COVID-19) failed to produce an agreement.

In March 2023, at the sixth meeting, the text of the agreement was finalised. The treaty was open for signatures for two years, from 20^th September 2023, until 20^th September 2025.

68 countries immediately signed the agreement, and another 13 signed in the two days after.

Palau was the first country to ratify, in January 2024.

At the United Nations Ocean Conference in June 2025, there were 20 signatories and 19 countries ratified, bringing the total number to 51.

What’s the difference between signing and ratifying?

Signing the agreement and ratifying are not the same. Signing is announcing the attention to ratify. Ratifying the agreement means committing to the agreement officially.

There is no deadline on ratification after signing; Parties can ratify at any point. Only Parties that have ratified the treaty are legally bound by it, and able to enjoy the benefits.

The High Seas Treaty will come into force January 2026. Posted by Ocean Generation.

When did the High Seas Treaty come into force?

On 19 September 2025, Morocco became the 60^th country to ratify. This initiated a 120 day countdown, which ended on January 17^th 2026. From then, it is legally binding (for those who have ratified).

A year on, the first Conference of the Parties (COP) will meet to discuss high seas conservation, such as identifying the areas to protect. Belgium and Chile have submitted bids to host the Secretariat, and Chile has included a suggestion for the first high seas MPA.

Why protecting the high seas is so important

The high seas used to be out of our reach. Untouchable and unaffected by human activities. But in just the last sixty years or so, our technology has improved, this vast wilderness has become far less wild.

This has enabled us to benefit from the Ocean beyond our national borders. Fishing flotillas can travel the world and cargo ships cris-cross the Ocean. This global reach – impossible to our grandparents – has changed our relationship with the Ocean.

Without responsibility or ownership over the high seas, everyone has an incentive to extract as much as they can before anyone else. In just six decades, this free-for-all has led fishing stocks being depleted, marine animals being exposed to large amounts of noise from marine traffic and pollution accumulating out at sea.

The High Seas Treaty aims to solve this and enables the protection of important marine areas that don’t belong to any single nation. It enables the world to take responsibility for the wild Ocean.

A common misconception is that the end goal of conservationists and the marine industry (such as fishing and tourism) are incompatible. But healthy fish stocks are all a fisherman asks for, flourishing ecosystems pull in tourists and rich biodiversity offers untold discoveries and advances in pharmaceuticals and engineering to name but two.

Protecting the Ocean means letting it thrive, and we all enjoy the boon of a thriving Ocean.

The High Seas Treaty creates an opportunity. An opportunity to nurture our Ocean and share the benefits from it.

Ocean Generation’s Statement on the High Seas Treaty:

“We are delighted to hear that the UN High Seas Treaty has finally become a reality.

A healthy Ocean is vital for the survival of all living things, and this is the message we continue to deliver through our work at Ocean Generation. Protecting 30% by 2030 must, however, be seen as a minimum requirement.

We view this agreement as a starting point. The Ocean is our ally in the fight against climate change and we must stop underestimating its role in our survival.”

Jo Ruxton MBE
Founder of Ocean Generation

Protecting the Ocean means letting it thrive. Posted by Ocean Generation.

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Will Steen

From classroom to COP30: Questions from children to climate leaders about Ocean protection

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11. 09. 2025 Elliot Yu

How do the Sounds of Kelp Forests Change?

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The age-old question goes “If kelp falls in a kelp forest and no one is around to hear it, does it make a sound?” … or something like that.

The study of kelp forest soundscapes is new, but it is essential to understanding the ecosystem.

What are kelp forests?

Kelp forests are incredibly diverse and important ecosystems of organisms living within dense areas of (surprise) kelp in coastal regions.

Kelp forests, and more generally seaweed forests, act as major carbon storage for the planet and are, when compared to the woods, incredibly diverse, containing mammals, arthropods (shrimps), echinoids (sea urchins), brachiopods (a shelled animal that feeds via filter feeding) and much more.

What does the Ocean sound like?

The Ocean is surprisingly noisy. Sound is used to convey information over long distances, and to neighbours on the reef or in the grass. In water, sound travels farther than either light or chemical cues and moves almost five times as fast as it does in air.

Marine mammals like whales and dolphins are famously loud and use sound to communicate. Sperm whales can reach volumes louder than jet engines. But a shocking truth is that other marine animals contribute to the Ocean soundscape too! For example, did you know that some fish make hums and purrs?

Beyond marine animals, there are other sound sources in the Ocean. Geological sounds (earthquakes and landslides) and our own human activity (engines and drilling) have their own effects on the Ocean soundscape.

What do kelp forests sound like?

Kelp forests are an unfamiliar setting to most of us, so to assist on our adventure of the soundscape, we’ll venture through the woods at the same time.

In the woods, we hear distinctive, familiar noises. The twitter of birds, the chattering of rabbits and the chirps of insects dominate the soundscape. In kelp forests, we can hear the different calls of fishes and the frequent snapping of shrimp.

The noises of kelp forest can be separated by their pitches. Generally, lower tones contain the noises of marine mammals and fish. The higher tones we’d hear contain the clicks of snapping shrimp and the sound of echolocating dolphins (although this is higher than the human ear can hear so it’s silent to us).

These soundscape features often change in both environments over time due to natural factors, like seasonal changes, or human activity.

Daily changes in the kelp forest soundscape

As the night comes, the sounds of the daytime animals switch to the noise of nocturnal animals.

In the woods, hooting owls and squeaking bats take over the soundscape along with the occasional chirp from foxes. This daily change is seen in kelp forests too, where the activity of animals and therefore the volume of their sounds shifts over the course of the day.

For some species of fish, their noise peaks at sunset and dips at sunrise. As well as this, snapping shrimp are nocturnal, which shows in their activity, as they have peaks at sunset and sunrise but a decreased activity during the day.

Seasonal changes in the kelp forest soundscape

With the arrival of autumn and winter in the woods, some animals migrate or hibernate, removing their noises from the soundscape.

A seasonal change also occurs in the kelp forest, where the time of year can affect the presence of animals.

The Plainfin Midshipman fish makes nests near the coast and uses a humming noise to attract a mate. This humming is heard in the kelp forests during late spring and summer, consistent with their mating season. Contrasting this, the presence of snapping shrimps is maintained year-round.

Plainfin Midshipman fish humm during spring and summer. Posted by Ocean Generation. — *Photo by Sara Thiebaud*

Human influence on kelp forest soundscapes

On our walk through the woods, we come across barren spots without trees, caused because of storms or fires. Similarly in the Ocean, an abundance of sea urchins and a lack of suitable food can cause them to feast on kelp clearing the area and leaving a space overrun with small, malnourished sea urchins, with the East Fish camp in California having an urchin density of 26.8 urchins per square metre.

Although urchin barrens may seem like a natural environment, they are created by human activity, just as extreme weather can become more prominent because of global warming.

Normally, sea otters and the occasional fish prey on urchins before the situation gets out of hand. But, due to hunting and overfishing, sea urchin predation is decreased, allowing their population to spike and kelp forests to be removed.

Urchin barrens influence the kelp forest soundscape. Posted by Ocean Generation. — *Photo by Ed Bierman*

Sea urchin barrens influence the kelp forest soundscape as the region becomes less suitable for some species and more suitable for others. When hundreds of sea urchins move in, they change biodiversity.

A more direct human influence on woodland soundscapes is deforestation. The direct removal of trees by humans to clear space or for resources is easily a big issue, as it decreases habitat space, reducing biodiversity and harming ecosystems.

A similar situation happens with kelp as it can be harvested, as it has uses like in food and beauty products. As a consequence, the amount of kelp is decreased, showing little to no recovery after two years, and biodiversity can change to be unlike before harvesting.

Does human noise affect kelp forests?

Listening in our woods, we don’t only hear animal noises but also human noises. Cars on roads which cut through the woods or heavy machinery operating can create loud persistent noises which can disturb the soundscape, affecting the distribution of the animals.

The same is true for animals in the Ocean. Loud noises like drilling and seismic surveys are loud and the noise can be emitted for tens of kilometres, causing confusion and hearing damage in marine mammals and fish.

Other sounds like engine noises from low flying planes and boats can act as background noises which decrease the distance that animals can hear and communicate.

Sound disturbances can normally be mitigated in kelp forests by kelp’s ability to attenuate (absorb and decrease) sound. However, because of the removal of kelp forests, this mitigation can quickly be removed.

The building of docks and other structures may seem like they could bring back attenuation, but they can also transfer noise from cars and docking boats into the Ocean, affecting microenvironments.

What can we do?

It may seem daunting that humans can cause all of this damage, but not all change is bad. Just as forests can be replanted and wildlife protected, as can kelp forests.

The growth of kelp can be stimulated, and areas can become marine protected areas, which can allow areas to be conserved. An example of this is in New Zealand, where an urchin barren has recovered back into a kelp forest within a marine protected area over the period of 20 years.

Looking at how we live our lives, like where our fish comes from or our usage of boats can make a difference in helping this delicate ecosystem.

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Elliot Yu

From classroom to COP30: Questions from children to climate leaders about Ocean protection

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5. 09. 2025 Elliot Yu

Is Seaweed the Secret to Ditching Plastic? Explained.

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Plastics play an essential role in modern human civilisation. They are incredibly versatile, providing function in almost all aspects of our lives.

Why plastic is a problem for us and the Ocean?

Fossil-based plastics are infamous for their long-lasting impact on the environment, taking up to hundreds or thousands of years to fully break up. Along the way, they harm wildlife and people both as large plastic items and microplastics.

The impact of this is demonstrated perfectly in the Ocean, where wildlife can unknowingly eat or interact with plastics. It has been observed that every species of sea turtle has been affected by entanglement in plastic.

Plastics have another big problem. They’re sourced from oil, which contributes to their damage to the environment. 3.4% of global emissions were contributed by the plastic lifecycle in 2019, with 90% of that being emissions from production and converting fossil fuels into plastic making materials.

What's wrong with plastic - for us and the Ocean? Explained by Ocean Generation.

What are microplastics?

Microplastics are plastic particles less than 5mm in size formed from the breakup of plastic. They’re found across the planet, from deep in the Ocean to the snow high in the mountains. They’ve even been found in the human body. We don’t fully know yet what that means for our health, but we do know they harm marine life and can travel up the food chain.

Single use plastics, like plastic bags and straws, are big contributors to plastic waste, making up approximately half of all plastic waste. We only use them once and then throw them out, which means more and more plastic needs to be made to maintain supply.

What is the solution to our plastic usage problem?

Recycling is one solution to this problem, but in 2019, the OECD estimated that only 9% of plastics are recycled.The rest is disposed of in landfill sites (50%), incinerated (19%), or goes unregulated into uncontrolled landfills, fires or the environment, including our Ocean (22%). On top of this, not all plastics are recyclable. Is there another solution?

What are bioplastics?

According to European Bioplastics, “bioplastics” are either bio-based, biodegradable, or both. Bio-based plastics are plastic alternatives which, rather than using fossil fuels to source the plastic, use biological feedstock (materials) like starch or cellulose.

Bio-based plastics are not necessarily biodegradable. Biodegradability has no clear definition or criteria, but in general, a product is biodegradable if a substance can be broken down into water, biomass and gasses. As a result of this definition, biodegradable fossil-based plastics can be considered as bioplastics.

What are the different types of bioplastics?

There are 3 distinct generations of bioplastics, all defined by what they’re made of:

1^st generation bioplastics use food crops like corn or soybeans.
2^nd generation bioplastics use non-food crops like grass and wood.
3^rd generation bioplastics use seaweed and algae.

What are bioplastics made of? Posted by ocean Generation.

What’s the major difference between using seaweed and crops?

The major difference between crop-based and seaweed-based bioplastics is where they are planted.

The first two generations of bioplastics use fertile land which could be used for growing other crops.

Seaweed bioplastics are bio-based plastics and derived from seaweed. Seaweed bioplastics don’t have the same problems as the other generations as seaweed grows in the Ocean (which there is much more of than fertile land on Earth), and require only sunlight, atmospheric CO₂ and the naturally nutritious waters of the Ocean.

They are a relatively new discovery; the first seaweed bioplastics company was established in 2010. Lady Gaga’s music career began before bioplastics were commercial.

How are seaweed bioplastics made?

The first step is letting the seaweed spores grow before they are put into a seaweed farm. They are then harvested a few months later.

The seaweed contains molecules that can be extracted via chemical processes. These have gelling and film-making (like plastic wrap, not movies) properties which make them useful in bioplastic production.

The extraction process leaves behind residuals. These leftovers can be turned into seaweed pellets which can feed back into the bioplastic making process, reducing waste. They can also be converted into methane which comes with the disadvantage of being a greenhouse gas. However, if captured and stored, it can be a carbon effective source of methane, which can be used in the chemical industry, or as a cleaner fuel than fossil fuels.

Our molecules can be mixed with other substances like nanoclays or silver nanoparticles to improve strength or change properties like making them antimicrobial.

Seaweed bioplastics are already used commercially in places like food packaging – that’s pretty kelp-ful!

Seaweed is a macroalgae growing in the Ocean.

What is the environmental impact of seaweed bioplastics?

The life cycle assessment of seaweed bioplastics looks at its carbon footprint from harvesting it from farms in the Ocean to its disposal in bins. Pilot scale assessments (these represent full production at a smaller scale) show that their production released more carbon than plastic, however, models show that scaling up production to full scale makes their carbon output less than plastics.

What are the downsides of seaweed bioplastics?

Making seaweed bioplastics relies heavily on farming and harvesting seaweed. This may present a problem when scaling up seaweed farms, especially to the size of being able to match plastic production, if this is even possible. Seaweed farms take up space in the Ocean, and they affect organisms that are living in areas where farms are viable, like seagrasses and corals by blocking light or choking them.

This problem can be mitigated by moving seaweed farms into the open Ocean and optimising growth by growing two different species in the same space. This can be done by growing buoyant kelp and non-buoyant seaweed next to each other to best use space.

Seaweed can also wash onto the coast from farms and decay, releasing pollutants that were absorbed over the life of the seaweed, affecting the local environment and limiting biodiversity.

There is also the problem that not all bioplastics are biodegradable. While it may be entirely possible that seaweed bioplastics specifically are biodegradable, there isn’t yet enough literature to suggest that this is the case.

On top of this, the definition of biodegradability has no specific time frame in which a material should be broken down in, meaning this vagueness could be taken advantage of.

This reintroduces a problem that we were trying to solve, simply sourcing the plastics from elsewhere.

Which plastic or alternative is the bets to choose?

Which plastic (or alternative) is the best to choose?

There are many factors that go into considering a product: the production, the functionality (how good it is at what it’s supposed to do) and the environmental cost.

However, it can be difficult to remove bias. Take single use paper bags for example. At first glance, they seem much more environmental than single use plastic bags as they’re biodegradable, but when put into practice, they have a higher carbon footprint in production than plastic bags and aren’t as strong. So, it’s difficult to tell which of these is better.

As more research goes into seaweed bioplastics, we may find solutions to the problems associated with them and have a more accurate understanding of their impact as they are produced on a larger scale. For now, it is better to avoid single use items altogether, and to use seaweed bioplastics where available.

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Elliot Yu

From classroom to COP30: Questions from children to climate leaders about Ocean protection

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3. 09. 2025 Peter Reynolds

What Happened to the Steller’s Sea Cow? Explained.

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There are two theories about what happened to Steller’s sea cow. Let’s unpack them.

Steller’s sea cow was a 7-metre-long, 5-tonne cousin of the manatee; known to graze peacefully in kelp forests. But just 30 years after the sea cow’s discovery – it vanished from the Ocean forever.

In this article we’re going to explore two theories for why this marine species disappeared. Both involve hunting, but one requires an understanding of the habitat that Steller’s sea cow called home: the kelp forest.

By looking at this complicated history, we can begin to understand the complex interactions going on under the Ocean surface, and learn lessons about how we can best preserve these incredible ecosystems in the present.

Steller's sea cow was a 7-metre-long, 5-tonne cousin of the manatee. Posted by Ocean Generation. — *Steller’s sea cow sketch by Biodiversity Heritage Library*

The story of Steller’s sea cow starts with a shipwreck.

On the 6th November 1741, the Svyatoy Petr was shipwrecked on an isolated and uninhabited island, now known as a part of the Commander Islands chain. For several months, the crew of sailors, cartographers, geographers, and natural historians had been carrying out one of the first scientific explorations of the North Pacific.

Stranded for nearly a year, the remaining crew salvaged materials from the wreckage, and built a ship that could cross the Ocean back to Russia.

One of the most consequential outcomes of this failed expedition was the presence of a curious and observant naturalist, George Wilhelm Steller. For almost a year, he made meticulous observations, sketches, and notes on the unfamiliar and captivating wildlife that surrounded him, which have been left to us as an invaluable historical and ecological artefact.

From a massive population to extinct:

One creature left a particularly strong impression on George Steller. He wrote in his journal of ‘gigantic manatees grazing all about the island’s lagoons’. These cousins of the manatee would often exceed 5,000kg in weight. He observed that they were very sociable creatures, sticking in large herds and eating kelp floating at the Ocean surface as though it were grass, ‘in the same way as horses and cattle’.

Although Steller wrote that they were so numerous that ‘that they would suffice to support all the inhabitants of Kamchatka’, a twist of fate left them extinct by the 1760s. To understand them, scientists have had to look at historical evidence and their closest living relatives, dugongs and manatees.

Sketch of a Stellers sea cow. Posted by Ocean Generation.

Story One: Hunting

Steller’s crew hunted sea cows as a source of food whilst stranded on Bering Island. Steller recalled a story in his journal about the psychological stress this placed on them. Whilst hunting a female sea cow, a male aggressively followed and tried to ram their boat, following all the way to shore long after the female had died. They also hunted other creatures including otters and seals.

This is the most common theory for the extinction of the sea cow: they were exploited for their meat, fat, and hides, the latter of which would be used in the construction of boats. This theory suggests that the hunting was so widespread and unsustainable that the population was put under great stress and collapsed within 30 years.

Story Two: Loss of Keystone Species

In the past few decades, a group of scientists have put forward an alternative theory.

This theory pays attention to the complex dynamics of kelp forests, and the role that sea otters play as ‘keystone species’: species that play a disproportionate role in managing the ecosystems they call home. As we explained in a recent article, sea otters’ appetite for sea urchins prevents overgrazed ‘urchin barrens’ emerging – desolate stretches of rock with little to no vegetation – in the place of lush and biodiverse kelp forest. Do read this article if you want to learn more!

Difference between an urchin barren and healthy seafloor. Posted by Ocean Generation. — *Urchin barren photo by Ed Bierman, healthy seafloor photo by Zachary Randell*

Whilst Steller’s sea cows were hunted on these expeditions, sea otters were the main pursuit. When the first groups returned with the fur pelts of sea otters, traders were so astonished at their thickness and quality that they sold for nearly 100 rubles a pelt – 25 times more than the equivalent pelt from land animals. It’s been said that they were, at some points, worth more than gold! In the wake of the euphoria that ensued, the sea otter population collapsed so quickly and dramatically that they were observed to be at the brink of extinction around the Commander Islands by 1753.

Kelp forests create a complex habitat for a diversity of species, with one study in Norway suggesting that the average piece of kelp in their study site supported 8,000 individual organisms. If sea otters are lost to hunting, the kelp forests can be transformed into urchin barrens, as there are no otters to control sea urchin populations. As kelp is lost, the Steller’s sea cow loses their source of food, a change to their environment that might have ultimately resigned them to extinction.

Sketch of a sea otter by Steller. — *Sketch of a sea otter by Steller*

Which theory about the extinction of Steller’s sea cow is it?

Both theories are reasonable. Ecosystems are complex and difficult to understand completely, and it is probably a bit of both. As I have been reminded by one of the scientists who proposed the second theory, ‘the lack of good data from the extinction of sea cows means that we are unlikely to ever really know.’

Sea cows may be extinct, but this story is not irrelevant, and shouldn’t be the cause of doom and gloom or eco-anxiety.

As scientists have better understood the role of sea otters as a ‘keystone species’ that maintain kelp forests, we have become more capable of putting conservation programmes in place that work. The recovery of sea otter populations in the Pacific is arguably one of the greatest success stories of conservation, bringing back both populations of sea otters and the coastal ecosystems they engineer such as kelp forests. At the moment, we can look to innovative projects such as the Monterey Bay Aquarium’s surrogacy programme for hope, which raises orphaned pups so that they can be reintroduced back to the wild. (You can see them on the aquarium’s live stream here!)

We may have lost Steller’s sea cow, but we can still restore kelp forests for the countless other species that call it home.

Steller had a sense for the value of sea otters, though he may have primarily seen them as creatures to hunt. He even wanted to bring some home as pets. ‘The sea otter,’ he wrote, ‘deserves the greatest respect from us all’. Although he couldn’t have understood the complex work that they do as a ‘keystone species’ as we do today, we can all wholeheartedly agree with him.

Sea otters are guardians of kelp forests. Posted by Ocean Generation.

Cover image via Biodiversity Heritage Library

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Peter Reynolds

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29. 08. 2025 Peter Reynolds

How Do Sea Otters Make Themselves at Home in the Kelp Forest?

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What comes to mind when you think of sea otters?

The internet is filled with videos of pups snuggled against their mother’s chest, ‘rafts’ of sea otters holding hands or wrapping themselves in kelp so they don’t drift apart as they nap, and cracking open shells or showing off the pouches in their armpits where they stash their favourite rocks and snacks. They are undoubtedly one of the Ocean’s most adorable and loved creatures.

But more complicated things are going on below the surface.

As well as capturing our hearts, they are ‘keystone species’: species whose everyday eating, resting, and playing has a disproportionately large role in maintaining the entire ecosystem around them. This article will explore how otters make themselves a home in the kelp forest, and how they’re otterly (sorry!) essential to maintaining one of our Ocean’s most vibrant ecosystems.

A group of resting sea otters is called a raft. Posted by Ocean Generation.

Where do sea otters live?

Sea otters (Enhydra lutris) have a range that covers the North Pacific, stretching around a coastline that extends between Japan, Russia, Alaska, and California.

Current and historic sea otter range, posted by Ocean Generation. — *Map: Future Directions in Sea Otter Research and Management*

What connects all these places? Offshore – out of sight and below the surface – this whole stretch of coastline is a chain of ‘kelp forests’: magical ecosystems that are teeming with life. Whilst sea otters don’t only live in kelp forests, they are most at home in them as it provides them with food and shelter.

Kelps are a range of brown macroalgae (seaweed, to you and me) that grow up to 50m in length. The brown colour comes from a particular pigment that allows them to capture light below the Ocean’s surface. Like plants on land, they photosynthesise sunlight into organic material, which produces the energy for an entire complex food web around it.

This is the base for an incredibly rich and diverse habitat, and one study in Norway found that the average piece of kelp provides habitat for 8,000 individual organisms, with some even providing habitat for over 80,000!

Kelp forests are home to a range of Ocean species. Posted by Ocean Generation, leaders in Ocean education.

What do sea otters eat?

If there’s one thing sea otters can do, it’s eat. Studies have estimated that they need to eat between 19% and 39% of their body weight in food to meet their basic needs. To put this in perspective, this would be the equivalent of a person needing to eat about 20 pizzas every day!

As well as sea otters, kelp forests are home to a wide range of other species including fish, seals, and seabirds, and invertebrates such as molluscs, lobsters, and sea urchins. Many of these invertebrate species are found in sea otter diets, but at the top of the menu are sea urchins.

In fact, some sea otters crack open and eat so many purple sea urchins that their bones are dyed a pink to purple colour from the compounds they contain.

Sea otters love eating sea urchins. Posted by Ocean Generation. — *Sea otter skull image by Peter Monteforte*

How are sea otters ‘keystone species’?

A ‘keystone species’ is a species ‘whose impact on its community or ecosystem is large, and disproportionately large relative to its abundance’. This means that if they are lost from an ecosystem, it can disrupt everything else within it. In the case of the sea otter, losing them can even indirectly lead to the loss of kelp. We have explored a historical case where this happened in an explainer article here.

But how does this happen?

The greatest threat to many kelp forests – especially, but not only, in temperate parts of the Ocean – is overgrazing from sea urchins. When their numbers are left unchecked, sea urchins sweep their way across the seabed, devour all the kelp they come across, and leave nothing but a desolate rocky seafloor known as an ‘urchin barren’.

The varied heights of kelp creates a habitat with different levels that can be compared to the differences between the canopy and floor of forests on land, meaning a diversity of species can call it home. Once an urchin barren forms and kelp is taken out of the ecosystem, the many other species that rely on it for food and shelter can also be lost.

Kelp is a complex habitat that supports a range of small species, which makes it a healthy breeding ground and nursery for fish. This attracts larger species such as seals and seabirds, who suffer knock on effects along with fish when kelp forest is lost.

This is where our sea otter’s taste for urchins can come in handy. Sea otters can break through sea urchins’ tough, prickly exterior for food, and do so in such large numbers that they play a crucial role in managing populations. They’re accidental conservationists!

How are sea otters part of conservation efforts?

Sea otter populations had declined very significantly by the 20^th century. At the time when much of the initial research was being done on the relationships between sea otters, sea urchins, and kelp, one marine scientist publicly shared his worries that the kelp forests of the Pacific had gone through ‘irreversible degradation’.

However, we now know that just as marine ecosystems can be lost much faster than those on land, some can also be restored much faster. The abundance of sea urchins in overgrazed urchin barrens means that sea otters can quickly recolonise their former range.

Sea otters have a long history of being at the heart of conservation efforts. Hunting them in parts of Alaska and Russia was banned in 1911 in the first ever piece of wildlife conservation policy, and banned throughout the United States in the 1970s.

More recently, sea otter ‘translocations’ – where populations are moved to parts of their former range so they can recolonise it – have reintroduced sea otters to parts of the North Pacific such as Southeast Alaska, British Columbia, Washington, and San Nicolas Island in California. As the relationships between them and the kelp forests they live in has become better understood, reintroducing otters has become more than just about them, but the whole kelp forest ecosystem they can create too.

An exciting project has been taking place over the past few decades at the Monterey Bay Aquarium in California, where orphaned sea otter pups are rescued, rehabilitated, and released back into the wild. Between 2002 and 2016, they reared and reintroduced 37 individuals, with benefits not only for sea otter populations but the integrity of the ecosystem as a whole.

The North Pacific kelp forest: A place to call home

Marine scientists have carried out experiments where they observed the differences between how sea otters behave in parts of the Ocean which have kelp forest in comparison to those places without. As a result, it’s possible to see that the otters themselves benefit from their unwitting conservation work.

Firstly, sea otters love to be around kelp as it is a safe habitat for them. At low tide, kelp sits on the surface of the Ocean, and sea otters wrap up their pups in the strings of kelp so they don’t drift away while they nap or hunt. Their role in clearing the urchin barrens can be really kelpful – restoring the very kelp in which they live!

Secondly, the sea urchins that sea otters catch from urchin barrens are not as nice as the ones in kelp forests. They are small, bad quality, and have poor nutrition. Scientists have estimated that due to the difference in quality, sea otters living outside of kelp forests in the Aleutian Islands in Alaska would need to eat about 1,085 urchins every day to meet their basic needs, compared to just 484 in areas with healthy kelp forests. This means that by restoring kelp ecosystems, sea otters save time and get an extra hour and a half every day to nap or frolic around on the Ocean surface.

Kelp forests can also sustain a more biodiverse and complex food web than urchin barrens. Those otters with a taste for fine foods aren’t stuck with urchins for dinner every day. If you had to eat sea urchins every day, you’d probably be bored and want a change too, right? Kelp forests offer sea otters a more varied diet, from a much larger range of sea creatures including crabs, clams, sea snails, scallops, and mussels.

Why sea otters love kelp forests: Explained by Ocean Generation.

Just an-otter brick in the wall?

So, how do otters make themselves at home in the kelp forest? The answer is simple: just by being their adorable and authentic selves. If there is one take away from this article, it’s that the health of sea otters are entangled in that of the kelp forest ecosystem they call home.

If you ever find yourself scrolling through cute videos of otters on the internet, just remember, they are not just cute and furry, but truly precious and wonderful engineers of the Ocean’s ecosystems.

Post by

Peter Reynolds

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