{"id":36321,"date":"2026-09-04T18:30:00","date_gmt":"2026-09-04T22:30:00","guid":{"rendered":"https:\/\/www.ecoticias.com\/en\/?p=36321"},"modified":"2026-09-04T13:02:05","modified_gmt":"2026-09-04T17:02:05","slug":"a-tiny-european-native-oyster-can-filter-about-200-liters-of-seawater-a-day-and-release-up-to-2-million-larvae-at-once-yet-its-reefs-have-collapsed-across-much-of-europe-and-uk-populations-have-falle","status":"publish","type":"post","link":"https:\/\/www.ecoticias.com\/en\/a-tiny-european-native-oyster-can-filter-about-200-liters-of-seawater-a-day-and-release-up-to-2-million-larvae-at-once-yet-its-reefs-have-collapsed-across-much-of-europe-and-uk-populations-have-falle\/36321\/","title":{"rendered":"A tiny European native oyster can filter about 200 liters of seawater a day and release up to 2 million larvae at once, yet its reefs have collapsed across much of Europe and UK populations have fallen by around 95%"},"content":{"rendered":"\n

Imagine an animal of the size of a teacup being able to filter 200 liters of seawatera day<\/a>. Or one single female, of only 8 centimeters, releasing millions of larvae.<\/p>\n\n\n\n

Still, European native oyster populations are not doing so well. In the UK, their populations have fallen by about 95 percent since the mid-19th century, leaving the reef ecosystems completely collapsed<\/a>. It is quite a paradox: how is it possible that an animal that is so fertile is disappearing?<\/p>\n\n\n\n

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Read More: A tiny European native oyster can filter about 200 liters of seawater a day and release up to 2 million larvae at once, yet its reefs have collapsed across much of Europe and UK populations have fallen by around 95%<\/a><\/h4>\n<\/div>\n<\/div><\/div>\n<\/div>\n\n\n\n

It is important to say that the European native oyster (Ostrea edulis) is the only true oyster native to UK seas. Their biology is surprisingly flexible, because they tend to start their lives as males until they turn into females (this is around 2 or 3 years old, which is when they reach their sexual maturity). What also is really impressive is that they can change their sex many times during their lives, something known as \u201cprotandrous alternating hermaphroditism.\u201d<\/p>\n\n\n\n

When a female matures, she can release between 1 and 2 million larvae in a single reproductive event. But remember that these numbers refer to larvae and not of adult oysters!<\/p>\n\n\n\n

Why two million larvae can still fail<\/h2>\n\n\n\n

The problem here is that oysters really need to settle on top of living or old shells from past generations, and having the reefs destroyed by fishing makes it very difficult for them to survive.<\/p>\n\n\n\n

A remarkable life cycle built around change<\/h2>\n\n\n\n

That is why reproduction alone will not solve the oyster population problem. Nowadays, researchers compared records of densities from the past and the results are quite alarming, since the historical reefs used to cover more than 1.7 million hectares<\/a> and now those numbers are drastically reduced.<\/p>\n\n\n\n

A water filter beneath the waves<\/h2>\n\n\n\n

Oysters in order to eat, they pump water through their microscopic hairs on their gills and capture for example phytoplankton.<\/p>\n\n\n\n

They also have a big responsibility because they are constantly removing excess nitrogen in the water around them, because having too much of it can cause harmful algal blooms<\/a>. This definitely is a big danger to fish and marine species, since this causes toxic algae that strip oxygen from the water.<\/p>\n\n\n\n

Oyster reefs work like coastal neighborhoods<\/h2>\n\n\n\n

With time, millions of living and dead shells tend to pile up to create three-dimensional structures. These rocky reefs work as shelter<\/a> for sponges, spiny seahorses or European eels.These are not the only \u201cproperties\u201d that reefs have. If they are healthy, they are able to stabilize sediment, reduce coastal erosion and protect salt marshes and seagrass<\/a>. Also, in some more specific situations, they can even play a big role in carbon storage.<\/p>\n\n\n\n

London once consumed them by the hundreds of millions<\/p>\n\n\n\n

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Read More: Engineers lowered a giant steel structure into the water off the Florida Keys where it will deliberately remain on the seabed, but what looks like abandoned industrial hardware is designed to become something alive<\/a><\/h4>\n<\/div>\n<\/div><\/div>\n<\/div>\n\n\n\n

As you might know, humans have harvested oysters for many and many years. It is even said that this has happened since 8700 BC. In the Roman Empire they ate European native oysters, and for example, in the 19th century more than 200 million<\/a> was the estimated number sold each year in London when the city\u2019s population did not reach two million.<\/p>\n\n\n\n

That level of consumption ended up destroying the ecosystem. Fisherman not only took the adult oysters, but they also destroyed the shell beds that the larvae needed to live on. And if you add pollution,habitat loss and the invasion of exotic species<\/a>, what seemed to be an endless source of food, ended up collapsing Restoration is moving from cages to seabed reefs<\/p>\n\n\n\n

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Read More: Britain is dropping 20 concrete reef cubes and 44 tons of scallop shells into the sea, and the goal is to bring back oysters down more than 95% since the 1800s<\/a><\/h4>\n<\/div>\n<\/div><\/div>\n<\/div>\n\n\n\n

Luckily things are starting to change and there is a real seabed restoration taking place. In May 2026, the Solent Seascape Project<\/a> placed 20,000 native oysters on a new reef built in Chichester Harbour. It is one of the largest subtidal oyster reef restorations in the UK, something that was possible thanks to 260 volunteers who cleaned the shells one by one.<\/p>\n\n\n\n

\"Diver
A diver inspects native oysters placed on the seabed as part of efforts to rebuild the shell-rich reef habitat the species needs to reproduce and recover.<\/figcaption><\/figure>\n\n\n\n

As Alison Debney, conservation lead of ZSL said \u201cGiven time and space, nature can recover,\u201d<\/a> But to have them all again, it is compulsory to have clean water, disease control and years of strict protection.<\/p>\n\n\n\n

The official information was published by the Zoological Society of London.<\/p>\n","protected":false},"excerpt":{"rendered":"

Europe’s native oyster filters 200 liters of seawater daily, but populations fell 95% since the 1800s; reefs are now regrowing.<\/p>\n","protected":false},"author":19,"featured_media":36362,"comment_status":"open","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"class_list":["post-36321","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-environment","resize-featured-image"],"_links":{"self":[{"href":"https:\/\/www.ecoticias.com\/en\/wp-json\/wp\/v2\/posts\/36321","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.ecoticias.com\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.ecoticias.com\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.ecoticias.com\/en\/wp-json\/wp\/v2\/users\/19"}],"replies":[{"embeddable":true,"href":"https:\/\/www.ecoticias.com\/en\/wp-json\/wp\/v2\/comments?post=36321"}],"version-history":[{"count":2,"href":"https:\/\/www.ecoticias.com\/en\/wp-json\/wp\/v2\/posts\/36321\/revisions"}],"predecessor-version":[{"id":36363,"href":"https:\/\/www.ecoticias.com\/en\/wp-json\/wp\/v2\/posts\/36321\/revisions\/36363"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.ecoticias.com\/en\/wp-json\/wp\/v2\/media\/36362"}],"wp:attachment":[{"href":"https:\/\/www.ecoticias.com\/en\/wp-json\/wp\/v2\/media?parent=36321"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.ecoticias.com\/en\/wp-json\/wp\/v2\/categories?post=36321"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.ecoticias.com\/en\/wp-json\/wp\/v2\/tags?post=36321"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}