Outreach
Bringing the Ocean to Society
3 May 2021
Researchers of Institute of Marine Research contibute for the World Ocean Assessment
Ocean health update: Species go extinct before they are discovered

“95 percent of the deep ocean is still not described by science. That means we don’t know about all of the species that live there. Meanwhile, human impacts on the sea floor are increasing. We therefore expect various unknown species to become extinct before we discover them.”


That is the view of Lis Lindal Jørgensen, a researcher at the Institute of Marine Research (IMR) and one of the co-authors of the report, which was launched in April.


The Second World Ocean Assessment, which builds on the first assessment from 2015, provides an updated picture of ocean health.

Knowledge gaps
The report states that we currently know about more than 150,000 species of benthic fauna. Over 10,000 new species have been described since 2012. But there are still gaps in our knowledge, which moreover is unevenly distributed.

“We know most about shallow waters managed by rich countries, and least about deep waters and marine areas managed by developing countries”, says Lis Lindal Jørgensen, who had overall responsibility for the report’s chapter on benthic fauna.

Impacts of the ocean on humans
Our lack of knowledge makes it difficult to protect life in the deep ocean effectively. When species disappear, it can affect other species as well.


“The benthic fauna is important to the ocean, and to us as humans. We eat shrimps, crabs and bivalves, and in places like China they also eat sea cucumbers and many other species. In addition, bioprospecting, in other words looking for natural substances than can be used in medicines or industrial products, has had great success with marine species”, says Jørgensen.

Whale populations are increasing
Another scientist at the IMR, Mette Skern-Mauritzen, has contributed to the new report’s chapter on sea mammals.

“We have documented that several species of sea mammal remain critically endangered. However, many other species are doing well – for example the baleen whales, which were heavily hunted in the past. Their populations are now recovering”, says Mauritzen.

“The species that are critically endangered now are generally not the ones that are hunted, but rather species with limited habitats that are heavily impacted by human activities. These include the vaquita porpoise in Baja California, which often becomes entangled in fishing nets”, says Mauritzen.

There may be fewer than 20 individuals left of this species, putting it at extremely high risk of extinction.

Emissions are a health and environmental hazard
One important topic covered by the report is the link between ocean health and human health.
Bjørn Einar Grøsvik was responsible for part of the chapter on toxins and discharge from oil and gas installations. He points out that metals and persistent organic pollutants can accumulate in the food chain, creating a health risk to both animals and humans.

“In the Barents Sea, we have observed that toxin levels have fallen and then levelled off. Now we are wondering whether that is ‘good enough’”, says Grøsvik.

“In the Mediterranean and many other seas further south, toxin levels are so high that some of the top predators – like dolphins and orcas – are struggling to reproduce”, he adds.


ORIGINAL ARTICLE & picture from EurOcean's Member, the Institute of Marine Research

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