endangered marine animals


Unfortunately, the sea otter’s remarkable fur has also been the main source of its troubles.  Once known as the “sea beaver” because of the value and economic importance of its pelt, sea otters were hunted throughout their range by multiple nations beginning in the 18th century when a crew of Russian sailors discovered sea otters while shipwrecked in the Commander Islands.   By the beginning of the 20th century, a single sea otter pelt was worth over a thousand dollars.  By that same time, perhaps only 1000 to 2000 otters remained in the wild, and fear of their extinction led Russian, Canada, the US, and Japan, to sign a treaty outlawing the trade in otter fur.  Now, only indigenous peoples of the United States are allowed to hunt sea otters, and the resulting rebound of the population has been considered one of the greatest successes in the history of marine conservation.

Here’s a seriously cute photo for your Wednesday: A monk seal watches a baby turtle crawl on the beach at Papahānaumokuākea Marine National Monument. A UNESCO World Heritage Site, Papahānaumokuākea encompasses 139,797 square miles of the Pacific Ocean – including the Hawaiian Islands National Wildlife Refuge and Midway Atoll National Wildlife Refuge (usfwspacific). Many of the islands and shallow water environments are important habitats for rare species such as the threatened green sea turtle and the endangered Hawaiian monk seal.

Photo by Mark Sully.


In March 2015, by far the largest reported mass mortality of baleen whales took place in a gulf in Southern Chile. At that moment, researchers discovered 367 dead whales, from the sector of Gulf of Penas and Puerto Natales, in Magallanes region.  

In May the scientific journal PeerJ published the final study on the mass stranding event, most of them sei whale (Balaenoptera boreal), whale species which is endangered. According to the research, led by Vreni Häussermann, the event was related to the proliferation of toxic algae during the El Niño phenomenon.

While large mass mortality events are well known for toothed whales, they have been rare in baleen whales due to their less gregarious behavior. Although in most cases the cause of mortality has not been conclusively identified, some baleen whale mortality events have been linked to bio-oceanographic conditions 

According to the study if the frequency and magnitude of mass mortality events increase due to climate change this would have a significant impact on the local population and threaten the recovery of this endangered species, which in the Southern Hemisphere was reduced by whaling from about 100,000 to 24,000 individuals by 1980.

  • Reference:  Häussermann et al. 2017. Largest baleen whale mass mortality during strong El Niño event is likely related to harmful toxic algal bloom. PeerJ

Sea otters have a hunting style unique among marine mammals.  Most marine mammals such as seals and dolphins will catch fish in their jaws; only the sea otter catches fish in its forepaws.  In addition, it is the only marine mammal able to lift and turn over rocks on the sea floor in search of crabs and shellfish.  When one is found, it will be tucked into a pouch of loose skin on the otter’s chest and carried up to the surface to be eaten.


Hi guys! My next endangered marine animal is the Hammerhead Shark. It is estimated that around 100 million sharks are killed by humans each year. 🦈


(apparently) Four North Pacific right whales (very rare and critically endangered cetaceans! ) have been sighted off Japan this month.

Alisa Schulman-Janiger reports from a colleague that “two were seen off Amami Oshima island and in the port of Ushibuka, Kumamoto; another two were seen during whale-watching tours in Bonin Islands on March 12 and March 25. Later one was very curious; it kept interacting with humpbacks and watching vessels. 


The spotted handfish (Brachionichthys hirsutus), an amazing creature that walks the ocean floor, is a rare Australian fish from the family Brachionichthyidae. It is classified as Critically Endangered on the IUCN Red List 2002. is the first Australian marine species to be threatened with extinction.

The greatest threats to the handfish appear to be siltation and invasive species. The Derwent Estuary where the fish lives is highly urbanised and industrialised, and a range of marine pests have been introduced through shipping.  One key pest is the Northern Pacific Seastar (Asterias amurensis), a particularly large and voracious predator that is now abundant in the estuary. Studies by CSIRO show that the seastars eat the stalked ascidians that the handfish use to attach their eggs.


Researcher has confirmed a nesting site of the endangered Bryan’s shearwater, once thought to have gone extinct on Ogasawara island chain. The last it was seen on Midway Atoll in 1991.  Scientists conducted DNA testing on seabirds found on the Ogasawara Islands – which have been recognized as a UNESCO world natural heritage site – between 1997 and 2011, as their features matched those of the Bryan’s Shearwater.

  • Photo: A Bryan’s shearwater found on Higashijima island on the Ogasawara island chain in February 2015 Provided by the Forestry and Forest Products Research Institute