Below, readers can explore eight marine animals that have been lost forever. From the sea mink to the great auk, these incredible animals were hunted to extinction or driven there through habitat encroachment or the destruction of food sources. 

Stellar’s Sea Cow 

Date of Extinction: 18th century

Reason for being extinct: High demands for their fat and meat

Stellar’s Sea Cow 
Stellar’s sea cow skull

The Steller’s sea cow was one of two members of the Dugongidae family. It was a large animal found around the Commander Islands in the Bering Sea. It was first described, by its namesake Georg Wilhelm Steller, in On the Beasts of the Sea. The animal was hunted to extinction only a few years later as demands for its fat and meat were incredibly high. 

The animal was large, reaching lengths of up to thirty feet or nine meters. They fed on kelp and various seagrasses and had a downward-pointed snout. Today, the dugong is the only remaining member of the Dugongidae family. It is considered threaded by the IUCN but is protected throughout its entire range. 

Sea Mink 

Date of Extinction: late 19th or early 20th century

Possible reason for being extinct: Fur trade

The American mink, a close relative of the sea mink
The American mink, a close relative of the sea mink

The sea mink was a marine mammal that lived around the coast of New England. It was first described in 1903, only after it was hunted to extinction. Less is known about the sea mink due to the fact that they were only discovered after already going extinct. It was desirable as a product of the fur trade in the region. Some suggest that the sea mink was actually a subspecies of the American mink, it’s the closest living relative. 

The Great Auk 

Date of Extinction: July 3rd, 1844 

Reason for being extinct: Demand for its meat

the great auk
The Great Auk

The Great Auk is one of the best-known cases of a marine animal going extinct. It was an ocean bird that ranged from 30 to 33 inches (75 to 85 centimeters) tall and weighed around 11 pounds or 5 kilograms. The animal was hunted to extinction for its meat and down. The auk first became semi-protected in 1553, but it was not until 1794 that Great Britain banned killing auks for their feathers.
The last great auk in Great Britain was killed on the islet of Stac, an Admin in Scotland, in 1844. It was caught, kept alive for three days, and then beaten to death with a stick by men who believed it had cursed the weather. 

The final pair of auks were killed on July 3rd, 1844, while incubating their egg. The last egg was crushed under a fisherman’s boot. 

New Zealand Grayling 

Date of Extinction: early 1900s 

Possible reasons for being extinct: Fragility of freshwater system, hunting, and deforestation

New Zealand Grayling 
The New Zealand grayling grew to be around 30-45 centimeters in length

The New Zealand grayling is an extinct fish species that was native to New Zealand. It migrated between freshwater and saltwater during different seasons and was abundant during the 19th century. It was a medium-sized fish that grew to be around 30-45 centimeters in length. The fish was hunted by New Zealand natives dozens at a time. 

In the early 1900s, the population declined significantly. The last sighting of a New Zealand grayling was in 1923. The species came under protection in 1951, far too late to help. Today, scientists do not have a single cause of extinction for the fish. The fragility of freshwater systems and deforestation have both been cited as contributing reasons. 

Eelgrass Limpet 

Date of Extinction: early 1930s
Reason for being extinct: Diminishing food source and habitat (eelgrass plant)

Eelgrass, the preferred habitat and food source of the eelgrass limpet

The eelgrass limpet or bowl limpet was a species of sea snail. It was native to the western Atlantic Ocean and easy to find, for centuries, during the low tide. Its range stretched from Labrador, Canada, to New York. The cause of extinction was not directly caused by human beings. The collapse of the eelgrass plant population due to a wasting disease depleted the snail’s habitat and food source. The eelgrass survived, but the snail did not. As with the sea mink, the eelgrass limpet’s extinction was not noticed until many years (up to sixty) later. 

Caribbean Monk Seal

Date of Extinction: mid-1900s (declared extinct in 2008)

Reason for being extinct: Overhunting

caribbean monk sea in an aquarium
A Caribbean monk sea in an aquarium

The Caribbean monk seal was a species of seal native to the Caribbean. It was driven to extinction through overhunting. Hunters sought out the seal’s valuable oil and meat. They were large animals, growing to around eight feet in length and weighing up to 600 lbs or 270 kilograms. The seals had a docile nature that made them easy to hunt and kill. The last sighting of a monk seal was in 1952 between Jamaica and Nicaragua. The species was declared extinct in 2008 after a five-year search for the animal. 

Japanese Sea Lion

Date of Extinction: 1970s

Reason for being extinct: Commercial desire for their meat and oil

Japanese sea lion
Japanese sea lion

The Japanese sea lion was a type of California sea lion that went extinct in the 1970s. Sea lions were hunted to extinction due to commercial desire for their meat and oil in the 1900s. Their organs were used to make medicine, and their skin and whiskers were pip cleansers and other goods. The sea lions were found along the Pacific coastline and were large, dark grey, and could reach weights of 1,230 pounds or 560 kilograms. 

During the early 20th century, sea lions were also captured for use in circuses.

They were virtually extinct in the 1940s. It was during this period when Japanese fishermen caught an estimated 16,500 sea lions, a number scientists believe is more than sufficient to cause their extinction. 

Labrador Duck 

Date of Extinction: after 1878

Possible reasons for being extinct: Human encroachment and the gathering of duck eggs, and the decline in food sources

Labrador duck
Labrador duck

The Labrador duck was a North American bird that was last seen in 1878 in Elmira, New York. When European settlers arrived, they helped to drive the duck from its habitat. The males of the species had black and white feathers, and the females had grey. They had small heads, eyes, and long bills. The body was short, and the tail was rounded. It migrated during the winter but preferred the coasts of Labrador, where it bred. 

Their extinction is not fully explained to this day. The ducks were not hunted, but it’s likely that human encroachment and the gathering of duck eggs were responsible. The decline in food sources has also been cited as a possible reason. 


What is the most threatened marine animal? 

The vaquita is the world’s rarest marine animal. It is a cetacean, like a whale or a dolphin. Today, there are believed to be around ten individuals remaining in the entire world. The porpoise was only discovered in 1958. 

Are narwhals endangered? 

Narwhals are considered to be near threatened. This means that it’s important to manage their populations, but they are not yet at a critical stage. 

Are walruses endangered? 

The IUCN describes the status of walruses as unknown. But, the biggest threat facing this animal is the loss of sea ice due to climate change. They are being forced to change their behavior due to the loss of their hunting territory. 

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