American Plaice | Oceana Canada

Canadian Marine Life Encyclopedia

American Plaice

Hippoglossoides platessoides

Also known as

Dab, plaice, sole


Continental shelves of the Atlantic Ocean from the Arctic Circle to Rhode Island


Soft sandy or muddy bottoms

Feeding Habits

Ambush predator

Conservation Status



Order Pleuronectiformes (flatfishes); Family Pleuronectidae (right-eye flounders)


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When American plaice emerge from their eggs, they have a normal fish-shaped body. Like other flatfish, they develop their unique shape over time.  As they grow, their left eye starts to migrate over to their right side and their body begins to flatten. By the time they reach the juvenile stage and settle on the ocean floor, they will have assumed the classic flatfish shape. Their flattened body allows them to lie flush with the ocean floor and swim on their side, undulating just above the ground in search of their favourite foods. As adults, American plaice are known to be fairly adaptable to changes in prey availability; however they commonly feed on worms, molluscs, sea urchins, starfish, crustaceans and small fish. 

The two major populations of American plaice in Canada, the Maritime and the Newfoundland and Labrador populations, were both assessed by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) as threatened in 2009. The small Arctic population was assessed by COSEWIC as data deficient in 2009 as well. The two major populations were designated as threatened due to the dramatic population declines caused by overfishing during late 1900s. The Newfoundland and Labrador population saw a decline of 94-96 per cent over a 30-50 year period, while the Maritime population saw an average population decline of 76 Per cent. Despite this sever population decline, American plaice have not been assessed or listed under the Species-at-Risk Act (SARA) in Canada.