Polar cod
| Polar cod | ||||||||||||
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Polar cod ( Boreogadus saida ) |
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| Boreogadus saida | ||||||||||||
| Lepechin , 1774 |
The Arctic cod ( Boreogadus saida ) belongs to the family of cod ( Gadidae ). It is closely related to the cod ( Gadus morhua ) or cod .
Distribution and Biology
The polar cod is at home in the cold waters of the Arctic polar sea . This species is circumpolar , i. i.e., it inhabits the North Atlantic as well as the North Pacific . The polar cod lives, grows and reproduces in salt water with a temperature of 0 ° C or below. He alternates between a life directly below the surface of the sea and a life above the sea floor.
The one- to two-year-old polar cod are 6 to 17 cm long and are largely bound to the sea ice. They live in hollows and crevices in the sea ice and between ice floes. Here you will find protection from predators and their predatory parents, as well as a rich supply of animal plankton .
The older fish live in shallow waters above the sea floor or in deeper, free water layers up to 700 m. Here they feed on small, freely swimming crabs such as amphipods or krill . Only at the age of four do they reach a body length of approx. 20 cm and become sexually mature. When fully grown, they can reach a body length of 25 cm to 40 cm, depending on the region.
ecology
The polar cod is an important part of the northern polar ice fauna . Its predators are sea birds, marine mammals and various types of fish. This makes it the most important species in the polar sea that connects the flow of energy between planktonic organisms and vertebrates living on the ice .
As a food competitor to capelin ( Mallotus villosus ) and with common predators , the polar cod population declines sharply in some years. The reason is the overfishing of the capelin stock, as the capelin's main predators now use polar cod as food.
The polar cod is considered to be endangered by the effects of climate change in the event of non-compliance with the 1.5 degree target .
Individual evidence
- ↑ Flemming T. Dahlke, Martin Butzin, Jasmine Nahrgang, Velmurugu Puvanendran, Atle Mortensen, Hans-Otto Pörtner , Daniela Storch (2018). Northern cod species face spawning habitat losses if global warming exceeds 1.5 ° C. Science Advances , 4 (11), doi: 10.1126 / sciadv.aas8821
Web links
- Polar cod on Fishbase.org (English)