Greenland shark: high levels of long-lived pollutants

The Green­land shark is the unknown big ani­mal in mari­ne arc­tic eco­lo­gy. Until recent­ly, sci­en­tists have not spent too much atten­ti­on to this lar­ge shark, and litt­le is accor­din­gly known about them. But during a sci­en­ti­fic catch in Kongsfjord some years ago, sur­pri­sing num­bers were caught: dozens of sharks in a short time. They can be up to 7 m long, which places them among­st the lar­gest sharks in the world.

Sur­pri­sing was not only the num­ber of sharks pre­sent in the bot­tom waters of Kongsfjord, but also the high levels of long-lived envi­ron­men­tal toxins, which equal the high con­cen­tra­ti­ons sad­ly known from polar bears in Spits­ber­gen.

Ano­ther sur­pri­se was their diet: the sto­mach con­tent was most­ly fish and seals. Appear­ent­ly, they are effi­ci­ent hun­ters and not just sca­ven­gers, as had been belie­ved until then. The diet is likely to be the reason for the high levels of con­ta­mi­nants, which accu­mu­la­te through the food chain and over time. The long life span of Green­land sharks may accor­din­gly be ano­ther con­tri­bu­ting fac­tor to the high level of con­ta­mi­na­ti­on. During the rese­arch catch, the big­gest indi­vi­du­al caught was as hea­vy as 700 kg, but not even old enough to repro­du­ce.

Source: Nor­we­gi­an Polar Insti­tut

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