Lipid indicators of the diet of the sympagic amphipod Gammarus wilkitzkii in the Marginal Ice Zone and in open waters of Svalbard (Arctic)

Triacylglycerols were the major lipid and wax esters a minor lipid in the A rctic autochthonous, sympagic amphipod, Gammarus wilkitzkii, from less than 1 year old to 3 years old in the Marginal Ice Zone around Svalbard. The fa tty acids of the triacylglycerols, especially in young G. wilkitzkii, were mainly characteristic of diatoms and, to a lesser extent, flagellates. Smal l amounts of 20:1n-9 and 22:1n-11 fatty acids characteristic of calanoid co pepods were also present in the triacylglycerols in young G. wilkitzkii fro m the Marginal Ice Zone and the amounts of both of these fatty acids increa sed in the triacylglycerols as the animals matured. G. wilkitzkii in open w aters in Kongsfjord had minor amounts of triacylglycerols rich in 20:1n-9 a nd 22:1n-11 and major amounts of wax esters characteristic of calanoid cope pods. We conclude that young G. wilkitzkii in the Marginal Ice Zone feed pr edominantly on ice algae and that they consume increasing amounts of calano id copepods as they mature, albeit with ice algae remaining a prominent com ponent of their diet. In open waters, young G. wilkitzkii consume mainly ca lanoid copepods.