Feeding strategy assessment through fatty acid profiles in muscle of adults sea lamprey from the Western Iberian Coast

Abstract

Fatty acid signature of sea lamprey Petromyzon marinus (L.) muscle were used as a tool to detect feeding strategies used during the species parasitic marine trophic phase. Adult sea lampreys were collected near the river mouth of six Portuguese river basins (i.e. Minho, Lima, Douro, Vouga, Mondego and Tagus) and muscle fatty acid profile characterized. The analysis on fatty acid composition of muscle neutral lipids showed the formation of two groups which pointed out that two feeding strategies may have been used by sea lampreys during the parasitic phase, based on the availability of ω-3 and ω-6 PUFA and on phytoplankton/zooplankton and bacterial detritus contribution in the sea lamprey host preferences. Two distinct lipid profiles were observed, probably related with two different trophic approaches, one typical of a top predator of a marine food web with a planktonic support, and the other much more diverse, including the same planktonic markers, together with biochemical clues that probably resulted from a parasitic phase that targeted directly fish consumers of detritus and benthic algae, and/or the predation of fish from a food web with a detritivorous base.