Preferential food source utilization among stranded macroalgae by Talitrus saltator (Amphipod, Talitridae): a stable isotopes study in the northern coast of Brittany (France)

The importance of stranded macrophyte detritus as food sources for an amphipod inhabiting sandy beaches, Talitrus saltator, has been investigated by the use of stable isotopes (d13C, d15N) during summer and autumn 2000. The results showed that the different co-occurring stranded macrophytes, mostly macroalgae, had distinct d13C vs. d15N values. In addition, the study underlined the importance of Talitrus saltator as a key consumer of stranded macroalgal detritus. However, d13C vs. d15N strongly suggests a preferential utilization of Fucus serratus as a food source by Talitrus saltator within the available pool of detrital macroalgae, and the ability of this amphipod to use this detrital macroalgae without trophic mediation.