Effects of Different Salinities on Juvenile Growth ofGammarus aequicauda(Malacostraca: Amphipoda)

Abstract

Gammarus aequicaudais a euryhaline amphipod that is a common inhabitant of brackish environments of the Mediterranean Sea. In the Ebro delta, the population density ofG. aequicaudais highly variable throughout the year. The main objective of this study is to investigate the effect of salinity on the growth ofG. aequicaudajuveniles.G. aequicaudaembryos and juveniles can survive and grow in the laboratory between 2 psu and 40 psu salinity, depending on the previous acclimation period for the reproductive individuals. Adults acclimated at 34 psu produced embryos and juveniles that survived and developed at salinities between 9 psu and 40 psu; adults acclimated at 9 psu produced embryos and juveniles that could develop in oligohaline conditions. The lower growth rate values were 10.9 μm d−1and 13.5 μm d−1at 40 psu and 2 psu, respectively, with the higher values of 18.0 μm d−1and 18.5 μm d−1at 19 and 34 psu, respectively.