Effects of temperature and salinity on life history of the marine amphipod Gammarus locusta. Implications for ecotoxicological testing.

The life history of Gammarus locusta was analysed in the laboratory under the following temperature and salinity combinations: 20 degrees C-33/1000, 15 degrees C-20/1000 and 15 degrees C-33/1000 (reference condition). Life history analysis comprised survival, individual growth, reproductive traits and life table parameters. Compared to 15 degrees C, life history at 20 degrees C was characterised by at least a four-week reduction in the life-span, lower life expectancy, shorter generation time, faster individual growth, anticipation of age at maturity and higher population growth rate. These temperature effects constituted an acceleration and condensation of the life cycle, compared to the reference condition. Concerning salinity effects, with few exceptions, results show that overall this amphipod life history did not differ significantly between the salinity conditions tested. Regarding ecotoxicological testing implications, findings from this study indicate that the range of temperature and salinity conditions acceptable for testing was substantially expanded both for acute and chronic assays. A temperature of 20 degrees C or higher (for a salinity of 33/1000) is suggested for routine chronic sediment toxicity testing with G. locusta, in order to reduce the life cycle and consequently improve cost-effectiveness and standardisation. Results also suggest that a multiple-response approach, including survival, growth and reproduction, should be applied in chronic toxicity tests.