Influence of Temperature on the Survival, Growth and Sensitivity of Benthic Amphipods, Mandibulophoxus mai and Monocorophium acherusicum

Abstract

A series of experiments was conducted to evaluate the effects of temperature on the survival, growth and sensitivity of the benthic amphipods, Mandibulophoxus mai and Monocorophium acherusicum, which have been recently developed as new sediment toxicity testing species in Korea. The biological performance for each amphipod species was determined by the survival and growth rates at different water temperatures. The influence of temperature on the sensitivity to reference toxicant, Cd, was determined by the comparison of survival rates of amphipods exposed to control and Cd-spiked seawater at different temperatures. Temperature significantly influenced on the survival, growth and Cd sensitivity of both amphipods. Tolerable ranges of temperature for the >80% individuals of both M. mai and M. acherusicum with sediment substrates wee mostly overlapped (13 to 22℃). The daily growth rates of M. mai and M. acherusicum increased proportionally with temperature up to 20℃ and 25℃, respectively. Similarly, the sensitivities of M, mai and M. acherusicum to Cd increased with temperature up to 20℃ and 15℃, respectively. Overall results showed that temperature is a substantially important factor potentially influencing the results of lethal and sublethal bioassays using the amphipods. Therefore, defining the adequate ranges of experimental temperature for the toxicity testing species is the pre-requisite for the development of standardized bioassay protocols.