Population responses of the marine amphipod Corophium volutator (Pallas, 1766) to copper

The effects of copper concentrations on the life-history, growth and reproduction of Colophium volutator were investigated. Amphipods were exposed for 100 days to five sublethal copper concentrations (0.2, 0.4, 0.6, 0.8 and 1 mg l(-1)). Copper exposure significantly reduced the age-specific survivorship and longevity (P < 0.001). Life-expectancy differed at the various exposure concentrations of copper (P < 0.005). Growth was greatly reduced with copper exposure. The degree of reduction in growth rate increased with increasing metal concentration. Animals exposed to 0.2 mg Cu l(-1) exhibited a reduction of 2.4% in the specific growth rate (SGR), while those grown at 0.4, 0.6, and 0.8 mg Cu l(-1) exhibited reductions in SGR of 16.7, 23.5 and 20%, respectively: The length of the mature animals was also reduced following copper exposure (P < 0.05). Although sex ratio was not affected (P = 0.225), maturation and fertility were greatly reduced. Survival of ovigerous females and fertility were also affected by copper when mature animals were exposed to these concentrations. These results suggest that long-term exposure of C. volutator to low concentrations of copper could lead to a severe local population density decline because of the reduction of juvenile survivorship and fertility. Long-term exposure of C. volutator to higher concentrations of copper could have more serious consequences such as the local extinction of this species since the juveniles experienced such severe reductions in growth that they were unable to reach mature stage. (C) 1998 Elsevier Science B.V. All rights reserved.