The Effect of Mercury on the Feeding Behavior of Fathead Minnows (Pimephales promelas)
Fathead minnows (Pimephales promelas) were exposed to mercury (1.69, 6.79, and 13.
57 Âµg/l HgCl2; 10 d exposure) and afterwards tested using various metrics of foraging
ability while feeding in a vegetated habitat. Among the foraging metrics were foraging
efficiency, capture speed, and the ability to learn and retain information regarding habitat
characteristics. Comparisons with control fish and fish from the two highest exposure
groups revealed consistent performance deficits in foraging efficiency and capture speed.
However, no treatment effects on learning were detected. In determining the underlying
proximate cause of the foraging deficits, it is believed that the greater pause time
exhibited by treatment fish while foraging was the main cause of treatment differences.
In the future, behavioral studies will continue to allow toxicity testing of environmentally
relevant variables such as those used by behavioral ecologists. Such tests, when
combined with tests of field collected specimens, could prove powerful in linking
laboratory toxicity to toxicity in wild populations.