Meeting Abstract
Recent studies have documented the widespread occurrence of human pharmaceuticals in aquatic ecosystems. These chemicals or active metabolites may persist in the environment for months or years and have been shown to have adverse effects in numerous aquatic species. Our studies examined the effects of chronic low-level exposure to fluoxetine on behavior and growth following molting in the crayfish Orconectes rusticus. Fluoxetine, a widely prescribed antidepressant, is a serotonin reuptake inhibitor which alters levels of serotonin in synapses. Upon collection, male Form II crayfish (N = 75) were weighed and measured (carapace and chela length) and placed individually in water containing 0, 2, 20, 200, or 500 µg/L of fluoxetine. Prior to and following a two-week long exposure to fluoxetine, crayfish were tested in an open field arena to assess locomotion, exploration, and sheltering behavior. Animals were then held in their assigned dose of drug until each completed the molt to Form I; two weeks after molting each was again weighed and measured. In the open field tests, crayfish exposed to fluoxetine displayed significant increases in locomotion and decreases in sheltering behavior at concentrations at and above 2 µg/L. Timing of the molt was not affected by fluoxetine, but weight gain following the molt to Form I was significantly greater in animals exposed to fluoxetine at 500 µg/L and a similar tendency occurred at lower concentrations. In crayfish, serotonin acts both as a hormone and a neurotransmitter and we consider our results in the light of serotonin’s effects on molting, growth, and behavior in crustaceans.
