Excreted pharmaceuticals are leaking out into aquatic environments via effluent water where they are hypothesized to be potent enough to alter fish behavior. Central for this hypothesis is oxazepam, an anti-anxiety drug that have been shown to make fish behave more bold, more active, and less social. However, some laboratory trials have also failed to find these effects and have been poor predictors of fishes’ behavior in situ. The aims of my meta-analysis were; i) investigate the strength of oxazepam induced behavior changes in wild-caught fish, and ii) assess eventual impact of citation bias (i.e., that researcher prefer citing studies showing effects) on published literature relating to oxazepam induced behavior changes. I found, when combining existing literature on oxazepam impact on wild caught fish behavior, that exposure concentrations ranging between 0.5-100µg/L, did only change the activity (increased) of the fish. In high (>100 µg/L) concentration exposures activity and boldness increased, and sociality decreased as previously suggested. I also noticed a significant citation bias, where studies showing effects of oxazepam on behaviors were more frequently cited. Several studies report absence of behavior effects caused by oxazepam in controlled laboratory trials, despite using >1000 times higher concentrations that ever been measured in fresh water. Therefore, I find it unlikely that this drug has strong effects on fish in nature. Citation biases towards studies showing effects seems likely to have had a strong influence on the current notion that oxazepam is altering fish behavior.

Graduate