Effects of 3,4-dichloroaniline on fish populations. Comparison between r- and K-strategists: A complete life cycle test with the guppy (Poecilia reticulata)

Abstract

In order to compare data derived from life cycle tests with zebrafish (Brachydanio rerio Ham.- Buch.), an r-strategist, with data of fish exhibiting a differing strategy of reproduction, a complete life cycle test with the guppy (Poecilia reticulata Peters) was performed with the chemical 3,4-dichloroaniline. The generation of guppies exposed during the whole life span (FI) reacted with more sensitivity than the generation exposed only as adults (Fo): Growth of adult females and reproduction was reduced significantly at 200 Μg/L in Fo, and even at 2 and 20 Μg/L in FI. The survival rates of the early life stages were not influenced at the tested concentrations. There is hardly any difference in acute toxicity of adult guppies and zebrafish. With regard to chronic toxicity at lower concentrations, however, both species react differently: Guppy reproduction is the most sensitive parameter (zebrafish reproduction is not influenced at 200 Μg/L), but zebrafish larvae react most drastically (no survival of larvae at 200 Μg/L in FI, reduced survival of larvae at 20 Μg/L in FII, Nagel 1988). Consequently, zebrafish cannot be a valid model for assessment of the effects of chemicals on populations with differing reproductive strategies.