ABSTRACT: The aim of this study was to evaluate the effect of environmentally realistic egg loadings of the polychlorinated biphenyl Aroclor 1254 on the subsequent growth and behavioural survival skills of Atlantic croaker Micropogonias undulatus larvae. Adult fish were given a dietary administration of 0 (control) or 0.4 (dosed) mg Aroclor 1254 kg^-1 fish d^-1 for 2 wk during the final stages of gonadal recrudescence. Fertilised eggs collected from control and dosed adults immediately after spawning contained 0 and 0.66 µg Aroclor 1254 g^-1 egg, respectively. Growth rate (increase in total length) of dosed larvae was significantly lower than that of control larvae between 2 and 13 d post-hatching, with dosed larvae showing a 4 d delay in attaining the same size as control larvae. Behavioural assays were conducted to evaluate survival skills of larvae on Days 5 (complete yolk absorption), 9 (complete oil globule absorption), and 13 (larva wholly dependent on exogenous food sources) post-hatching. Survival skills examined were potential foraging rate (routine swimming speed and activity) and the response to a startle (transient vibratory stimulus) stimulus. Routine swimming speed and activity were similar for control and dosed larvae. There was a significant dose x age interaction in the responses of the control and dosed larvae to a vibratory stimulus. The percentage of control larvae responding to the stimulus, and their average and maximum burst speeds, increased with age. In contrast, no such age-related response was found in the dosed larvae. The results indicate that environmentally realistic body burdens of Aroclor 1254 transfer to the eggs and larvae, reducing their growth rates and impairing their startle responses, possibly making the larvae more susceptible to predation.

KEY WORDS: Endocrine disrupting chemicals · Polychlorinated biphenyls · Atlantic croaker · Fish larvae · Swimming activity · Predator avoidance · Sublethal effects · Growth

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Published in MEPS Vol. 252 (2003) on April 30
Print ISSN: 0171-8630; Online ISSN: 1616-1599. Copyright © Inter-Research, Oldendorf/Luhe, 2003