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(T/MF183) Effects of effluent exposure on different levels of functional organization in zebrafish (Danio rerio). Smolders, Roel1, Bervoets, Lieven1, De Boeck, Gudrun1, Blust, Ronny1, 1 ABSTRACT- Toxic exposure of organisms interferes with organismal integrity at the biochemical level and ultimately gives rise to effects at the individual level. This in turn will result in reduced ecologically relevant characteristics such as growth, reproduction and survival. A chronic toxicity test with zebrafish (Danio rerio) was conducted where fish were exposed to 50 %, 75 % and 100 % effluent for 28 days under flow through conditions. Effects of effluent exposure were determined on an organismal (condition, growth), physiological (respiration during swimming) and reproductive (spawning and hatching) level within the same population. Results indicate that the condition and growth of zebrafish is depressed by exposure to the effluent. Also, an increased oxygen consumption was found after 14, 21 and 28 days of exposure. Reproduction proved to correlate well with the condition of unexposed motherfish, and the number of eggs and larvae produced was significantly depressed by effluent exposure. The number of eggs and larvae produced in 100 % effluent showed a tendency to be lower than could be explained by the condition of the motherfish alone. These results indicate that the use of different ecologically relevant levels of organismal integrity provides a rational basis to establish cause-effect relationship in toxicity testing. The approach allows to quantify effects at different levels of organization but also reveals interactive effects across levels of organization. Key words: Whole Effluent Toxicity, Zebrafish, Reproduction, Condition |
