In-field determination of nanomolar nitrite in seawater using a sequential injection technique combined with solid phase enrichment and colorimetric detection
- 作者：Guohe Chen ; Dongxing Yuan ; Yongming Huang ; Min Zhang ; Maria Bergman
- 关键词：Parasite infection ; Diplostomiasis ; Trematoda ; Competition ; Growth rate ; Fish farming
- 刊名：Analytica Chimica Acta
- 出版年：2008
- 期刊代码：2_00032670
- 类别：ch
- 出版时间：14 July 2008
- 卷：620
- 期：1-2
- 页码：82-88
- 文件大小：372 K
摘要
Effect of the eye fluke Diplostomum spathaceum on fish growth has remained somewhat unclear because 1) the question has not been subjected to experimental examination with treatment-control setup and 2) growth has not been related to the coverage of parasite-induced cataracts in a quantitative manner. We examined effects of the parasite on growth and competitive ability of whitefish (Coregonus lavaretus) in experimental conditions resembling those at fish farms by maintaining groups of exposed and control fish, as well as mixed groups from both treatments, under optimal conditions for 8 weeks. Contrary to our expectations, we did not observe differences in fish growth between the treatments. However, at the level of individual fish, parasite-induced cataracts had a negative effect on weight of the exposed fish but this took place only when the cataract coverage reached 100%in both eyes. No effect of the infection on competitive ability of fish was observed in mixed treatments which may be related to patterns of food distribution in the tanks or cues received by the fish from less infected conspecifics. Overall, the results suggest that effects of D. spathaceum on fish growth become apparent only in cases of very high cataract coverage, and that feeding regimes and the shape of the cataract coverage distribution in a fish group are important determinants of the magnitude of these effects.