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Tropentag, October 5 - 7, 2004 in Berlin

"Rural Poverty Reduction
through Research for Development and Transformation"


Survival and Growth Comparisons of Rainbow Trout Populations (Oncorhynchus mykiss) under the Specific Environmental Conditions in Northern Thailand

Prasan Pornsopin1, Gomut Unsrisong1, Therdchai Vearasilp2, Udo ter Meulen3, Gabriele Hƶrstgen-Schwark4

1Chiang Mai Inland Fisheries Research and Development Center, Department of Fisheries, Thailand
2Chiang Mai University, Department of Animal Science, Thailand
3Georg-August-Universität Göttingen, Institute of Animal Physiology and Nutrition, Germany
4Georg-August-Universität Göttingen, Institute of Animal Husbandry and Genetics, Germany


Abstract


A comprehensive performance comparison of different rainbow trout populations was conducted at Doi Inthanon Fisheries Research Unit over two experimental series in order to identify genetic differences between populations under the specific production conditions of Northern Thailand. Eyed eggs of seven populations were transferred from the Experimental Trout Station Relliehausen, University of Göttingen, to Doi Inthanon Fisheries Research Unit. Here a special system for population testing in trout was developed. This consisted of separate hatching and rearing of populations till the end of the first feeding stage under two water temperature regimes (11°C, 14°C), further separate rearing of each population up to markable size under ambient water temperatures and common fattening up to pan-size weight. This weight was achieved 8 months after hatching. Whereas no significant differences between populations were found with regard to hatching rates under a temperature regime of 11°C, significant differences between populations were observed for hatching rates under the higher water temperature regime. Here hatching rates ranged from 67% to 95% between populations. Survival rates till the end of first feeding (range from 88% to 97%) were similar under both temperature regimes and showed significant differences between populations. Survival rates from the first feeding stage to rearing weights of markable size were high and between 96% to 99% with no significant differences between populations. Thereafter till pan size weight, survival rates of populations differed between 88% and 98% . Significant differences of up to 22% for rearing and fattening weight were observed between populations. The observed differences in survival and growth performance between populations were quite distinct. It is therefore apparent that careful selection of stock to be used for both production and breeding is of significant importance.


Keywords: Aquaculture, Thailand, performance comparison, rainbow trout populations


Contact Address: Gabriele Hörstgen-Schwark, Georg-August-Universität Göttingen, Institute of Animal Husbandry and Genetics, 37075 Göttingen, Germany, e-mail: ghoerst1@gwdg.de


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