The development of biochemical and visible genetic markers and their potential use in evaluating interaction between cultured and wild fish populations

Large-scale fish farming, stock enhancement , and sea ranching programmes may cause unwanted genetic changes in wild populations. Loss of genetic variability has been observed in hatchery populations, but such changes are very difficult to detect in wild fish stocks. Detai led studies of gene flow can be carried out by releasing genetically tagged fish. In order to do this, the first step is to produce a broodstock which possesses a unique genetic marker for the species in question. The development of a genetically tagged strain of cod (Gadus morhua L.), being homozygote for a rare allele, is described. A visible genetic marker in brown trout (Salmo trutta L.) has recently been discovered. Such strains offer the possibility to perform gene flow experiments in order to study interaction between escaped farmed or released fish and natural populations.

This article is part of Marine Science Symposia Volume 192 - "The ecology and management aspects of extensive mariculture". To access other articles from this volume, please use the link to the volume on the upper right hand side.