Potential genetic interactions between reared and wild fish in Europe, with particular emphasis on Atlantic salmon
Cross, T.F. (1992). Potential genetic interactions between reared and wild fish in Europe, with particular emphasis on Atlantic salmon, in: De Pauw, N. et al. (Ed.) Aquaculture and the Environment: reviews of the International Conference Aquaculture Europe '91, Dublin, Ireland, June 10-12, 1991. EAS Special Publication, 16: pp. 299-308 In: De Pauw, N.; Joyce, J. (Ed.) (1992). Aquaculture and the Environment: Reviews of the International Conference Aquaculture Europe '91, Dublin, Ireland, June 10-12, 1991. Special Publication European Aquaculture Society, 16. European Aquaculture Society: Gent. ISBN 90-71625-10-9. 536 pp., more In: Special Publication European Aquaculture Society. European Aquaculture Society: Bredene. ISSN 0774-0689, more |
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| Abstract | The challenge facing aquaculturists is to maintain healthy wild fish populations, while ensuring growth of the industry. Reared fish can be introduced into the wild purposefully via stocking or accidentally via escapes from farms or straying from ranching operations. Concern is being expressed about a number of genetic aspects of such interactions, viz. 1) reared and wild fish of the same species might interbreed and their offspring could be less fit than the natives leading to a decline in productivity; 2) reared salmonids might breed later than their wild conspecifics thus overcutting redds and leading to a wild population decline by substantially increasing inbreeding; 3) resistant reared fish might transmit diseases to susceptible wild populations; and 4) detrimental inter-specific hybridization could occur. Most studies of wild population structure and of reared lines have utilized the biochemical genetic techniques of protein electrophoresis and, more recently, of DNA analysis. It is known, for example, that amongst wild salmonids, genetically-distinct non-interbreeding populations occur in each water body. Also, reared lines often differ from their wild founder populations, in terms of genetic composition and reduced genetic variability. The reasons for genetic changes in reared lines are inbreeding from the use of insufficient broodstock numbers and artificial selection. Very little is yet known about actual genetic interactions, but theoretically many of these could be damaging to wild populations. Stocking requires better planning and monitoring and the use of native of near native donor stock to ensure success and limit the environmental impact. Ranching also requires better planning and it has been shown that the use of native reared stock will minimize straying. In farming, escapes may be minimized by matching equipment to site conditions and their genetic effect eliminated by using sterile stock. |
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