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Nutritional condition and reproductive success in wild fish populations
Lambert, Y.; Dutil, J.-D.; Ouellet, P. (2000). Nutritional condition and reproductive success in wild fish populations, in: Norberg, B. et al. (Ed.) Proceedings of the 6th International Symposium on the Reproductive Physiology of Fish, Bergen, Norway, July 4-9, 1999. pp. 77-84
In: Norberg, B. et al. (2000). Proceedings of the 6th International Symposium on the Reproductive Physiology of Fish, Bergen, Norway, July 4-9, 1999. International Symposium on the Reproductive Physiology of Fish, 6. Department of Fisheries and Marine Biology, University of Bergen: Bergen. ISBN 82-7461-048-2. 499 pp.
In: International Symposium on the Reproductive Physiology of Fish. Museo Nacional de Ciencias Naturales. , more
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| Authors | | Top |
- Lambert, Y.
- Dutil, J.-D.
- Ouellet, P.
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| Abstract |
The production of a large number of high quality eggs is important both to farmers and natural populations in the wild. Parental genes, fish size and nutritional status are known to have major effects on egg production. While broodstocks are carefully selected and benefit from a controlled environment resulting in high reproductive output, fish in the wild are exposed to a host of environmental factors that fluctuate in an uncontrolled manner. Species respond to this situation by using a number of different reproductive strategies. American eel and pink salmon which have high energy expenditures during the spawning period do not survive to a second reproduction. Lake whitefish and arctic chair, in contrast, may skip reproduction to enhance survival, and nutritional condition is thought to determine the length of the spawning interval. Atlantic cod usually reproduce annually when mature. However, nutritional condition may bear upon their reproductive success. While cod with fast growth rates do not experience poor individual condition, strong seasonal variations in condition occur in slow growing cod. We have examined the impact of poor condition on the survival and reproductive energetics of cod in the northern Gulf of St. Lawrence during a period when stock production was declining, presumably in response to a deteriorating environment. During that period, cod condition during spawning declined to levels close to the range where energy reserves are completely exhausted. Fecundity and total egg dry weight were significantly lower in poor condition females, particularly those of smaller size. Despite lower fecundity, estimated loss in somatic energy during reproduction was proportionally greater for cod with poorer levels of condition. This lower egg production per unit of spawning stock biomass may have seriously impeded the reproductive potential of the stock in the late 1980s and in the 1990s. The relationship between size of the spawning stock and recruitment to the fishery may thus vary considerably with the nutritional condition of the spawners. |
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