REPRODUCTIVE STYLES AND LIFE-HISTORY VARIABLES RELATIVE TO EXPLOITATION AND MANAGEMENT OF SEBASTES STOCKS

被引:74
作者
LEAMAN, BM
机构
[1] Biological Sciences Branch, Pacific Biological Station, Fisheries and Oceans Canada, Nanaimo, V9R 5K6, British Columbia
关键词
ROCKFISH; LONGEVITY; REPRODUCTIVE VALUE; FISHERIES; SCORPAENIDAE;
D O I
10.1007/BF02296893
中图分类号
Q14 [生态学(生物生态学)];
学科分类号
071012 ; 0713 ;
摘要
The characteristics of lightly and heavily exploited Pacific ocean perch, Sebastes alutus, stocks are evaluated relative to the predictions of life history theory. These long-lived species (50-100 year lifespan) show limited phenotypic plasticity and have little buffering against the effects of reduced lifespan. Reduced stock abundance has generated some compensatory increase in growth rate. Length at first maturity varies only slightly with increased growth rate, although age at maturity may decrease by 1-4 years. Growth increases yield larger (15-20%) size at age and increased reproductive effort at younger ages, but lower size-specific fecundity for these faster-growing fish. This suggests an energy allocation protocol favouring growth over reproduction in these long-lived animals. Rockfishes have late recruitment to fisheries (ages 10-15), and the detection time for results of management actions is equally long. Their vulnerability to overfishing means that indices of population changes, more representative of fishing effects than the catch rate index presently used, are required. Reproductive value indices are shown to be extremely sensitive and continuous with population abundance changes. Their incorporation into monitoring programs would permit more timely evaluation of management actions. Management policies developed for shorter-lived species are shown to be inappropriate for rockfishes. The need for an improved match in the time frame of the species' life history, and that of management strategies, is stressed.
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页码:253 / 271
页数:19
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