SIMPLE SIZE-STRUCTURED MODELS OF RECRUITMENT AND HARVEST IN PACIFIC SALMON (ONCORHYNCHUS SPP)
SIMPLE SIZE-STRUCTURED MODELS OF RECRUITMENT AND HARVEST IN PACIFIC SALMON (ONCORHYNCHUS SPP)
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DOI：
10.1139/f94-062
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发表时间：
1994-03-01
影响因子：
2.4
通讯作者：
PETERMAN, RM
中科院分区：
文献类型：
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作者：
FORBES, LS;PETERMAN, RM
越来越多的证据表明，在太平洋鲑鱼（Oncorhynchus spp.）中，除了繁殖力之外，繁殖成功的因素还取决于体型。然而，设定逃逸目标的管理者通常根据产卵鱼总数、雌性产卵鱼数量或给定产卵鱼平均大小的潜在卵沉积来估计种群的繁殖潜力。因此，产卵鱼大小组成的年际变化可能会导致评估繁殖潜力时出现错误。在这里，我们开发了招募和收获模型，并确定最佳的尺寸选择性收获策略。这些最佳策略的范围从当前的大鱼收获（捕获大于平均水平的鱼，留下较小的鱼产卵）到小鱼收获，反之亦然。如果随着成年雌性体长的增加，个体产卵鱼的体重 (M) 增长速度快于繁殖成功率 (RS)（例如，如果仅卵的数量最能衡量 RS），则当前大鱼收获可实现可持续生物量产量最大化。然而，如果 RS/M 随着雌性体长的增加而增加（例如，如果卵的总生物量最好地衡量 RS），那么小鱼收获可以最大限度地提高可持续产量。有证据表明，一些鲑鱼种群表现出后一种模式。因此，捕捞大鱼可能会产生次优产量。
Growing evidence suggests that in Pacific salmon (Oncorhynchus spp.), components of reproductive success besides fecundity are size dependent. However, managers setting escapement goals usually estimate reproductive potential of a stock in terms of total number of spawners, number of female spawners, or potential egg deposition given a mean size of spawners. Interannual variation in size composition of spawners may thus result in errors in assessing reproductive potential. Here, we develop models of recruitment and harvest and determine optimal size-selective harvesting strategies. These optimal strategies range from the current large-fish harvests (larger-than-average fish are caught, leaving smaller fish to spawn) to small-fish harvests, where the reverse is true. If the body mass (M) of individual spawners increases more rapidly than reproductive success (RS) with respect to increasing length of adult females (e.g., if number of eggs alone best measures RS), then sustainable biomass yield is maximized by the current large-fish harvest. However, if RS/M increases with increasing length of females (e.g., if total biomass of eggs best measures RS), then small-fish harvest maximizes sustainable yield. Evidence suggests that some salmon populations show this latter pattern; thus, large-fish harvests may generate suboptimal yields.