Canadian Journal of Fisheries and Aquatic Sciences, Ahead of Print.
Fisheries management requires spatially congruent production and assessment areas. Canada’s Northern cod (Gadus morhua), initially considered a stock complex distributed from northern Labrador to the northern Grand Bank, had its northern boundary reduced to southern Labrador in the early 1970s. Spatial incongruence has resulted in spawning stock biomass (SSB) and recruitment (R) between historical and recent eras. To investigate temporal changes, four stanzas of SSB and R were derived from statistical Perron breaks. In stanza 1, the 1960s, spawning off northern Labrador coincided with higher SSB and R than in following stanzas from the 1970s onward. SSB–R relationships that include 1960s data do not represent potential production from a more southerly distributed stock. Loglinear models of R (density-dependent models did not improve fit) indicated SSB had greatest effect and, with indices of climate and south–north distribution, explained 86% of variance. Lack of density dependence suggests long-standing recruitment overfishing, making reference points problematic. SSB growth is suggested as an alternative management target. Rebuilding the Northern cod to historical abundance requires a full “portfolio” of spawning from northern Labrador to the Grand Bank (a remanaged 2+3KL stock). With a contracted range, lower production should be anticipated.

中文翻译：

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库存生产和评估领域的一致性？加拿大标志性北部鳕鱼的历史视角

加拿大渔业和水生科学杂志，印刷前。
渔业管理需要空间一致的生产和评估区域。加拿大北部鳕鱼（Gadus morhua）最初被认为是从拉布拉多北部到大银行北部分布的种群复合体，其北部边界在 1970 年代初期缩小到拉布拉多南部。空间不一致导致在历史和最近时代之间产生种群生物量 (SSB) 和补充 (R)。为了研究时间变化，SSB 和 R 的四个节来自统计 Perron 中断。在 1960 年代的第 1 节中，在拉布拉多北部产卵的同时，SSB 和 R 高于 1970 年代以后的后续节。包括 1960 年代数据的 SSB-R 关系并不代表更偏南分布的种群的潜在产量。R 的对数线性模型（密度相关模型没有改善拟合）表明 SSB 的影响最大，并且通过气候和南北分布指数，解释了 86% 的方差。缺乏密度依赖性表明长期的招募过度捕捞，使参考点成为问题。建议将 SSB 增长作为替代管理目标。将北部鳕鱼重建到历史丰度需要从拉布拉多北部到大银行的完整“组合”产卵（重新管理的 2+3KL 种群）。在合同范围内，预计产量会降低。建议将 SSB 增长作为替代管理目标。将北部鳕鱼重建到历史丰度需要从拉布拉多北部到大银行的完整“组合”产卵（重新管理的 2+3KL 种群）。在合同范围内，预计产量会降低。建议将 SSB 增长作为替代管理目标。将北部鳕鱼重建到历史丰度需要从拉布拉多北部到大银行的完整“组合”产卵（重新管理的 2+3KL 种群）。在合同范围内，预计产量会降低。