Abstract The southern hake, Merluccius australis, is one of the most important marine fishery resources in Chilean Patagonia. However, little is known about its early life history, especially the transport of eggs and larvae and the connectivity between spawning and nursery areas. An individual-based model (IBM) of the early life stages of M. australis, coupled to a hydrodynamic model, was used to track virtual individuals released from known spawning locations and identify potential nursery areas. The simulations were used to assess connectivity and retention of M. australis eggs and yolk-sac larvae within (and between) the continental shelf (offshore) and the inner sea (inshore) zones. The inshore zone included two spawning and nursery areas (Inner Sea of Chiloe (ISCh), Inner Sea of Moraleda Channel ISM)) and the offshore zone included three spawning and nursery areas (Guafo Island, Guamblin Island, and the Taitao Peninsula). The hydrodynamic model was validated using available observations (oceanographic surveys and the World Ocean Atlas 2018) for winter and spring, periods during which M. australis reproductive activity peaks. The IBM reproduced well the observed seasonal variability of egg and larval distributions. Individuals from the offshore spawning areas had low connectivity with those in the inshore nursery areas in winter and spring. However, individuals from the inshore spawning areas showed a high degree of connectivity with one of the offshore nursery areas (Guafo) during winter and spring, but low connectivity between the inshore ones (ISCh and ISM). Guamblin (in winter) and ISCh (in spring) were the most important retention areas. A conceptual model is proposed to represent the connectivity in early developmental stages between the spawning and nursery areas of M. australis: ichthyoplankton is transported from inshore to offshore in winter when little spawning occurs inshore, but not in spring when spawning and retention increases inshore. Retention in the offshore zone in winter is significant, with almost no connectivity with the inshore zone. Since the main spawning of the species occurs in winter in the offshore zone and secondarily in the inshore zone in spring, the seasonal differences in dispersal patterns seem to be part of the reproductive strategy of the species, which apparently confers advantages for the offspring by promoting development in the most advantageous feeding environment for each season (offshore in winter and inshore in spring).

中文翻译：

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智利巴塔哥尼亚北部无须鳕的早期生活阶段的连通性

摘要 南部无须鳕，Merluuccius australis，是智利巴塔哥尼亚最重要的海洋渔业资源之一。然而，对其早期生活史知之甚少，尤其是卵和幼虫的运输以及产卵区和育苗区之间的连通性。M. australis 早期生命阶段的基于个体的模型 (IBM) 与流体动力学模型相结合，用于跟踪从已知产卵地点释放的虚拟个体并确定潜在的育苗区。模拟用于评估大陆架（近海）和内海（近海）区域内（和之间）的澳大利亚金龟子卵和卵黄囊幼虫的连通性和保留。近海区包括两个产卵和育苗区（奇洛埃内海（ISCh），莫拉莱达海峡内海（ISM））和近海带包括三个产卵和育苗区（瓜佛岛、瓜布林岛和台涛半岛）。使用冬季和春季的可用观测（海洋学调查和 2018 年世界海洋地图集）验证了水动力模型，这两个时期是澳大利亚 M. australis 繁殖活动的高峰期。IBM 很好地再现了观察到的卵和幼虫分布的季节性变化。冬季和春季，离岸产卵区的个体与近岸育苗区的个体的连通性较低。然而，来自近海产卵区的个体在冬季和春季与近海育苗区之一（Guafo）表现出高度的连通性，但近海产卵区（ISCh和ISM）之间的连通性较低。Guamblin（冬季）和 ISCh（春季）是最重要的保留区。提出了一个概念模型来表示 M. australis 产卵区和育苗区之间早期发育阶段的连通性：浮游鱼类在冬季沿海产卵很少时从近海运输到近海，但在春季沿海产卵和滞留量增加时则不然。冬季在近海区的滞留量很大，与近海区几乎没有连通性。由于该物种的主要产卵发生在冬季近海地区，春季次要发生在近海地区，散布模式的季节性差异似乎是该物种繁殖策略的一部分，