Partial migration, where migrant and resident organisms coexist within the same population, has been found in many fishes. Although it seems obvious that different life cycles exploit habitats and food webs differently, few assessments about the trophic consequences of partial migration are available. To unveil part of this complexity, we combined otolith chemistry with stable isotope analyses data for hind-casting Merluccius australis habitat use and diet composition at age. By providing detailed information about lifetime variability in diet, trophic position, and prey demand of four M. australis life-cycle types, we show that these groups feed differentially in estuarine and oceanic habitats throughout their ontogeny. Although trophic positions were similar between habitats for juvenile and subadults, substantial differences between life-cycle types were found regarding lifetime diet and trophic demand. Thus, the more abundant and heavily exploited oceanic stock of M. australis was heavily dependent of estuarine habitats within the Patagonian Fjords System, where it consumes large biomasses of Macruronus magellanicus, Pasiphaea, Sprattus fuegensis, and Euphausiidae at earlier stages. We show ignoring trophic consequences of partial migration and life-cycle diversity may produce highly biased results, both in terms of prey and habitat use, which appears critical for multispecies and ecosystem management approaches.

中文翻译：

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部分迁徙的营养生态：西北巴塔哥尼亚的南方墨鱼

在许多鱼类中发现了部分迁徙，其中迁徙生物和居民生物共存于同一种群中。尽管似乎很明显，不同的生命周期对栖息地和食物网的利用不同，但很少有人对部分迁移的营养后果进行评估。为了揭示这种复杂性的一部分，我们将耳石化学与稳定的同位素分析数据结合起来，用于后生南方古猿的栖息地使用和年龄的饮食组成。通过提供有关四个澳洲分枝M的饮食，营养位置和猎物需求的终生可变性的详细信息生命周期类型，我们表明这些群体在个体发育过程中在河口和海洋生境中的觅食不同。尽管青少年和亚成体栖息地之间的营养位置相似，但是在生命周期饮食和营养需求方面，生命周期类型之间存在很大差异。因此，越丰富和过度开采海洋股票M.芦苇在很大程度上取决于巴塔哥尼亚峡湾系统内河口的栖息地，它消耗了大量的生物质Macruronus magellanicus，Pasiphaea，黍fuegensis和Euphausiidae处于早期阶段。我们发现，忽略部分迁徙的营养后果和生命周期多样性可能会在猎物和栖息地使用方面产生高度偏差的结果，这对于多物种和生态系统管理方法而言至关重要。