Ecological studies have traditionally treated fish species or populations as homogenous groups; however, numerous studies have shown that intrapopulation variation in resource use is widespread. Within‐species diet differences are evident in small and large freshwater systems and may influence trophic and population dynamics. In a previous study of young yellow perch, spatial intrapopulation diet variation was observed for stomach contents, a relatively short‐term diet indicator. In the current study, we build upon the earlier study of yellow perch in Saginaw Bay, Lake Huron, and assess patterns of long‐term diet indicators (stable isotopes and morphology) to assess consistency of diet variation over time and improve characterisation of trophic differences among sites. Specifically, we analysed soft tissue samples for carbon (δ¹³C) and nitrogen (δ¹⁵N) isotope ratios and used geometric morphometrics to describe morphological variation of young yellow perch. While both isotopes displayed significant spatial differences, δ¹⁵N values demonstrated a much clearer separation among sites, with greater δ¹⁵N values for yellow perch collected closer to the mouth of the Saginaw River. Morphological variation also was more apparent among sites rather than between years or months, with more streamlined yellow perch morphologies evident at sites where they consumed high proportions of zooplankton relative to benthic invertebrates. Somewhat unexpectedly, soft tissue δ¹³C values varied strongly between the two study years; however, the ultimate cause of such interannual variation in δ¹³C is unclear. These long‐term indicators showed consistent spatial differences, which suggests that individual fish are using resources at a particular site long enough to reflect a stable isotope or morphological signal. Yellow perch production at different locations seemingly relies on different prey resources, suggesting that annual variation in dominant trophic pathways may alter the performance of yellow perch at each location.

中文翻译：

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稳定的同位素和形态揭示了幼体非营养鱼类的营养依赖性的空间和年度格局

生态学研究传统上将鱼类或种群视为同类。但是，许多研究表明，人口内部资源利用的差异是普遍存在的。在大型和淡水系统中，种内饮食差异明显，并且可能影响营养和种群动态。在先前对年轻黄鲈的研究中，观察到胃内成分的空间内饮食差异是相对短期的饮食指标。在当前的研究中，我们基于对休伦湖萨吉诺湾黄鲈的早期研究，并评估了长期饮食指标（稳定的同位素和形态）的模式，以评估随时间变化的饮食一致性，并改善营养差异的特征。网站之间。具体来说，我们分析了软组织样本中的碳（δ¹³ C）和氮（δ ¹⁵ N）同位素比率和使用的几何形态测量来描述年轻黄鲈的形态变异。虽然这两种同位素显示显著空间差异，δ ^15个N个值表明站点之间更清晰的分离，以更大的δ ^15个用于黄色鲈鱼收集更靠近萨吉诺河口的N个值。地点之间的形态变化也更为明显，而不是数年或数月之间。在它们栖息的浮游动物相对于底栖无脊椎动物的比例较高的地点，流线型的黄色鲈鱼形态更为明显。多少有些出人意料，软组织δ ¹³在这两个学习年之间，C值差异很大。然而，这样的际变化的在δ的最终原因¹³ C是不清楚。这些长期指标显示出一致的空间差异，这表明个别鱼类在特定地点使用资源的时间足够长，以反映稳定的同位素或形态信号。不同位置的黄鲈生产似乎依赖于不同的猎物资源，这表明优势营养途径的年度变化可能会改变每个位置的黄鲈的性能。