Abstract The invasive rainbow smelt (Osmerus mordax) was an abundant food source for Lake Winnipeg walleye (Sander vitreus), especially in the north basin of the lake, until the smelt’s collapse in approximately 2013. We quantified changing length-at-age (≈ growth rates) and relative mass (≈ body condition) in Lake Winnipeg walleye caught for a gillnet index data set. Here, walleye showed smaller length-at-age, particularly young fish in the north basin, over time. This approach to assessing growth suggests a constraint in the north basin fish, possibly a nutritional limitation between 2017 and 2018, that was not present in the south. We then analyzed a separate group of walleye (≥452 mm in fork length) sampled in 2017 as part of a large-scale tracking study, which had a similar slope in length-mass relationship to large walleye caught in that year for the gillnet index data. A panel of metabolites in whole blood samples associated with amino acid metabolism and protein turnover was compared. These metabolites revealed elevated essential amino acids in fish caught in the Dauphin River, and suggest that protein degradation may be elevated in north basin walleye. Therefore, based on both growth estimates and metabolites associated with protein balance, we suggest there were spatially distinct separations affecting Lake Winnipeg walleye with decreased nutritional status of walleye in the north basin of Lake Winnipeg being of particular concern.

中文翻译：

---

形态学和血液代谢物反映了温尼伯湖角膜白斑、Sander vitreus 之间最近的时空差异

摘要 入侵的彩虹鱼 (Osmerus mordax) 是温尼伯湖角膜白斑鱼 (Sander vitreus) 的丰富食物来源，尤其是在湖的北部盆地，直到 2013 年左右该鱼崩塌。我们量化了年龄变化长度 (≈生长率）和相对质量（≈ 身体状况）在温尼伯湖角膜白斑中捕获的刺网指数数据集。在这里，随着时间的推移，大眼鱼的年龄长度较小，尤其是北部盆地的幼鱼。这种评估生长的方法表明北部盆地鱼类存在限制，可能是 2017 年至 2018 年期间的营养限制，而南部则不存在。然后，作为大规模跟踪研究的一部分，我们分析了 2017 年采样的一组单独的角膜白斑（叉长≥452 毫米），对于刺网指数数据，它与当年捕获的大型角膜白斑的长度质量关系具有相似的斜率。比较了全血样品中与氨基酸代谢和蛋白质周转相关的一组代谢物。这些代谢物揭示了在多芬河捕获的鱼的必需氨基酸升高，并表明蛋白质降解可能在北盆地角膜白斑鱼中升高。因此，根据与蛋白质平衡相关的生长估计和代谢物，我们认为存在影响温尼伯湖角膜白斑鱼的空间上不同的分离，温尼伯湖北部盆地角膜白斑的营养状况下降尤其值得关注。这些代谢物揭示了在多芬河捕获的鱼的必需氨基酸升高，并表明蛋白质降解可能在北盆地角膜白斑鱼中升高。因此，根据与蛋白质平衡相关的生长估计和代谢物，我们认为存在影响温尼伯湖角膜白斑鱼的空间上不同的分离，温尼伯湖北部盆地角膜白斑的营养状况下降尤其值得关注。这些代谢物揭示了在多芬河捕获的鱼的必需氨基酸升高，并表明蛋白质降解可能在北盆地角膜白斑鱼中升高。因此，根据与蛋白质平衡相关的生长估计和代谢物，我们认为存在影响温尼伯湖角膜白斑鱼的空间上不同的分离，温尼伯湖北部盆地角膜白斑的营养状况下降尤其值得关注。