Over the last two decades, declines in lake whitefish (Coregonus clupeaformis) recruitment and growth in many areas of the Laurentian Great Lakes have raised concerns about the status of this important species. Although Lake Superior populations have been less affected than those in other Great Lakes, these populations still face multiple threats. We characterized lake whitefish diets collected off the Keweenaw Peninsula between 2015 and 2017 and compared results to previous Lake Superior studies. We additionally estimated length-weight relationships to determine whether lake whitefish body condition (i.e., expected weight-at-length) had changed since the 1980s. Diet diversity was low, although individual specialization was moderate to high. Fish transitioned from consuming Diporeia in the spring to Mysis and fish eggs during fall and winter; sphaeriids composed 20–30% of diets across all seasons. Compared to findings for other Lake Superior regions, lake whitefish diets comprised lower percentages of high energy items (e.g., Diporeia, Mysis) and higher percentages of low energy items (e.g., sphaeriids). Expected weights in the 2000s and 2010s were lower in the 400- and 500-mm length groups but similar in larger lengths groups compared to the 1980s; condition was highest across all lengths in the 1990s. The observed decline in condition since the 1990s in the 400- and 500-mm length groups, in combination with possibly greater consumption of less energetically profitable items, suggests that lake whitefish <600 mm or preferred prey resources in this lake region may be experiencing stressors leading to condition declines, although what these stressors are remain unknown.

在过去的二十年中，劳伦山脉大湖许多地区的白鲑（Coregonus clupeaformis）募集和生长下降，引起了人们对该重要物种状况的关注。尽管苏必利尔湖地区的人口受灾程度不及其他大湖区，但这些人口仍然面临多重威胁。我们对2015年至2017年之间从基韦诺半岛（Keweenaw Peninsula）采集的白鲑鱼饮食进行了表征，并将结果与​​之前的苏必利尔湖研究进行了比较。我们还估算了长度与重量的关系，以确定自1980年代以来湖白鱼的身体状况（即预期的纵向重量）是否发生了变化。饮食多样性较低，尽管个体专长中等至较高。鱼从食用双孔菌过渡春季为Mysis，秋季和冬季为鱼卵；在整个季节中，鳞片类动物占饮食的20％至30％。与其他苏必利尔湖地区的调查结果相比，湖白鱼饮食中高能量食物（如双孢菌属，Mysis）所占的比例更低）和较低百分比的低能耗产品（例如，鳞片类动物）。与1980年代相比，在400毫米和500毫米长度组中，预期的重量在2000年代和2010年代较低，但在较大长度的组中相似。在1990年代，这种状况在所有长度上都是最高的。自1990年代以来观察到的长度在400毫米和500毫米的种群状况下降，再加上可能会大量消耗较低的能源效益项目，这表明该湖泊区域小于600毫米的白鲑或首选的猎物资源可能正在承受压力。尽管这些压力源尚不清楚，但导致病情下降。