Understanding factors like fish size and condition can be crucial to fisheries management. In the Great Lakes, long-term observations of these factors are used to describe the effects of ecosystem dynamics on fish ecology. Considering the diversity of available benthic habitat and dynamic environmental conditions in the nearshore zone of Lake Michigan, we sought to understand the variability in length-at-age and condition of yellow perch and round goby, two important members of the nearshore fish community. We measured these metrics from both species captured in gillnets across three locations in Illinois waters of southwest Lake Michigan from June through October 2008–2012 and related the spatiotemporal differences seen to observed variation in temperature, prey abundance, and competitor abundance. Yellow perch length-at-age varied annually for all three age-classes, with differences relating to thermal regime (age-0 and age-2) and alewife abundance (age-1). Yellow perch condition, measured as residual weight, varied spatially and annually, showing a negative relationship with round goby abundance. Round goby length-at-age was greater at the southern location, likely due to warmer temperatures, while condition was greater at the rockier location. In general, model selection analysis revealed several potential relationships between the relative abundances of competitor species and length and condition of yellow perch and round goby, while prey abundance may be related to round goby condition. These results demonstrate the importance of understanding the diversity in nearshore habitats and the influence of this diversity on factors affecting fish production, including size and condition, in southwest Lake Michigan.

了解鱼类大小和状况等因素对于渔业管理至关重要。在大湖地区，对这些因素的长期观察被用来描述生态系统动力学对鱼类生态的影响。考虑到密歇根湖近岸带可用底栖生境的多样性和动态环境条件，我们试图了解近岸鱼类群落的两个重要成员黄鲈和圆虾虎鱼的成年时长和条件的变化。我们从2008年6月至2008年10月至西南密歇根湖伊利诺伊州水域的三个地点的刺网中捕获的两种物种，测量了这些指标，并将时空差异与观测到的温度，猎物丰度和竞争者丰度的变化相关联。这三个年龄段的黄鲈年龄年龄每年都在变化，与热状况（0岁和2岁）和芦荟丰度（1岁）有关。黄色鲈鱼的状况，以剩余体重来衡量，在空间上和每年变化，与圆形虾虎鱼的丰度呈负相关。在南部地区，圆虾虎鱼的成年期更长，这可能是由于温度升高所致；而在较岩石的地区，情况则更大。一般而言，模型选择分析揭示了竞争者物种的相对丰度与黄鲈和and虾的长度和状况之间的几种潜在关系，而猎物的丰度可能与go虾的状况有关。