Abstract The ontogenetic diet shift to piscivory can be energetically beneficial for fish growth and allows larger, more energetically profitable prey to be consumed. A shift to piscivory may be easier for longer individuals within a cohort due to larger gape size, and an early shift is likely advantageous, potentially leading to increased growth rates and survival. Such length-dependent ontogenetic diet shifts may explain the intracohort variability in length that is common for age-0 walleye (Sander vitreus). The objectives of this study were to describe seasonal intracohort variability in length, identify the timing of the shift to piscivory and determine if the onset of piscivory was length-dependent in age-0 walleye. Walleye initially fed on zooplankton, but shifted to piscivory during July of 2010 and June of 2011. The onset of piscivory in age-0 walleye was associated with length-dependent differences during both years, in which longer individuals within the cohort became piscivorous earlier than shorter individuals within the same cohort. Intracohort variability in length was detected and increased postontogenetic diet shift. Age-0 walleye that experience a growth advantage could benefit from increased survival and feeding opportunities.

中文翻译：

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0 岁的角膜白斑 Sander 玻璃体显示依赖于长度的饮食转变为食鱼

摘要 个体遗传饮食转向食鱼可以在能量上有益于鱼类的生长，并允许消耗更大、能量更高的猎物。由于较大的张口尺寸，队列中较长的个体可能更容易转向食鱼，并且早期转变可能是有利的，可能导致增长率和存活率增加。这种依赖于长度的个体遗传饮食变化可能解释了 0 岁角膜白斑（Sander vitreus）常见的组内长度变异。本研究的目的是描述长度的季节性组内变异，确定转向鱼食的时间，并确定鱼食的发作是否与 0 岁角膜白斑的长度有关。角膜白斑最初以浮游动物为食，但在 2010 年 7 月和 2011 年 6 月期间转向食鱼。0 岁的角膜白斑开始吃鱼与这两年的长度依赖性差异有关，其中队列中较长的个体比同一队列中较短的个体更早地变得食鱼。检测到队列内的长度变异性和增加的后遗传饮食转变。具有生长优势的 0 岁角膜白斑可以从增加的存活率和喂养机会中受益。