The success of fish stocking programs is dependent on poststocking survival. However, survival can be influenced by size‐selective mortality, where larger individuals are expected to be less vulnerable to predation. Walleye Sander vitreus is a commonly stocked sport fish, but little is known regarding the role of size‐selective predation on age‐0 Walleye (90–290 mm TL) that are stocked in the presence of various piscivores with different foraging strategies and morphological features. Our objective was to evaluate whether the TL of consumed age‐0 Walleye was related to predator TL, predator gape height, or the probability of predation. We also assessed whether length distributions varied among stocked, recaptured, and consumed age‐0 Walleye. Data for the food habits of Largemouth Bass Micropterus salmoides, Smallmouth Bass M. dolomieu, Northern Pike Esox lucius, adult Walleye, and Muskellunge Esox masquinongy were collected from East Okoboji Lake and West Okoboji Lake, Iowa, USA during fall 2015–2017. Over the course of the study, 301 age‐0 Walleye were recovered from 3,514 predator stomachs. Mean, maximum (85th percentile), and minimum (15th percentile) TL of the consumed age‐0 Walleye were not related to the TL or gape height of the predators (P > 0.05), but the probability of predation decreased by 0.02 for every 10‐mm increase in the TL of the age‐0 Walleye. The length distributions indicated that consumed Walleye were generally smaller, whereas recaptured Walleye tended to be larger than stocked fish were. Our approach to evaluating poststocking size‐selective predation on age‐0 Walleye furthers the current understanding of the importance of size at stocking relative to stocking success and suggests that stocking Walleye > 220 mm is economically advantageous for reducing predation risk.

中文翻译：

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更大更好吗？评估年龄0角膜白斑的大小选择捕食

鱼类放养计划的成功取决于放养后的生存。但是，生存率会受到大小选择死亡率的影响，在这种情况下，较大的个体预计将更不容易受到掠夺。角膜白斑桑德vitreus是一种常用放养鱼类运动，但很少关于大小选择性捕食对在各种piscivores的存在下与不同的策略觅食和形态特征放养年龄0角膜白斑（90-290毫米TL）的作用是已知的。我们的目标是评估消耗的0岁角膜白垩病的TL是否与捕食者TL，捕食者间隙高度或捕食概率有关。我们还评估了长度分布是否在0岁至0岁的角膜白斑的放养，重新捕获和消费之间有所不同。大嘴鲈鱼的饮食习惯数据加州鲈，小嘴鲈鱼M.的Dolomieu，白斑狗鱼白斑狗鱼，成人角膜白斑和梭鱼白斑狗masquinongy秋季2015 - 2017年期间，从东欧克博奇湖和西欧克博奇湖，美国爱荷华州收集。在研究过程中，从3,514只捕食者的胃中回收了301只0岁的角膜白斑。所消耗的-0岁角膜白斑的平均，最大（第85个百分位数）和最小（第15个百分位数）TL与掠食者的TL或间隙高度无关（P  > 0.05），但0岁角膜白斑的TL的每增加10 mm，捕食的可能性降低0.02。长度分布表明，食用的角膜白斑通常较小，而重新捕获的角膜白斑往往比放养的鱼类更大。我们评估0岁龄Walleye的放养后尺寸选择性捕食的方法进一步加深了当前对放养大小相对于放养成功的重要性的认识，并建议放养220毫米以上的Walleye在降低捕食风险方面具有经济优势。