The onset of piscivory in fish, resulting in a shift from zooplankton or invertebrate to fish prey, was studied on pikeperch (Sander lucioperca) using behavioural (attack, capture and swimming activity), morphological (allometry) and digestive enzymatic (trypsin, α-amylase and pepsin) analyses between larvae displaying or not piscivorous behaviour at different ages (23, 30, 37, 44 and 52 days post-hatching). The shift from zooplanktonic food items (Artemia nauplii) to a piscivorous diet did not occur at the same time for all individuals within the same cohort. Predation tests, conducted under controlled conditions (20°C; ad libitum feeding), showed that some larvae attacked fish prey as early as the age of three weeks (11.0 1.3 mm TL), while others did not start until the age of six weeks (16.6 1.9 mm TL). Piscivorous individuals were bigger, with larger heads, longer tails, higher acid protease and lower alkaline protease activities, than non-piscivorous conspecifics. In conclusion, high inter-individual variability in morphological and digestive system developments linked to predatory ability development could induce cannibalism in fish. This article is protected by copyright. All rights reserved.

中文翻译：

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淡水鱼类食鱼的发生：行为和生理特征分析

使用行为（攻击、捕获和游泳活动）、形态学（异速生长）和消化酶（胰蛋白酶、α-淀粉酶和胃蛋白酶）分析了不同年龄（孵化后 23、30、37、44 和 52 天）幼虫是否表现出食鱼行为。从浮游动物食物（卤虫无节幼体）到食鱼饮食的转变并非在同一队列中的所有个体同时发生。在受控条件（20°C；随意喂食）下进行的捕食测试表明，一些幼虫早在三周大（11.0 1.3 毫米 TL）时就开始攻击猎物，而其他幼虫直到六周大才开始攻击（16.6 1.9 毫米 TL）。食鱼的个体更大，与非鱼食性同种动物相比，头部更大，尾部更长，酸性蛋白酶更高，碱性蛋白酶活性更低。总之，与捕食能力发展相关的形态和消化系统发展的高度个体差异可能导致鱼类自相残杀。本文受版权保护。版权所有。