Cannibalism can be a significant factor limiting the survival of pike, Esox lucius, early life stages in both natural and aquaculture conditions. In the present research, type I cannibalism was studied in pike larvae (size range: 9–32.5 mm standard length, SL) in controlled conditions for 45 days post-hatching (dph). For this purpose, the occurrence of cannibalistic pairs, i.e. prey caught by a cannibal inside the cannibal’s mouth, was monitored for 15 min periods by two observers six times daily. Cannibalism was not observed in fish that still had yolk-sacs, but it did occur as soon as the yolk-sac was absorbed on 5 dph at a body size of 13 mm at 22 °C and 10 dph at a body size of 13.4 mm at 15 °C. The ratio of prey to predator size was on average 87%, but the smallest observed size difference was only 1.3%. The intensity of cannibalistic attacks depended on water temperature with more intense cannibalism at 22 °C than at 15 °C, and no cannibalism at 10 °C. Fluctuating asymmetry (FA) in all three sagittal otolith size parameters (area, width, and length) was higher in prey than in cannibals, the differences were not statistically significant.

中文翻译：

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正温度对梭鱼幼虫自相残杀行为的开始和强度的影响。自相残杀是否反映在耳石波动的不对称性中？

在自然和水产养殖条件下，同类相食可能是限制梭鱼、Esox lucius、早期生命阶段生存的重要因素。在目前的研究中，在受控条件下对梭鱼幼虫（尺寸范围：9-32.5 毫米标准长度，SL）在孵化后 45 天（dph）中研究了 I 型同类相食。为此，两名观察者每天六次监测食人对的发生，即食人者在食人者口中捕获的猎物，持续 15 分钟。在仍然有卵黄囊的鱼中没有观察到自相残杀，但是当卵黄囊在 22°C 下以 13 毫米的体型以 5 dph 吸收，在体长为 13.4 毫米时以 10 dph 吸收时确实发生了在 15°C。猎物与捕食者大小的比例平均为 87%，但观察到的最小大小差异仅为 1.3%。同类相食攻击的强度取决于水温，22 °C 时的同类相食比 15 °C 时更强烈，10 °C 时没有同类相食。猎物的所有三个矢状耳石尺寸参数（面积、宽度和长度）的波动不对称性 (FA) 均高于食人族，差异无统计学意义。