Effects of Catch-and-Release on Feeding Responses and Aggressive Behavior in Nile Tilapia - Dataset

In the present paper, we assess whether fish feeding responses and aggressive behavior can be affected by a hook injury (C&R). We assessed this question using an aggressive cichlid fish species, the Nile tilapia (Oreochromis niloticus), which displays pronounced dominance hierarchies and is a territorialist species. Hierarchy and territorialism are dependent of aggressivity and the nutritional state of individuals and thus may be affected by C&R. We exposed fish to three treatments: control (no-handling), chase/capture (C&C) and catch/release (C&R). Fish had their feeding responses (latency to feed and time to eat all feed pellets) evaluated prior to and at 2, 24 and 48 h post-handling, and the aggressive behavior was evaluated prior to and at 2, 6, 24 and 48 h post-handling. The aggressive behavior (latency, number of bites and confront index) was evaluated through the mirror test. We observed that 2 h after the catch-and-release, fish took a longer time to eat all pellets. In general, control fish displayed a consistent increase in aggressive behavior over time, and this pattern was interrupted by C&C, and an even larger response was seen in fish exposed to C&R, which had a consistent reduction in the number of bites post-handling compared to other groups. Although fish showed a tendency to become less aggressive post-C&R handling, catch-and-release did not largely affect their feeding responses or aggressive behavior, demonstrating that Nile tilapia is resistant/resilient to physical handling such as C&C or C&R.

本研究旨在探究钓获放流（Catch-and-Release，简称C&R）操作引发的钩挂损伤是否会影响鱼类的摄食反应与攻击行为。本研究选用具有显著优势等级体系的领地性攻击性慈鲷物种——尼罗罗非鱼（Oreochromis niloticus）作为实验对象，优势等级与领地行为依赖于个体的攻击性与营养状态，因此可能受到C&R操作的影响。实验设置三组处理：对照组（无任何操作）、追逐/捕获组（Chase/Capture，简称C&C）以及钓获放流组（C&R）。分别在处理前以及处理后2、24、48小时评估鱼类的摄食反应（摄食潜伏期与摄食完所有饲料颗粒的总时长）；攻击行为则在处理前以及处理后2、6、24、48小时通过镜像实验（Mirror Test）进行评估，评估指标包括攻击潜伏期、咬击次数与对峙指数。实验结果显示，钓获放流处理后2小时，鱼类摄食完所有饲料颗粒的时长显著延长。整体而言，对照组鱼类的攻击行为随时间推移呈持续上升趋势；该变化模式在C&C组中被打破，而C&R组的响应更为显著：与其他两组相比，该组鱼类在处理后的咬击次数持续降低。尽管C&R处理后鱼类表现出攻击性减弱的趋势，但总体而言钓获放流操作并未对其摄食反应与攻击行为造成显著影响，这表明尼罗罗非鱼对C&C或C&R这类物理操作具有较强的耐受性与恢复能力。