Liversage Kiran, Nurkse Kristiina, Kotta Jonne, Järv Leili
Estonian Marine Institute, University of Tartu, Mäealuse 14, 12618, Tallinn, Estonia.
Estonian Marine Institute, University of Tartu, Mäealuse 14, 12618, Tallinn, Estonia.
Mar Environ Res. 2017 Dec;132:132-139. doi: 10.1016/j.marenvres.2017.10.017. Epub 2017 Nov 2.
Spatiotemporal environmental variation affects fish feeding behaviour and capacity for piscivorous control of prey populations, which is important for management when prey include invasive species causing ecosystem impacts. We assessed gut-contents of an important piscivore (European perch Perca fluviatilis) over two years, and analysed variables affecting initiation and amounts of feeding, focusing on an important invasive prey species, round goby (Neogobius melanostomus). We show that predation is primarily controlled by variation of physical and habitat characteristics surrounding perch. Fish prey began being incorporated in diets of perch that were >150 mm, with temperature conditions controlling initiation of their feeding. Total amounts of fish in perch diets, and amounts of round goby individually, were strongly affected by macrophyte cover; seldom were fish present in perch stomachs when macrophyte cover was >40%. Environmental densities of round goby were related to multivariate diet composition in ways that suggest predation of some native species may be relaxed in areas of dense round goby populations. There was evidence that perch predation is unlikely to limit populations of the invader, as there was only a weak relationship between round goby densities and amounts in gut contents. The results have ecosystem management implications, because some variables found to be important could be manipulated to control round goby or other similar invaders e.g. fisheries management of native piscivore stock-density and body-size, or modification of benthic environment structure.
时空环境变化会影响鱼类的摄食行为以及对猎物种群的食鱼性控制能力，当猎物包括造成生态系统影响的入侵物种时，这对于管理而言至关重要。我们在两年时间里评估了一种重要的食鱼动物（欧洲鲈Perca fluviatilis）的肠道内容物，并分析了影响摄食开始和摄食量的变量，重点关注一种重要的入侵猎物物种——圆口铜鱼（Neogobius melanostomus）。我们发现，捕食主要受鲈鱼周围物理和栖息地特征变化的控制。鱼类猎物开始被纳入体长超过150毫米的鲈鱼食谱中，温度条件控制着它们摄食的开始。鲈鱼食谱中鱼类的总量以及单独的圆口铜鱼数量，都受到大型植物覆盖度的强烈影响；当大型植物覆盖度超过40%时，鲈鱼胃中很少有鱼类。圆口铜鱼的环境密度与多变量饮食组成有关，这表明在圆口铜鱼密集的区域，对一些本地物种的捕食可能会减少。有证据表明，鲈鱼的捕食不太可能限制入侵者的种群数量，因为圆口铜鱼密度与肠道内容物数量之间的关系很弱。这些结果对生态系统管理具有启示意义，因为一些被发现重要的变量可以被操控来控制圆口铜鱼或其他类似的入侵者，例如对本地食鱼动物种群密度和体型的渔业管理，或者对底栖环境结构的改造。
