绿鳍马面鲀(Navodon septentrionalis)对4种大型水母的捕食行为

以绿鳍马面鲀为研究对象,通过室内受控实验,比较研究了其对我国沿海4种常见大型水母(海蜇、沙海蜇、海月水母和白色霞水母)的捕食差异。结果显示,体重为(215±20)g的绿鳍马面鲀对海月水母的捕食能力最强,日均最大摄食量为(150.7±18.6)g/fish,其次是海蜇和白色霞水母,日均摄食量分别为(129.7±11.6)和(120.0±19.3)g/fish,对沙海蜇的摄食量最少,为(92.5±11.3)g/fish;绿鳍马面鲀对海月水母与海蜇摄食量主要受投喂量影响,与规格无关,当投喂量小于其最大捕食量时,绿鳍马面鲀可捕食其周围所有水母,当投喂量超过其最大摄食量并继续增加时,绿鳍马面鲀摄食量保持不变,但残余水母的触手和伞部边缘均被啃食,继而导致水母摄食能力丧失,难以继续生存;在适口饵料冰鲜玉筋鱼充足的情况下,绿鳍马面鲀对水母具有明显的摄食偏向性,与仅投喂水母实验组相比,其对海月水母和海蜇的日均摄食量仅降低了20.2%和16.9%。研究结果表明,绿鳍马面鲀对上述4种水母皆能捕食。

Navodon septentrionalis Predation of Four Species of Giant Jellyfish

The predatory behavior of filefish Navodon septentrionalis to Aurelia aurita was observed before. Here we hypothesized that there were also predator-prey relationships between filefish and other jellyfish species. We explored the predatory behaviors of filefish to four species of giant jellyfish, including Rhopilema esculentum, Nemopilema nomurai, A. aurita and Cyanea nozakii, under laboratory conditions. We also studied the prey selection of filefish among jellyfish species of R. esculentum and A. aurita, and sand lance. Filefish weighted （215±20） g actively preyed on all four jellyfish species, and its daily medusae consumption of A. aurita, R. esculentum, C. nozakii, and N. nomurai was 150.7±18.6, 129.7±11.6, 120.0±19.3, and 92.5±11.3 g/fish respectively. It was the medusae biomass, not the bell diameter that affected the daily consumption when medusae of A. aurita and R. esculentum were fed to filefish. All medusae were preyed when their biomass was below the maximum consumption of filefish. Filefish did not prey more than the daily maximum consumption even if the medusa exceeded the maximum consumption, however, the remaining medusae all died because their tentacles and edges of umbrella were eaten. Filefish showed prey preference for jellyfish when sand lance was fed along with medusae of A. aurita and R. esculentum, and the daily consumption of A. aurita and R. esculentum was only reduced by 20.2% and 16.9%. These results should contribute to better understanding of the relationship between changes in fish population and giant jellyfish blooms in Chinese coastal areas.