Ontogenetic shift in foraging habit of ocean sunfish Mola mola from dietary and behavioral studies
Ontogenetic shift in foraging habit of ocean sunfish Mola mola from dietary and behavioral studies
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DOI：
10.1007/s00227-014-2416-8
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发表时间：
2014-06-01
期刊：
影响因子：
2.4
通讯作者：
Sato, Katsufumi
中科院分区：
文献类型：
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作者：
Nakamura, Itsumi;Sato, Katsufumi
海洋翻车鱼（Mola Mola）通常被认为以胶状浮游动物为食，但文献报道称，在它们的胃里发现了各种底栖生物。这可能反映了个体发生的饮食变化，因为对该物种的觅食习惯知之甚少。2009年至2010年，我们在日本岩手县（北纬39度22分，东经141A度58分）进行了一项行为研究，并结合饮食分析研究了它们的觅食习惯。我们的胃内容物分析（n = 17,31 -250 cm总长）表明，小翻车鱼（< 50 cm）以底栖甲壳类动物为食，而大翻车鱼（100 - 200 cm）以水母为食。体型较大的翻车鱼碳、氮稳定同位素比值较高。7月，在小型太阳鱼（49-58厘米，n = 5）身上部署加速度计和动物携带的相机，表明它们可能在靠近海床时进食。这表明小太阳鱼可能以底栖动物为食。7月份在大型翻车鱼（84-164 cm, n = 4）身上部署的加速磁强计证实了7月份的大型翻车鱼在水面和深水（bbb100 m）之间来回游动。在深水中观察到暂时的减速，这被认为与浮游生物猎物的进食有关。11月，在大型太阳鱼（105厘米，n = 3）身上部署的加速磁力计显示出几次爆发，它们在混合层（0-100米）内游动，这可能与追逐快速猎物有关。这些结果表明海洋翻车鱼有不同的饮食，这取决于它们的体型和可能的季节。
The ocean sunfish (Mola mola) is typically considered to feed on gelatinous zooplankton, but reports in the literature describe various benthic organisms being found in their stomachs. This might reflect ontogenetic dietary shift, as little was known about the foraging habit of this species. We examined their foraging habits using dietary analyses in combination with a behavioral study in Iwate, Japan (39A degrees 22'N, 141A degrees 58'E) from 2009 to 2010. Our stomach content analyses (n = 17, 31-250 cm total length) suggested that small sunfish (< 50 cm) feed on benthic crustaceans, but large sunfish (> 200 cm) feed on jellyfish. Larger sunfish showed higher values of both carbon and nitrogen stable isotope ratios. Deployment of accelerometers and animal-borne cameras on small sunfish in July (49-58 cm, n = 5) suggested their possibility of feeding, while they stayed near the seabed. This indicates that small sunfish might feed on benthic preys. Deployment of accelero-magnetometers on large sunfish in July (84-164 cm, n = 4) clarified that the large sunfish in July swam back and forth between the surface and deep water (> 100 m). Temporary decelerations, which were considered to be associated with feeding of planktonic prey, were observed in deep water. Whereas deployment of accelero-magnetometers on large sunfish in November (105 cm, n = 3) showed several bursts, they swam within the mixed layer (0-100 m), which might be associated with chasing of rapid prey. These results suggest that ocean sunfish have heterogeneous diets depending on their body size and possibly season.