Cardiff School of Biosciences, Sir Martin Evans Building, Cardiff University, Museum Avenue, Cardiff, CF10 3AX, UK.
MARE-Marine and Environmental Sciences Centre, ISPA-Instituto Universitário, Rua Jardim do Tabaco 34, 1149-041, Lisboa, Portugal.
Sci Rep. 2017 May 3;7(1):1384. doi: 10.1038/s41598-017-01312-3.
The lunar cycle is believed to strongly influence the vertical distribution of many oceanic taxa, with implications for the foraging behaviour of nocturnal marine predators. Most studies to date testing lunar effects on foraging have focused on predator activity at-sea, with some birds and marine mammals demonstrating contrasting behavioural patterns, depending on the lunar-phase. However, to date no study has focused on how the lunar cycle might actually affect predator-prey interactions in the upper layers of the ocean. Here, we tested whether the diet of the predominantly nocturnal pelagic predator, the Bulwer's petrel (Bulweria bulwerii) would change throughout the lunar cycle, using molecular analysis to augment detection and taxonomic resolution of prey collected from stomach-contents. We found no evidence of dietary shifts in species composition or diversity, with Bulwer's petrel always consuming a wide range of mesopelagic species. Other co-variables potentially affecting light availability at-sea, such as percentage of cloud cover, did not confound our results. Moreover, many of the species found are thought not to reach the sea-surface. Our findings reveal that nocturnal predators are probably more specialized than previously assumed, irrespective of ambient-light, but also reveal deficiencies in our current understanding of species vertical distribution and predation-dynamics at-sea.
月球周期被认为强烈影响着许多海洋生物分类单元的垂直分布，对夜间海洋捕食者的觅食行为有影响。迄今为止，大多数测试月球对觅食影响的研究都集中在海上捕食者的活动上，一些鸟类和海洋哺乳动物表现出相反的行为模式，这取决于月相。然而，迄今为止，尚无研究关注月球周期如何实际影响海洋上层的捕食者-猎物相互作用。在这里，我们使用分子分析来增加从胃内容物中收集的猎物的检测和分类分辨率，测试了主要在夜间活动的远洋捕食者 Bulwer 海燕（Bulweria bulwerii）的饮食是否会在整个月球周期中发生变化。我们没有发现物种组成或多样性的饮食变化的证据，Bulwer 海燕总是消耗广泛的中层物种。其他可能影响海上光照的其他协变量，如云量百分比，并没有混淆我们的结果。此外，许多被发现的物种被认为不会到达海面。我们的研究结果表明，夜间捕食者可能比以前认为的更具专业化，而与环境光无关，但也揭示了我们目前对物种垂直分布和海上捕食动态的理解存在不足。
