Department of Freshwater and Marine Ecology, IBED, University of Amsterdam, Amsterdam, the Netherlands.
Department of Coastal Systems, NIOZ Royal Netherlands Institute for Sea Research, Texel, the Netherlands.
Sci Adv. 2021 Mar 31;7(14). doi: 10.1126/sciadv.abf5908. Print 2021 Mar.
Fundamental insight on predator-prey dynamics in the deep sea is hampered by a lack of combined data on hunting behavior and prey spectra. Deep-sea niche segregation may evolve when predators target specific prey communities, but this hypothesis remains untested. We combined environmental DNA (eDNA) metabarcoding with biologging to assess cephalopod community composition in the deep-sea foraging habitat of two top predator cetaceans. Risso's dolphin and Cuvier's beaked whale selectively targeted distinct epi/meso- and bathypelagic foraging zones, holding eDNA of 39 cephalopod taxa, including 22 known prey. Contrary to expectation, extensive taxonomic overlap in prey spectra between foraging zones indicated that predator niche segregation was not driven by prey community composition alone. Instead, intraspecific prey spectrum differences may drive differentiation for hunting fewer, more calorific, mature cephalopods in deeper waters. The novel combination of methods presented here holds great promise to disclose elusive deep-sea predator-prey systems, aiding in their protection.
深海中捕食者-猎物动态的基本认识受到缺乏关于狩猎行为和猎物谱综合数据的阻碍。当捕食者针对特定的猎物群落时，深海生态位隔离可能会进化，但这一假设仍未得到验证。我们将环境 DNA (eDNA) 宏条形码与生物标记相结合，评估了两种顶级捕食性鲸类在深海觅食栖息地中的头足类群落组成。里索氏海豚和柯维氏喙鲸有选择性地针对不同的 epi/meso- 和 bathypelagic 觅食区，其中含有 39 种头足类动物的 eDNA，包括 22 种已知的猎物。出乎意料的是，觅食区之间猎物谱的广泛分类学重叠表明，捕食者的生态位隔离不仅仅是由猎物群落组成驱动的。相反，种内猎物谱差异可能导致在更深的水域中捕食数量更少、热量更高、更成熟的头足类动物的差异。这里提出的新方法组合具有揭示难以捉摸的深海捕食者-猎物系统的巨大潜力，有助于对其进行保护。
