Data from: DNA metabarcoding for diet analysis and biodiversity: A case study using the endangered Australian sea lion (Neophoca cinerea)

The analysis of apex predator diet has the ability to deliver valuable insights into ecosystem health, and the potential impacts a predator might have on commercially relevant species. The Australian sea lion (Neophoca cinerea) is an endemic apex predator and one of the world's most endangered pinnipeds. Given that prey availability is vital to the survival of top predators, this study set out to understand what dietary information DNA metabarcoding could yield from 36 sea lion scats collected across 1,500 km of its distribution in southwest Western Australia. A combination of PCR assays were designed to target a variety of potential sea lion prey, including mammals, fish, crustaceans, cephalopods, and birds. Over 1.2 million metabarcodes identified six classes from three phyla, together representing over 80 taxa. The results confirm that the Australian sea lion is a wide-ranging opportunistic predator that consumes an array of mainly demersal fauna. Further, the important commercial species Sepioteuthis australis (southern calamari squid) and Panulirus cygnus (western rock lobster) were detected, but were present in <25% of samples. Some of the taxa identified, such as fish, sharks and rays, clarify previous knowledge of sea lion prey, and some, such as eel taxa and two gastropod species, represent new dietary insights. Even with modest sample sizes, a spatial analysis of taxa and operational taxonomic units found within the scat shows significant differences in diet between many of the sample locations and identifies the primary taxa that are driving this variance. This study provides new insights into the diet of this endangered predator and confirms the efficacy of DNA metabarcoding of scat as a noninvasive tool to more broadly define regional biodiversity.

顶级捕食者的食性分析，可为生态系统健康状况，以及捕食者对具有商业价值物种的潜在影响提供重要见解。澳大利亚海狮（Neophoca cinerea）是特有顶级捕食者，也是全球最濒危的鳍足类动物之一。鉴于猎物可获得性对顶级捕食者的生存至关重要，本研究旨在通过对西澳大利亚西南部其分布范围内1500公里海域采集的36份海狮粪便样本进行分析，探究DNA元条形码技术（DNA metabarcoding）所能获取的食性信息。研究设计了多重聚合酶链式反应（PCR）检测体系，以靶向覆盖海狮的各类潜在猎物类群，包括哺乳类、鱼类、甲壳类、头足类以及鸟类。本次分析共获得超120万条元条形码序列，可归类至3个门下的6个纲，总计涵盖80余个分类单元。研究结果证实，澳大利亚海狮是一种广域性机会主义捕食者，其主要以各类底栖动物为食。此外，研究还检测到具有重要商业价值的澳洲枪乌贼（Sepioteuthis australis，南方枪乌贼）和西澳岩龙虾（Panulirus cygnus），但二者在样本中的检出率均低于25%。部分已识别的分类单元（如鱼类、鲨类和鳐类）进一步明确了此前关于海狮猎物的认知，而另有类群（如鳗类及两种腹足类动物）则为海狮食性研究提供了新的认知。尽管样本量有限，对粪便样本内的分类单元及操作分类单元（operational taxonomic units，OTU）进行空间分析后发现，多数采样点间的海狮食性存在显著差异，并明确了导致该差异的核心分类单元。本研究为这一濒危捕食者的食性研究提供了新的见解，同时证实了粪便DNA元条形码技术作为一种非侵入性工具，可用于更全面地解析区域生物多样性。