Top predator reveals the stability of prey community in the western subarctic Pacific

• Published in: PloS one Vol. 15; no. 6; p. e0234905
• Main Authors: Lin, Dongming, Chen, Xinjun
• Format: Journal Article
• Language: English
• Published: San Francisco Public Library of Science 19.06.2020; Public Library of Science (PLoS)
• Subjects: Biological research; Biology and Life Sciences; Chlorophyll; Diet; Digestive glands; Dynamic stability; Dynamic tests; Dynamics; Earth sciences; Ecology and Environmental Sciences; Ecosystems; Engineering research; Environmental aspects; Environmental changes; Fatty acids; Fisheries; Food chains; Isotopes; Laboratory animals; Marine ecosystems; Natural history; Neon; Niches; Oceans; Physical Sciences; Plankton; Predation (Biology); Predators; Prey; Sea surface temperature; Squid; Stable isotopes; Surface temperature; Pacific Ocean; China
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0234905

The stability of the ecosystems depends on the dynamics of the prey community, but changes in the composition and abundance of prey species are poorly understood, especially in open ocean ecosystems. We used neon flying squid Ommastrephes bartramii, an active top predator, as a biological sampler to investigate the dynamics of the prey community in the southwestern part of the Western Subarctic Gyre in the northwestern Pacific Ocean. Squid were collected monthly from July to November 2016. There were no significant differences among months in stable isotopes ([delta].sup.13 C and [delta].sup.15 N) in the digestive gland, a fast turnover organ reflecting recent dietary information. Similar findings were obtained from analyses of isotopic niche width and fatty acid profiles. The potential influence of the environment (monthly mean sea surface temperature, SST, and chlorophyll-a, Chl-a) on the prey community was examined with SST and Chl-a both varying significantly among sampling months. We found little evidence for significant effects of SST and Chl-a on the isotopic values, nor on the fatty acid profiles except for 20:4n6 and 24:1n9. These lines of evidence indicate that the prey community in the southwestern part of the gyre remains stable, with little evidence for systematic changes at the community level. This study provides a novel understanding of the dynamics of the prey community and highlights the use of top predators to study the trophic dynamics of an oceanic system where a long-term scientific survey is unavailable.