Temporal changes in the diet composition and trophic level of walleye pollock (Gadus chalcogrammus) inhabiting the middle-eastern coast of Korea.

Publisher: Elsevier Country of Publication: England NLM ID: 9882895 Publication Model: Print-Electronic Cited Medium: Internet ISSN: 1879-0291 (Electronic) Linking ISSN: 01411136 NLM ISO Abbreviation: Mar Environ Res Subsets: MEDLINE

Publication: Apr. <2000- >: Kidlington, Oxford : Elsevier
Original Publication: London : Applied Science Publishers, [c1978-

Food Chain* ; Diet*/veterinary ; Carbon Isotopes*/analysis ; Nitrogen Isotopes*/analysis; Animals ; Republic of Korea ; Ecosystem ; Gadiformes/metabolism ; Gastrointestinal Contents/chemistry ; Environmental Monitoring

The influences of oceanographic changes on diet composition and trophic level for pollock (Gadus chalcogrammus) inhabiting the East Sea off the Korean coast were examined based on stomach content and stable isotope analyses during 2016 and 2017. The diets of pollock consisted mainly of benthic crustaceans (particularly carid shrimps and euphausiids) and cephalopods, with a predominance of teleosts in the diets of larger individuals in deeper habitats. In 2016, amphipods, carid shrimps and cephalopods featured strongly in pollock diets, and the contribution of amphipods decreased in the diets of larger individuals and deeper depths. In 2017, euphausiids dominated at shallower depths, whereas the contributions of carid shrimps and teleosts increased in deeper habitats. Body-size-related differences in carbon stable isotope (δ ¹³ C) values were present in both 2016 and 2017, but size-related differences in nitrogen stable isotope (δ ¹⁵ N) values were only observed in 2017. The increased contribution of euphausiids during 2017 resulted in a distinct decrease in the trophic level of pollock compared to co-occurring higher trophic level predators, which can be linked to changes in habitat water temperature. Combined stomach contents and isotopic analyses provide a more comprehensive understanding of how fish diets and trophic levels fluctuate with changes in the type and abundance of prey resources in response to environmental changes.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2024 Elsevier Ltd. All rights reserved.)

Keywords: Depth layer; East sea; Stable isotope; Stomach contents; Trophic level; Walleye pollock

0 (Carbon Isotopes)
0 (Nitrogen Isotopes)

Date Created: 20240416 Date Completed: 20240609 Latest Revision: 20240609

20240610

10.1016/j.marenvres.2024.106493

38626629