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ORIGINAL RESEARCH article

Front. Mar. Sci.
Sec. Marine Molecular Biology and Ecology
Volume 11 - 2024 | doi: 10.3389/fmars.2024.1411996

Metabarcoding and Morphological Analysis of Diets of Mesopelagic Fishes in the NW Atlantic Slope Water

Provisionally accepted
Ann Bucklin Ann Bucklin 1*Paola G. Batta Lona Paola G. Batta Lona 1Jennifer M. Questel Jennifer M. Questel 2Helena McMonagle Helena McMonagle 3Melissa Wojcicki Melissa Wojcicki 1Joel Llopiz Joel Llopiz 4Sarah Glancy Sarah Glancy 4Paul E. Caiger Paul E. Caiger 5Rene Francolini Rene Francolini 6Annette Govindarajan Annette Govindarajan 4Simon Thorrold Simon Thorrold 4Mike Jech Mike Jech 7Peter H. Wiebe Peter H. Wiebe 4
  • 1 University of Connecticut Avery Point, Groton, United States
  • 2 University of Alaska Fairbanks, Fairbanks, Alaska, United States
  • 3 School of Aquatic and Fishery Sciences, College of the Environment, University of Washington, Seattle, Washington, United States
  • 4 Woods Hole Oceanographic Institution, Woods Hole, Massachusetts, United States
  • 5 The University of Auckland, Auckland, Auckland, New Zealand
  • 6 Bigelow Laboratory For Ocean Sciences, Boothbay, Maine, United States
  • 7 Northeast Fisheries Science Center (NOAA), Woods Hole, Massachusetts, United States

The final, formatted version of the article will be published soon.

    The ocean twilight zone or mesopelagic (200-1000 m depth) is home to exceptional diversity and biomass of marine fish, which are key players in deep sea food webs. Despite their importance, many questions remain regarding trophic relationships and sources of productivity for mesopelagic fishes. We compare results of DNA metabarcoding and morphological taxonomic (microscopic) analysis of the gut contents of seven species of mesopelagic fishes collected from the NW Atlantic Ocean Slope Water during Summer 2018 and 2019. Metabarcoding used two gene regions: V9 hypervariable region of nuclear 18S rRNA and mitochondrial cytochrome oxidase I (COI). V9 sequences were classified into 14 invertebrate prey groups, excluding fish due to predator swamping. Ecological network analysis was used to evaluate relative strengths of predator-prey linkages. Multivariate statistical analysis revealed consistently distinct diets of four fish species in 2018 and/or 2019: Argyropelecus aculeatus, Chauliodus sloani, Hygophum hygomii, and Sigmops elongatus. Three other species analyzed (Malacosteus niger, Nemichthys scolopaceus, and Scopelogadus beanii) showed more variability between sampling years. COI sequences were classified into eight invertebrate prey groups, within which prey species were detected and identified. Considering all predator species together, a total of 77 prey species were detected with a minimum of 1,000 COI sequences, including 22 copepods, 18 euphausiids, and 7 amphipods. Morphological prey counts were classified into seven taxonomic groups, including a gelatinous group comprised of soft-bodied organisms. Integrative morphological-molecular analysis provided new insights into mesopelagic fish diets, including identification of key prey species, recognition of the importance of gelatinous prey, and characterization of differences in diet among fish predators in the NW Atlantic Slope Water.

    Keywords: mesopelagic, Fish diets, DNA metabarcoding, Morphological prey counts, food web

    Received: 03 Apr 2024; Accepted: 19 Sep 2024.

    Copyright: © 2024 Bucklin, Batta Lona, Questel, McMonagle, Wojcicki, Llopiz, Glancy, Caiger, Francolini, Govindarajan, Thorrold, Jech and Wiebe. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: Ann Bucklin, University of Connecticut Avery Point, Groton, United States

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