Factors Influencing Dietary Changes of Walleye Pollock, <i>Gadus chalcogrammus</i>, Inhabiting the East Sea off the Korean Coast

This study examined the dietary patterns of walleye pollock, <i>Gadus chalcogrammus</i>, off the middle eastern coast of Korea between January 2016 and December 2017 to determine the influences of various predictors on dietary changes. Based on stomach content analyses, walleye pollock w...

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Autores principales:	Joo-Myun Park, Hae-Kun Jung, Chung-Il Lee
Formato:	article
Lenguaje:	EN
Publicado:	MDPI AG 2021
Materias:	stomach contents walleye pollock diet variations East Sea bottom gill net Naval architecture. Shipbuilding. Marine engineering VM1-989 Oceanography GC1-1581
Acceso en línea:	https://doaj.org/article/0ecce945964145d885ecb16c02eced44
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spelling	oai:doaj.org-article:0ecce945964145d885ecb16c02eced442021-11-25T18:03:40ZFactors Influencing Dietary Changes of Walleye Pollock, <i>Gadus chalcogrammus</i>, Inhabiting the East Sea off the Korean Coast10.3390/jmse91111542077-1312https://doaj.org/article/0ecce945964145d885ecb16c02eced442021-10-01T00:00:00Zhttps://www.mdpi.com/2077-1312/9/11/1154https://doaj.org/toc/2077-1312This study examined the dietary patterns of walleye pollock, <i>Gadus chalcogrammus</i>, off the middle eastern coast of Korea between January 2016 and December 2017 to determine the influences of various predictors on dietary changes. Based on stomach content analyses, walleye pollock was found to be a demersal carnivore that mainly consumes carid shrimps, euphausiids, mysids, teleosts, and cephalopods. The main prey species identified in the diets of walleye pollock were <i>Euphausia pacifica</i> (euphausiids), <i>Themisto japonicus</i> (amphipods), <i>Neomysis</i> spp. (mysids), <i>Neocrangon communis</i>, <i>Pandalus borealis</i> (carid shrimps), <i>Watasenia scintillans</i> (cephalopods), and <i>Bothrocara hollandi</i> (teleosts), which are hyper-benthic and bentho-pelagic organisms. Dietary analyses based on the weight contributions of different prey taxa to the diets revealed significant variations in dietary composition in terms of fish size, water depth, and season, implying intraspecific dietary segregation. Euphausiids dominate the diets of smaller individuals (<30 cm TL), whereas the contributions of carid shrimps, teleosts, and cephalopods increase as body size increases. Similarly, the latter three prey items are dominant food resources in deeper habitats. The PERMANOVA results revealed that the size-related spatial and temporal changes in dietary composition are all significant for the species, as well as their two- or three-way interactions among those factors, except for the size-depth interaction. The coupling effect of size and depth is indicative of depth-dependent differences in fish sizes, with the tendency for larger individuals to be distributed in deeper habitats. In addition, seasonal and interannual variations in water column structures are also evident in the diets, which may, in part, account for the diet seasonality observed in the stomach content analysis. The dietary analyses of walleye pollock will improve our understandings to seek functional role of the species in benthic food webs, and to predict the effects of environmental and anthropogenic perturbations.Joo-Myun ParkHae-Kun JungChung-Il LeeMDPI AGarticlestomach contentswalleye pollockdiet variationsEast Seabottom gill netNaval architecture. Shipbuilding. Marine engineeringVM1-989OceanographyGC1-1581ENJournal of Marine Science and Engineering, Vol 9, Iss 1154, p 1154 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	stomach contents walleye pollock diet variations East Sea bottom gill net Naval architecture. Shipbuilding. Marine engineering VM1-989 Oceanography GC1-1581
spellingShingle	stomach contents walleye pollock diet variations East Sea bottom gill net Naval architecture. Shipbuilding. Marine engineering VM1-989 Oceanography GC1-1581 Joo-Myun Park Hae-Kun Jung Chung-Il Lee Factors Influencing Dietary Changes of Walleye Pollock, <i>Gadus chalcogrammus</i>, Inhabiting the East Sea off the Korean Coast
description	This study examined the dietary patterns of walleye pollock, <i>Gadus chalcogrammus</i>, off the middle eastern coast of Korea between January 2016 and December 2017 to determine the influences of various predictors on dietary changes. Based on stomach content analyses, walleye pollock was found to be a demersal carnivore that mainly consumes carid shrimps, euphausiids, mysids, teleosts, and cephalopods. The main prey species identified in the diets of walleye pollock were <i>Euphausia pacifica</i> (euphausiids), <i>Themisto japonicus</i> (amphipods), <i>Neomysis</i> spp. (mysids), <i>Neocrangon communis</i>, <i>Pandalus borealis</i> (carid shrimps), <i>Watasenia scintillans</i> (cephalopods), and <i>Bothrocara hollandi</i> (teleosts), which are hyper-benthic and bentho-pelagic organisms. Dietary analyses based on the weight contributions of different prey taxa to the diets revealed significant variations in dietary composition in terms of fish size, water depth, and season, implying intraspecific dietary segregation. Euphausiids dominate the diets of smaller individuals (<30 cm TL), whereas the contributions of carid shrimps, teleosts, and cephalopods increase as body size increases. Similarly, the latter three prey items are dominant food resources in deeper habitats. The PERMANOVA results revealed that the size-related spatial and temporal changes in dietary composition are all significant for the species, as well as their two- or three-way interactions among those factors, except for the size-depth interaction. The coupling effect of size and depth is indicative of depth-dependent differences in fish sizes, with the tendency for larger individuals to be distributed in deeper habitats. In addition, seasonal and interannual variations in water column structures are also evident in the diets, which may, in part, account for the diet seasonality observed in the stomach content analysis. The dietary analyses of walleye pollock will improve our understandings to seek functional role of the species in benthic food webs, and to predict the effects of environmental and anthropogenic perturbations.
format	article
author	Joo-Myun Park Hae-Kun Jung Chung-Il Lee
author_facet	Joo-Myun Park Hae-Kun Jung Chung-Il Lee
author_sort	Joo-Myun Park
title	Factors Influencing Dietary Changes of Walleye Pollock, <i>Gadus chalcogrammus</i>, Inhabiting the East Sea off the Korean Coast
title_short	Factors Influencing Dietary Changes of Walleye Pollock, <i>Gadus chalcogrammus</i>, Inhabiting the East Sea off the Korean Coast
title_full	Factors Influencing Dietary Changes of Walleye Pollock, <i>Gadus chalcogrammus</i>, Inhabiting the East Sea off the Korean Coast
title_fullStr	Factors Influencing Dietary Changes of Walleye Pollock, <i>Gadus chalcogrammus</i>, Inhabiting the East Sea off the Korean Coast
title_full_unstemmed	Factors Influencing Dietary Changes of Walleye Pollock, <i>Gadus chalcogrammus</i>, Inhabiting the East Sea off the Korean Coast
title_sort	factors influencing dietary changes of walleye pollock, <i>gadus chalcogrammus</i>, inhabiting the east sea off the korean coast
publisher	MDPI AG
publishDate	2021
url	https://doaj.org/article/0ecce945964145d885ecb16c02eced44
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Factors Influencing Dietary Changes of Walleye Pollock, <i>Gadus chalcogrammus</i>, Inhabiting the East Sea off the Korean Coast

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