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What makes Sanriku waters the southernmost habitat of northern fur seals? Winter–spring habitat use in relation to oceanographic environments

The waters off Sanriku (located on the northeastern coast of Honshu Island, Japan) provide the southernmost habitats of northern fur seals (Callorhinus ursinus) during winter and spring in the western North Pacific. The southward flowing cold Oyashio current and northward-flowing warm Kuroshio exten...

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Autores principales: Kanaji, Yu, Murase, Hiroto, Yonezaki, Shiroh
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10284389/
https://www.ncbi.nlm.nih.gov/pubmed/37343013
http://dx.doi.org/10.1371/journal.pone.0287010
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author Kanaji, Yu
Murase, Hiroto
Yonezaki, Shiroh
author_facet Kanaji, Yu
Murase, Hiroto
Yonezaki, Shiroh
author_sort Kanaji, Yu
collection PubMed
description The waters off Sanriku (located on the northeastern coast of Honshu Island, Japan) provide the southernmost habitats of northern fur seals (Callorhinus ursinus) during winter and spring in the western North Pacific. The southward flowing cold Oyashio current and northward-flowing warm Kuroshio extension mix there, making the area highly productive. Northern fur seals migrate into these waters from the breeding rookeries for feeding, and the locations of the southern margins of their habitats vary yearly. The key questions for understanding the seasonal migration patterns are “why” and “how” the species utilize these waters as the southernmost habitat. We estimated the density and abundance of northern fur seals using standard line-transect theory combined with habitat modeling. The spatial patterns of animal density were analyzed using generalized additive models with seven static and dynamic environmental covariates, and those covariates were selected based on Akaike’s information criterion (AIC). The lowest AIC model included depth, sea surface temperature, slope, and gradient in sea surface temperature. This model estimated well the spatial patterns of the density of the species, in which fur seals were widely distributed in the study areas, but less frequently encountered between the isobaths 100 m and 200 m. These spatially separated habitats suggest that the shelf break and offshore front play an important role in creating the feeding grounds of fur seals. On the other hand, sea surface temperature positively correlated with fur seals’ density up to 14°C. This may indicate that further warm waters work as a temperature barrier, and fur seals concentrate on the edge of suitable temperature ranges.
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spelling pubmed-102843892023-06-22 What makes Sanriku waters the southernmost habitat of northern fur seals? Winter–spring habitat use in relation to oceanographic environments Kanaji, Yu Murase, Hiroto Yonezaki, Shiroh PLoS One Research Article The waters off Sanriku (located on the northeastern coast of Honshu Island, Japan) provide the southernmost habitats of northern fur seals (Callorhinus ursinus) during winter and spring in the western North Pacific. The southward flowing cold Oyashio current and northward-flowing warm Kuroshio extension mix there, making the area highly productive. Northern fur seals migrate into these waters from the breeding rookeries for feeding, and the locations of the southern margins of their habitats vary yearly. The key questions for understanding the seasonal migration patterns are “why” and “how” the species utilize these waters as the southernmost habitat. We estimated the density and abundance of northern fur seals using standard line-transect theory combined with habitat modeling. The spatial patterns of animal density were analyzed using generalized additive models with seven static and dynamic environmental covariates, and those covariates were selected based on Akaike’s information criterion (AIC). The lowest AIC model included depth, sea surface temperature, slope, and gradient in sea surface temperature. This model estimated well the spatial patterns of the density of the species, in which fur seals were widely distributed in the study areas, but less frequently encountered between the isobaths 100 m and 200 m. These spatially separated habitats suggest that the shelf break and offshore front play an important role in creating the feeding grounds of fur seals. On the other hand, sea surface temperature positively correlated with fur seals’ density up to 14°C. This may indicate that further warm waters work as a temperature barrier, and fur seals concentrate on the edge of suitable temperature ranges. Public Library of Science 2023-06-21 /pmc/articles/PMC10284389/ /pubmed/37343013 http://dx.doi.org/10.1371/journal.pone.0287010 Text en © 2023 Kanaji et al https://creativecommons.org/licenses/by/4.0/This is an open access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
spellingShingle Research Article
Kanaji, Yu
Murase, Hiroto
Yonezaki, Shiroh
What makes Sanriku waters the southernmost habitat of northern fur seals? Winter–spring habitat use in relation to oceanographic environments
title What makes Sanriku waters the southernmost habitat of northern fur seals? Winter–spring habitat use in relation to oceanographic environments
title_full What makes Sanriku waters the southernmost habitat of northern fur seals? Winter–spring habitat use in relation to oceanographic environments
title_fullStr What makes Sanriku waters the southernmost habitat of northern fur seals? Winter–spring habitat use in relation to oceanographic environments
title_full_unstemmed What makes Sanriku waters the southernmost habitat of northern fur seals? Winter–spring habitat use in relation to oceanographic environments
title_short What makes Sanriku waters the southernmost habitat of northern fur seals? Winter–spring habitat use in relation to oceanographic environments
title_sort what makes sanriku waters the southernmost habitat of northern fur seals? winter–spring habitat use in relation to oceanographic environments
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10284389/
https://www.ncbi.nlm.nih.gov/pubmed/37343013
http://dx.doi.org/10.1371/journal.pone.0287010
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