Biogeographic patterns in the cartilaginous fauna (Pisces: Elasmobranchii and Holocephali) in the southeast Pacific Ocean
The abundance and species richness of the cartilaginous fish community of the continental shelf and slope off central Chile is described, based on fishery-independent trawl tows made in 2006 and 2007. A total of 194,705 specimens comprising 20 species (9 sharks, 10 skates, 1 chimaera) were caught at...
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| Format: | Article |
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PeerJ Inc.
2014-05-01
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| Online Access: | https://peerj.com/articles/416.pdf |
| _version_ | 1827606829298876416 |
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| author | Carlos Bustamante Carolina Vargas-Caro Michael B. Bennett |
| author_facet | Carlos Bustamante Carolina Vargas-Caro Michael B. Bennett |
| author_sort | Carlos Bustamante |
| collection | DOAJ |
| description | The abundance and species richness of the cartilaginous fish community of the continental shelf and slope off central Chile is described, based on fishery-independent trawl tows made in 2006 and 2007. A total of 194,705 specimens comprising 20 species (9 sharks, 10 skates, 1 chimaera) were caught at depths of 100–500 m along a 1,000 km transect between 29.5°S and 39°S. Sample site locations were grouped to represent eight geographical zones within this latitudinal range. Species richness fluctuated from 1 to 6 species per zone. There was no significant latitudinal trend for sharks, but skates showed an increased species richness with latitude. Standardised catch per unit effort (CPUE) increased with increasing depth for sharks, but not for skates, but the observed trend for increasing CPUE with latitude was not significant for either sharks or skates. A change in community composition occurred along the depth gradient with the skates, Psammobatis rudis, Zearaja chilensis and Dipturus trachyderma dominating communities between 100 and 300 m, but small-sized, deep-water dogfishes, such as Centroscyllium spp. dominated the catch between 300 and 500 m. Cluster and ordination analysis identified one widespread assemblage, grouping 58% of sites, and three shallow-water assemblages. Assemblages with low diversity (coldspots) coincided with highly productive fishing grounds for demersal crustaceans and bony fishes. The community distribution suggested that the differences between assemblages may be due to compensatory changes in mesopredator species abundance, as a consequence of continuous and unselective species removal. Distribution patterns and the quantitative assessment of sharks, skates and chimaeras presented here complement extant biogeographic knowledge and further the understanding of deep-water ecosystem dynamics in relation to fishing activity in the south-east Pacific Ocean. |
| first_indexed | 2024-03-09T06:44:56Z |
| format | Article |
| id | doaj.art-04dd564227b14d2789abbcfa416c4217 |
| institution | Directory Open Access Journal |
| issn | 2167-8359 |
| language | English |
| last_indexed | 2024-03-09T06:44:56Z |
| publishDate | 2014-05-01 |
| publisher | PeerJ Inc. |
| record_format | Article |
| series | PeerJ |
| spelling | doaj.art-04dd564227b14d2789abbcfa416c42172023-12-03T10:36:30ZengPeerJ Inc.PeerJ2167-83592014-05-012e41610.7717/peerj.416416Biogeographic patterns in the cartilaginous fauna (Pisces: Elasmobranchii and Holocephali) in the southeast Pacific OceanCarlos Bustamante0Carolina Vargas-Caro1Michael B. Bennett2School of Biomedical Sciences, The University of Queensland, St. Lucia, Queensland, AustraliaSchool of Biomedical Sciences, The University of Queensland, St. Lucia, Queensland, AustraliaSchool of Biomedical Sciences, The University of Queensland, St. Lucia, Queensland, AustraliaThe abundance and species richness of the cartilaginous fish community of the continental shelf and slope off central Chile is described, based on fishery-independent trawl tows made in 2006 and 2007. A total of 194,705 specimens comprising 20 species (9 sharks, 10 skates, 1 chimaera) were caught at depths of 100–500 m along a 1,000 km transect between 29.5°S and 39°S. Sample site locations were grouped to represent eight geographical zones within this latitudinal range. Species richness fluctuated from 1 to 6 species per zone. There was no significant latitudinal trend for sharks, but skates showed an increased species richness with latitude. Standardised catch per unit effort (CPUE) increased with increasing depth for sharks, but not for skates, but the observed trend for increasing CPUE with latitude was not significant for either sharks or skates. A change in community composition occurred along the depth gradient with the skates, Psammobatis rudis, Zearaja chilensis and Dipturus trachyderma dominating communities between 100 and 300 m, but small-sized, deep-water dogfishes, such as Centroscyllium spp. dominated the catch between 300 and 500 m. Cluster and ordination analysis identified one widespread assemblage, grouping 58% of sites, and three shallow-water assemblages. Assemblages with low diversity (coldspots) coincided with highly productive fishing grounds for demersal crustaceans and bony fishes. The community distribution suggested that the differences between assemblages may be due to compensatory changes in mesopredator species abundance, as a consequence of continuous and unselective species removal. Distribution patterns and the quantitative assessment of sharks, skates and chimaeras presented here complement extant biogeographic knowledge and further the understanding of deep-water ecosystem dynamics in relation to fishing activity in the south-east Pacific Ocean.https://peerj.com/articles/416.pdfSharkChimaeraSkateDiversityTrawlingCPUE |
| spellingShingle | Carlos Bustamante Carolina Vargas-Caro Michael B. Bennett Biogeographic patterns in the cartilaginous fauna (Pisces: Elasmobranchii and Holocephali) in the southeast Pacific Ocean PeerJ Shark Chimaera Skate Diversity Trawling CPUE |
| title | Biogeographic patterns in the cartilaginous fauna (Pisces: Elasmobranchii and Holocephali) in the southeast Pacific Ocean |
| title_full | Biogeographic patterns in the cartilaginous fauna (Pisces: Elasmobranchii and Holocephali) in the southeast Pacific Ocean |
| title_fullStr | Biogeographic patterns in the cartilaginous fauna (Pisces: Elasmobranchii and Holocephali) in the southeast Pacific Ocean |
| title_full_unstemmed | Biogeographic patterns in the cartilaginous fauna (Pisces: Elasmobranchii and Holocephali) in the southeast Pacific Ocean |
| title_short | Biogeographic patterns in the cartilaginous fauna (Pisces: Elasmobranchii and Holocephali) in the southeast Pacific Ocean |
| title_sort | biogeographic patterns in the cartilaginous fauna pisces elasmobranchii and holocephali in the southeast pacific ocean |
| topic | Shark Chimaera Skate Diversity Trawling CPUE |
| url | https://peerj.com/articles/416.pdf |
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