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Does bathymetry drive coastal whale shark (Rhincodon typus) aggregations?
BACKGROUND: The whale shark (Rhincodon typus) is known to aggregate in a number of coastal locations globally, however what causes these aggregations to form where they do is largely unknown. This study examines whether bathymetry is an important driver of coastal aggregation locations for R. typus...
Autores principales: | , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
PeerJ Inc.
2018
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5995094/ https://www.ncbi.nlm.nih.gov/pubmed/29900072 http://dx.doi.org/10.7717/peerj.4904 |
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author | Copping, Joshua P. Stewart, Bryce D. McClean, Colin J. Hancock, James Rees, Richard |
author_facet | Copping, Joshua P. Stewart, Bryce D. McClean, Colin J. Hancock, James Rees, Richard |
author_sort | Copping, Joshua P. |
collection | PubMed |
description | BACKGROUND: The whale shark (Rhincodon typus) is known to aggregate in a number of coastal locations globally, however what causes these aggregations to form where they do is largely unknown. This study examines whether bathymetry is an important driver of coastal aggregation locations for R. typus through bathymetry’s effect on primary productivity and prey availability. This is a global study taking into account all coastal areas within R. typus’ range. METHODS: R. typus aggregation locations were identified through an extensive literature review. Global bathymetric data were compared at R. typus aggregation locations and a large random selection of non-aggregation areas. Generalised linear models were used to assess which bathymetric characteristic had the biggest influence on aggregation presence. RESULTS: Aggregation sites were significantly shallower than non-aggregation sites and in closer proximity to deep water (the mesopelagic zone) by two orders of magnitude. Slope at aggregation sites was significantly steeper than non-aggregation sites. These three bathymetric variables were shown to have the biggest association with aggregation sites, with up to 88% of deviation explained by the GLMs. DISCUSSION: The three key bathymetric characteristics similar at the aggregation sites are known to induce upwelling events, increase primary productivity and consequently attract numerous other filter feeding species. The location of aggregation sites in these key areas can be attributed to this increased prey availability, thought to be the main reason R. typus aggregations occur, extensively outlined in the literature. The proximity of aggregations to shallow areas such as reefs could also be an important factor why whale sharks thermoregulate after deep dives to feed. These findings increase our understanding of whale shark behaviour and may help guide the identification and conservation of further aggregation sites. |
format | Online Article Text |
id | pubmed-5995094 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2018 |
publisher | PeerJ Inc. |
record_format | MEDLINE/PubMed |
spelling | pubmed-59950942018-06-13 Does bathymetry drive coastal whale shark (Rhincodon typus) aggregations? Copping, Joshua P. Stewart, Bryce D. McClean, Colin J. Hancock, James Rees, Richard PeerJ Aquaculture, Fisheries and Fish Science BACKGROUND: The whale shark (Rhincodon typus) is known to aggregate in a number of coastal locations globally, however what causes these aggregations to form where they do is largely unknown. This study examines whether bathymetry is an important driver of coastal aggregation locations for R. typus through bathymetry’s effect on primary productivity and prey availability. This is a global study taking into account all coastal areas within R. typus’ range. METHODS: R. typus aggregation locations were identified through an extensive literature review. Global bathymetric data were compared at R. typus aggregation locations and a large random selection of non-aggregation areas. Generalised linear models were used to assess which bathymetric characteristic had the biggest influence on aggregation presence. RESULTS: Aggregation sites were significantly shallower than non-aggregation sites and in closer proximity to deep water (the mesopelagic zone) by two orders of magnitude. Slope at aggregation sites was significantly steeper than non-aggregation sites. These three bathymetric variables were shown to have the biggest association with aggregation sites, with up to 88% of deviation explained by the GLMs. DISCUSSION: The three key bathymetric characteristics similar at the aggregation sites are known to induce upwelling events, increase primary productivity and consequently attract numerous other filter feeding species. The location of aggregation sites in these key areas can be attributed to this increased prey availability, thought to be the main reason R. typus aggregations occur, extensively outlined in the literature. The proximity of aggregations to shallow areas such as reefs could also be an important factor why whale sharks thermoregulate after deep dives to feed. These findings increase our understanding of whale shark behaviour and may help guide the identification and conservation of further aggregation sites. PeerJ Inc. 2018-06-08 /pmc/articles/PMC5995094/ /pubmed/29900072 http://dx.doi.org/10.7717/peerj.4904 Text en ©2018 Copping et al. http://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ) and either DOI or URL of the article must be cited. |
spellingShingle | Aquaculture, Fisheries and Fish Science Copping, Joshua P. Stewart, Bryce D. McClean, Colin J. Hancock, James Rees, Richard Does bathymetry drive coastal whale shark (Rhincodon typus) aggregations? |
title | Does bathymetry drive coastal whale shark (Rhincodon typus) aggregations? |
title_full | Does bathymetry drive coastal whale shark (Rhincodon typus) aggregations? |
title_fullStr | Does bathymetry drive coastal whale shark (Rhincodon typus) aggregations? |
title_full_unstemmed | Does bathymetry drive coastal whale shark (Rhincodon typus) aggregations? |
title_short | Does bathymetry drive coastal whale shark (Rhincodon typus) aggregations? |
title_sort | does bathymetry drive coastal whale shark (rhincodon typus) aggregations? |
topic | Aquaculture, Fisheries and Fish Science |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5995094/ https://www.ncbi.nlm.nih.gov/pubmed/29900072 http://dx.doi.org/10.7717/peerj.4904 |
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