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 t...
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| Format: | Article |
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PeerJ Inc.
2018-06-01
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| Online Access: | https://peerj.com/articles/4904.pdf |
| _version_ | 1797419934754537472 |
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| author | Joshua P. Copping Bryce D. Stewart Colin J. McClean James Hancock Richard Rees |
| author_facet | Joshua P. Copping Bryce D. Stewart Colin J. McClean James Hancock Richard Rees |
| author_sort | Joshua P. Copping |
| collection | DOAJ |
| 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. |
| first_indexed | 2024-03-09T06:55:23Z |
| format | Article |
| id | doaj.art-a397a5fce3fa40eb9f0c5123a8de3db1 |
| institution | Directory Open Access Journal |
| issn | 2167-8359 |
| language | English |
| last_indexed | 2024-03-09T06:55:23Z |
| publishDate | 2018-06-01 |
| publisher | PeerJ Inc. |
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| spelling | doaj.art-a397a5fce3fa40eb9f0c5123a8de3db12023-12-03T10:07:24ZengPeerJ Inc.PeerJ2167-83592018-06-016e490410.7717/peerj.4904Does bathymetry drive coastal whale shark (Rhincodon typus) aggregations?Joshua P. Copping0Bryce D. Stewart1Colin J. McClean2James Hancock3Richard Rees4School of Environment and Life Sciences, University of Salford, Manchester, United KingdomEnvironment Department, University of York, York, United KingdomEnvironment Department, University of York, York, United KingdomMaldives Whale Shark Research Programme, York, United KingdomMaldives Whale Shark Research Programme, York, United KingdomBackground 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.https://peerj.com/articles/4904.pdfWhale sharkMarine megafaunaConservationBathymetryDistribution model |
| spellingShingle | Joshua P. Copping Bryce D. Stewart Colin J. McClean James Hancock Richard Rees Does bathymetry drive coastal whale shark (Rhincodon typus) aggregations? PeerJ Whale shark Marine megafauna Conservation Bathymetry Distribution model |
| 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 | Whale shark Marine megafauna Conservation Bathymetry Distribution model |
| url | https://peerj.com/articles/4904.pdf |
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