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Title: | Does bathymetry drive coastal whale shark (rhincodon typus) aggregations? |
Authors: | Copping, Joshua P. Stewart, Bryce D. McClean, Colin J. Hancock, James Rees, Richard |
Keywords: | Aquaculture Fisheries and fish science Biodiversity Conservation biology Marine biology Spatial and geographic information science Whale shark Marine megafauna Conservation Bathymetry Distribution model Marine ecosystems South Ari Atoll Maldives |
Issue Date: | 8-Jun-2018 |
Publisher: | PeerJ |
Citation: | Copping, J. P., Stewart, B. D., McClean, C.J., Hancock, J., & Rees, R. (2018), Does bathymetry drive coastal whale shark (rhincodon typus) aggregations?. PeerJ |
Abstract: | 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. |
URI: | http://saruna.mnu.edu.mv/jspui/handle/123456789/5062 |
Appears in Collections: | ތިމާވެށި Environment A
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