dc.contributor.advisor |
Constantine, R |
en |
dc.contributor.advisor |
Erdmann, M |
en |
dc.contributor.advisor |
Francis, M |
en |
dc.contributor.author |
Meyers, Megan |
en |
dc.date.accessioned |
2017-05-08T02:32:51Z |
en |
dc.date.issued |
2017 |
en |
dc.identifier.uri |
http://hdl.handle.net/2292/32803 |
en |
dc.description |
Full text is available to authenticated members of The University of Auckland only. |
en |
dc.description.abstract |
The whale shark, Rhincodon typus, is often considered a cosmopolitan species found in tropical and subtropical oceans world-wide. Its surface swimming behaviour makes this filter-feeding fish ideal for photographic identification and satellite tagging. Approximately 13 whale shark aggregations have been documented world-wide, each of them with their own demography, residency patterns, and movement behaviours. This study is the first to identify the demography of the sharks found in Cenderawasih Bay, West Papua, Indonesia. Photographic surveys took place from 2010 to 2016, yielding 269 in-water whale shark sightings and 108 individuals identified in this area. This population is dominated by juvenile males (93% of all whale sharks) with a mean estimated total length of 4.9 ±0.1 m. We deployed 16 satellite tags from June 2015 to May 2016 to examine the long-term movement patterns of whale sharks in West Papua. Archived data from the Argos satellite system was received from 15 sharks over this period. Ten of these tags were recovered from the sharks after 88 to 499 days of deployment, facilitating fine-scale detailed analysis of these sharks’ vertical movements. Five sharks remained within the bay for the duration of the study. Sharks that left the bay were observed doing so at similar times of the year (late March to early May), but embarked on different paths in coastal or off-shore waters traveling up to 5,154 km away from the bay. Eleven out of fifteen sharks were present in the bay at the conclusion of our analysis, indicating high-site fidelity in this area. We hypothesize that horizontal movements may be in response to several environmental factors, including sea surface temperature and local current changes. A switching state space model showed that sharks in this area spent an average of 81% of their time foraging mostly in shallow waters, while the majority of traveling was observed in deeper waters. Sharks spent approximately 97% of their time in the epipelagic zone, with the majority of time (66%) spent in the first 25 m of the water column. Sharks exhibited mild reverse diurnal vertical movement with more time spent at the surface (<10 m) during the day than at night. However, 84% of deep diving activity (>200 m) occurred during the day. We suggest that vertical movements are a combination of response to available prey and thermoregulation. This study demonstrates complex and dynamic habitat utilization of whale sharks in a tropical embayment. The movement patterns of juvenile males show variable periods of residency in the bay, that are likely in response to different abiotic and biotic factors, which may trigger seasonal dispersal and affect diving behaviour. |
en |
dc.publisher |
ResearchSpace@Auckland |
en |
dc.relation.ispartof |
Masters Thesis - University of Auckland |
en |
dc.relation.isreferencedby |
UoA99264921810002091 |
en |
dc.rights |
Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated. Previously published items are made available in accordance with the copyright policy of the publisher. |
en |
dc.rights |
Restricted Item. Available to authenticated members of The University of Auckland. |
en |
dc.rights.uri |
https://researchspace.auckland.ac.nz/docs/uoa-docs/rights.htm |
en |
dc.rights.uri |
http://creativecommons.org/licenses/by-nc-sa/3.0/nz/ |
en |
dc.title |
Demography and movement ecology of whale sharks in Cenderawasih Bay, Indonesia |
en |
dc.type |
Thesis |
en |
thesis.degree.discipline |
Biological Science |
en |
thesis.degree.grantor |
The University of Auckland |
en |
thesis.degree.level |
Masters |
en |
dc.rights.holder |
Copyright: The author |
en |
pubs.elements-id |
624586 |
en |
pubs.record-created-at-source-date |
2017-05-08 |
en |
dc.identifier.wikidata |
Q112934444 |
|