Movements of whale sharks (<i>Rhincodon typus</i>) in South‐east Asian waters as determined by satellite telemetry

Eckert, Scott A.; Dolar, Louella; Kooyman, Gerald L.; Perrin, William F.; Rahman, Rozyanty

doi:10.1017/s0952836902000705

Cited by 62 publications

(73 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…data). In Indonesia, sharks are a major target of artisanal and commercial fisheries and it is likely that whale sharks are hunted in these waters as is the case in much of Southeast Asia (Eckert et al 2002). If over-fishing is occurring in part of the range of the Ningaloo sharks, the observation that many individuals return to this aggregation suggests that any demographic effects of this process will be seen in the protected population at Ningaloo.…”

Section: Discussionmentioning

confidence: 99%

“…If these estimates are correct, population reduction due to over fishing is likely and recovery will be slow. Additionally, recent studies have shown that the species is highly migratory, with some individuals travelling thousands of kilometres across oceans (Eckert et al 2002). The effects of over fishing in one part of the species range may thus be manifested in populations at other localities where the animals are protected from exploitation.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Population size and structure of whale sharks Rhincodon typus at Ningaloo Reef, Western Australia

Meekan¹,

Bradshaw²,

Press³

et al. 2006

Mar. Ecol. Prog. Ser.

163

222

View full text Add to dashboard Cite

We used photo-identification to produce estimates of population size and structure of whale sharks Rhincodon typus at Ningaloo Reef, Western Australia. We analysed photographs of whale sharks taken from 1992 to 2004. A combination of spot and stripe patterns behind the last gill slit and forward of the dorsal fin (lateral view), and distinctive scars and marks on the body and fins were useful for identifying individual sharks. These patterns appeared to be unique to individuals and distinctive markings could be recognized on some sharks for more than a decade. From 581 photographs, 159 individuals were identified. Of these, 74% were male, 16% were female and 10% were of indeterminate gender. Photographed sharks ranged in estimated size from 3 to 10 m total length (TL). The size distribution of sharks was bimodal with a large peak at 8 m and a smaller peak at 6 m TL. Sixty individuals were resighted during the study. Of these, 46 were resighted at different times during the same year (sometimes on multiple occasions) up to 4 mo after they were initially photographed, and 33 were resighted (4 on > 2 occasions) in different years. The interval between inter-annual resightings was typically 1 to 3 yr; however, 2 sharks were resighted after a period of 12 yr. We estimated the super population of whale sharks that visit Ningaloo Reef to consist of approximately 300 to 500 individuals (95% confidence interval) based on closed population models, or 320 to 440 based on Jolly-Seber open-population models. Our study shows that photo-identification offers a practical, non-invasive and non-destructive means to obtain data on the population size and demography of whale sharks.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Population size and structure of whale sharks Rhincodon typus at Ningaloo Reef, Western Australia

Meekan¹,

Bradshaw²,

Press³

et al. 2006

Mar. Ecol. Prog. Ser.

163

222

View full text Add to dashboard Cite

show abstract

“…Bruce et al 2006) to transoceanic (e.g. Eckert & Stewart 2001, Eckert et al 2002, Gore et al 2008) and trans-equatorial (e.g. Skomal et al 2009) crossings.…”

Section: Migrationsmentioning

confidence: 99%

Complexities of coastal shark movements and their implications for management

Speed

Field²,

Meekan

et al. 2010

Mar. Ecol. Prog. Ser.

268

239

View full text Add to dashboard Cite

Global declines of shark populations are of concern because of their largely assumed role as moderators of ecosystem function. Without long-term data on movement patterns for many species, it is impossible to infer relative extinction risk, which varies as a function of range, dispersal and habitat specificity and use. The past 50 yr of research on coastal sharks has revealed common movement patterns among species. In the horizontal plane, measured home range size generally increases with body size. We demonstrate meta-analytically the effects of increasing body size and monitoring time on home range size. Changes in the extent of horizontal movement might arise from ontogeny, predator avoidance or environmental tolerances. In the vertical plane, movement patterns include oscillatory vertical displacement, surface swimming, diel vertical migration and swimming at depth. These vertical movements are often attributed to foraging or navigation, but have been quantified less than horizontal patterns. Habitat specificity is often correlated with environmental conditions such as depth, salinity, substratum, and in some cases, prey availability. Site fidelity is common in species that use nursery areas. However, fidelity to mating, pupping, feeding and natal sites has only been observed in a few species. To date, few studies have examined habitat partitioning, although some general patterns have emerged: habitats appear to be subdivided by benthos type, prey availability and depth. The conservation of coastal sharks can be facilitated in some cases by the use of marine protected areas, especially for coastal resident species using specific nursery, reproduction or feeding areas. Partial protected-area closures might be effective during aggregation or migration periods to protect older size classes, but these must be applied with other management strategies such as reduced fishing and size or bag limits to protect individuals throughout different life history phases. More long-term research on habitat use, migration patterns and habitat partitioning is essential for developing successful management initiatives for coastal shark populations.

show abstract

“…Tracking studies and mtDNA data indicate, however, that whale sharks may be highly mobile between these visits (e.g. Eckert & Stewart 2001, Eckert et al 2002, Castro et al 2007, Hsu et al 2007, Rowat & Gore 2007, Brunnschweiler et al 2009), suggesting that multilateral regional cooperation and marine resource governance may be the key to conservation of whale sharks (Castro et al 2007).…”

Section: Introductionmentioning

confidence: 99%

Analysis of whale shark Rhincodon typus aggregations near South Ari Atoll, Maldives Archipelago

Riley¹,

Hale²,

Harman³

et al. 2010

Aquat. Biol.

View full text Add to dashboard Cite

We made surveys for whale sharks Rhincodon typus on a total of 99 d from April through June each year from 2006 to 2008 along the southern fringe of the South Ari Atoll, Maldives Archipelago. We recorded the length and sex of each shark observed and made photographs to facilitate repeated identification from their spot patterns using pattern-recognition software. We identified 64 whale sharks from digital photographs taken during 220 sightings over 3 yr. Approx. 87% of those sharks were immature males. The average length of recognisable sharks was 5.98 m (range 2.5 to 10.5 m), significantly shorter than that reported for whale sharks in other aggregations in the Indian Ocean. Our findings suggest that these sharks are either a small proportion of a local population or perhaps an even smaller component of a regional population in the western Indian Ocean. We applied a Lincoln-Petersen closed-population mark-recapture model and a Jolly-Seber openpopulation model to estimate population size, but found that neither model provided reliable results because key assumptions of each were not met.

show abstract

Movements of whale sharks (Rhincodon typus) in South‐east Asian waters as determined by satellite telemetry

Cited by 62 publications

References 6 publications

Population size and structure of whale sharks Rhincodon typus at Ningaloo Reef, Western Australia

Population size and structure of whale sharks Rhincodon typus at Ningaloo Reef, Western Australia

Complexities of coastal shark movements and their implications for management

Analysis of whale shark Rhincodon typus aggregations near South Ari Atoll, Maldives Archipelago

Contact Info

Product

Resources

About