Quantifying the degree of protection afforded by a no-take marine reserve on an exploited shark

Silva, C da; Kerwath, Sven E.; Attwood, Colin G.; Thorstad, E. B.; Cowley, Paul D.; Økland, Finn; Wilke, CG; Næsje, Tor F.

doi:10.2989/1814232x.2013.769911

Cited by 41 publications

(43 citation statements)

References 59 publications

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“…Focusing research in these areas that can be considered as temporary, site specific or seasonal ranges is crucial to conservation management strategies (Hearn et al 2010, Heupel et al 2010, Revuelta et al 2012, Da Silva et al 2013. By using movement data, home range estimates (first described by Burt 1943 andMcNab 1963) have been used to define boundary lines for protected areas, reveal hotspots and areas of concern and inform policy makers on the effectiveness of management initiatives (Meyer & Holland 2005, Hearn et al 2010).…”

Section: Introductionmentioning

confidence: 99%

Core habitat use of an apex predator in a complex marine landscape

Jewell

Wcisel

Towner

et al. 2014

Mar. Ecol. Prog. Ser.

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Manual acoustic telemetry was used to describe core habitat use of white sharks in the complex marine landscape of the Dyer Island and Geyser Rock system near Gansbaai, South Africa. We compared home range estimates and swimming pattern analyses to those established at Mossel Bay, another white shark aggregation area roughly 300 km to the east. Traditional home range estimates used in Mossel Bay did not account for movement or barriers, and were thus biased towards areas with very little shark movement (i.e. potential resting areas). We found that adapting a Movement-based Kernel Density Estimate (MKDE) could account for movement and barriers, resolving these issues. At Dyer Island and Geyser Rock, daytime shark habitat use was adjacent to the seal colony, with low rates of movement, non-linear swimming patterns and small activity areas. At night, rates of movement and linearity increased as sharks travelled further from the islands into deeper waters. MKDEs revealed 4 focal areas of habitat use: a channel between the 2 islands, an area to the south of the seal colony, another area near a kelp feature to the southwest of the seal colony and a reef system to the northwest. These results differed significantly from the habitat use at Mossel Bay, where focal areas occurred adjacent to the seal colony during the hours of dawn and dusk. We discuss possible explanations for these differences. This study is the first to make use of MKDEs in a complex marine landscape and highlights important differences in habitat use of a threatened species between 2 separate aggregation areas.

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Section: Introductionmentioning

confidence: 99%

Core habitat use of an apex predator in a complex marine landscape

Jewell

Wcisel

Towner

et al. 2014

Mar. Ecol. Prog. Ser.

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“…However, the scale of commercial, artisanal and illegal fishing practices differs greatly among oceanic regions. More recently, the implementation of marine protected areas (MPAs) has been successful in reducing shark population declines in some areas (Dulvy et al 2006;Bond et al 2012;da Silva et al 2013), but these areas seldom encompass the full home range of larger shark species (Knip et al 2012). The southwest Pacific Ocean, comprising the east coast of Australia, New Zealand and many South Pacific Islands, encompasses a complex of exclusive economic zones (EEZ) and territorial sea and archipelago waters interspersed with international high seas.…”

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confidence: 99%

Tiger shark (Galeocerdo cuvier) movement patterns and habitat use determined by satellite tagging in eastern Australian waters

et al. 2014

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“…Although the implementation of marine protected areas (MPAs) has been successful in reducing shark population declines in some areas (Dulvy, 2006;Bond et al, 2012;da Silva et al, 2013), these areas seldom encompass the full home range of larger shark species (Knip et al, 2012). The western Pacific region comprises of the east coast of Australia, New…”

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confidence: 99%

“…This has resulted in an increased level of threat and often an incomplete understanding of population trends for these wide-ranging species. While the more recent implementation of Marine Protected Areas (MPAs) has been successful in reducing shark population declines in some areas Bond et al, 2012;da Silva et al, 2013), these areas seldom encompass the full home range of large migratory sharks (Knip et al, 2012). The southwest Pacific…”

mentioning

confidence: 99%

“…However, the scale of commercial, artisanal and illegal fishing practices differs greatly among oceanic regions. More recently, the implementation of marine protected areas (MPAs) has been successful in reducing shark population declines in some areas Bond et al 2012;da Silva et al 2013), but these areas seldom encompass the full home range of larger shark species (Knip et al 2012). The southwest Pacific Ocean, comprising the east coast of Australia, New Zealand and many South Pacific Islands, encompasses a complex of exclusive economic zones (EEZ) and territorial sea and archipelago waters interspersed with international high seas.…”

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confidence: 99%

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The biology and ecology of the tiger shark (Galeocerdo cuvier) on the east coast of Australia

Holmes¹

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The tiger shark (Galeocerdo cuvier) (Péron and Lesueur 1822) is the largest of the carcharhinids, with a circumglobal distribution in both tropical and warm temperate coastal and pelagic waters. In the western Pacific, G. cuvier movements are wide-ranging, encompassing the east coast of Australia and south Pacific Islands.Throughout the region, G. cuvier is exposed to a range of commercial, recreational, artisanal and illegal foreign fishery impacts, as both a target and by-product species.Listed as 'near threatened' on the International Union for Conservation of Nature (IUCN) Red List, suitable long term species-specific catch, catch rate and biological data are seldom available for large shark species like G. cuvier, particularly where historical commercial fishery logbook reporting has been poor.Shark control programs targeting large sharks along Australia's east coast have been in operation for over 60 years, using relatively standardised fishing gear in nearshore waters all year round, with historical catch and effort data recorded by shark contractors. Historical catch, catch rate and biological data collected through the Queensland Shark Control Program (QSCP) since 1993 were investigated, which revealed significant declines (p < 0.05) in catch rates of G. cuvier at some tropical and all sub-tropical locations along the Queensland coast. Significant temporal declines in the average size of G. cuvier also occurred at four of the nine locations analysed (p < 0.05), which could be indicative of fishing reducing abundance in these areas. Interannual variability in catches at each location was considerable and warranted careful interpretation with respect to estimating population abundance from these data.Investigation into the spatial and temporal movements of tiger sharks, and how their abundances fluctuate in relation to environmental influences, provided a basis for determining the factors driving this variability.Tiger shark movements were recorded using PAT Mk-10 and SPOT5 electronic tags to investigate G. cuvier spatial dynamics, site fidelity and habitat use off the east coast of Australia. Of the 18 tags deployed, 15 recorded information on depth and/or temperature, and horizontal movements, with tracking times ranging between four and 408 days. Horizontal movements were characterised by combinations of resident and transient behaviour that coincided with seasonal changes in water temperature, with summer migrations from sub-tropical Queensland waters to the southern temperate iii waters of New South Wales (NSW) to exploit the seasonally warm and prey abundant waters. While the majority of movement activity was focused around the continental slope, large-scale migration was evident with one individual moving from offshore Sydney, Australia, to New Caledonia (≈ 1800 km) in 48 days. Periods of tiger shark residency outside of Australia's fisheries management zones highlighted the potential vulnerability of the species to unregulated fisheries, and the importance of crossjurisdictional arrangemen...

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Quantifying the degree of protection afforded by a no-take marine reserve on an exploited shark

Cited by 41 publications

References 59 publications

Core habitat use of an apex predator in a complex marine landscape

Core habitat use of an apex predator in a complex marine landscape

Tiger shark (Galeocerdo cuvier) movement patterns and habitat use determined by satellite tagging in eastern Australian waters

The biology and ecology of the tiger shark (Galeocerdo cuvier) on the east coast of Australia

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