Declining trends in annual catch rates of the tiger shark (Galeocerdo cuvier) in Queensland, Australia

Holmes, Bonnie J.; Sumpton, Wayne D.; Mayer, David G.; Tibbetts, Ian R.; Neil, D. T.; Bennett, Michael B.

doi:10.1016/j.fishres.2012.06.005

Cited by 47 publications

(66 citation statements)

References 38 publications

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“…Samples from the offshore gamefishing and commercial sectors provided similar numbers of male and female G. cuvier, while samples from shark control operations were biased toward female G. cuvier during this study period. Analysis of long-term QSCP catch data indicates that a sex ratio bias of 1.51:1 females to males exists in this program (Holmes et al, 2012). A higher abundance of female G. cuvier catch was also reported in coastal waters off Western Australia, which was hypothesized to occur due to a spatial segregation of juvenile male sharks (Heithaus, 2001).…”

Section: Discussionmentioning

confidence: 81%

“…The QSCP drumlines are highly selective for G. cuvier (91% of catch) while only 9% are caught in nets (Holmes et al, 2012). In the net-only NSWSMP the overall catch of these species is considerably less than in Queensland, with 49 G. cuvier and 110 C. carcharias caught between 1990…”

Section: Fishery Impacts : Shark Control Progra Msmentioning

confidence: 99%

“…The southwest Pacific population of G. cuvier sampled in the present study exhibited a slower rate of growth and slightly higher age at sexual maturity than reported elsewhere, indicating that recovery from depleted stocks may take longer in this region. This may explain why recent catch rate trends of G. cuvier in southeastern Australia have shown significant declines (Park, 2009;Reid et al, 2011;Holmes et al, 2012), when other regions are reporting increasing abundances (Dudley and Simpfendorfer, 2006). We must also consider that sample size, protocol methodology, verification and validation can also have considerable influence on regionally-specific growth model results (Cailliet and Goldman, 2004;Goldman, 2005).…”

Section: Validationmentioning

confidence: 99%

“…The tiger beaches (Fisheries, 2006;Reid et al, 2011;Holmes et al, 2012). Illegal foreign fishing activity in Australian Commonwealth waters also harvests an unquantifiable number of G. cuvier from Australian waters each year (Griffiths et al, 2008;Marshall, 2011).…”

Section: Introductionmentioning

confidence: 99%

“…Illegal foreign fishing activity in Australian Commonwealth waters also harvests an unquantifiable number of G. cuvier from Australian waters each year (Griffiths et al, 2008;Marshall, 2011). Recent research using data from game fishing activities and long term shark control programs has identified declining catch rates for G. cuvier on the east coast of Australia (Park, 2009;Reid et al, 2011;Holmes et al, 2012). To adequately understand the implications of these findings, examination of life history parameters is crucial to determine the extent the species' population would be affected by fishing and the ability to recover if stocks become depleted (Branstetter, 1990;Smith et al, 1998).…”

Section: Introductionmentioning

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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Section: Discussionmentioning

confidence: 81%

Section: Fishery Impacts : Shark Control Progra Msmentioning

confidence: 99%

Section: Validationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

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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Incidence of shark‐inflicted bite injuries on Australian snubfin (Orcaella heinsohni) and Australian humpback (Sousa sahulensis) dolphins in coastal waters off east Queensland, Australia

Nicholls

Peters

Cagnazzi

et al. 2023

Ecology and Evolution

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The ecology and evolution of prey populations are influenced by predation and predation risk. Our understanding of predator–prey relationships between sharks and dolphins is incomplete due to the difficulties in observing predatory events directly. Shark‐inflicted wounds are often seen on dolphin bodies, which can provide an indirect measure of predation pressure. We used photographs of Australian humpback and snubfin dolphins from north, central, and south Queensland to assess the incidence of shark‐inflicted bite injuries and to examine interspecific differences in bite injuries and their relationship with group sizes, habitat features, and geographical locations characteristic of where these individuals occurred. The incidence of shark‐inflicted scarring did not differ between species ( χ 2 = 0.133, df = 1, p = .715), with 33.3% of snubfin and 24.1% of humpback dolphins showing evidence of shark bites when data were pooled across all three study sites. Generalized additive models indicated that dolphins closer to the coast, with greater photographic coverage, and in north Queensland were more likely to have a shark‐inflicted bite injury. The similar incidence of shark‐inflicted wounds found on snubfin and humpback dolphins suggests both are subject to comparable predation pressure from sharks in the study region. Results highlight the importance that habitat features such as distance to the coast and geographical location could have in predation risk of dolphins from sharks, as well as the importance of considering photographic coverage when assessing the incidence of shark‐inflicted bites on dolphins or other marine animals. This study serves as a baseline for future studies on shark‐dolphin interactions in Queensland and into how predation may influence dolphin habitat usage, group living, and behavior.

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Intraspecific variation in vertical habitat use by tiger sharks (Galeocerdo cuvier) in the western North Atlantic

Vaudo

Wetherbee

Harvey

et al. 2014

Ecology and Evolution

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Tiger sharks (Galeocerdo cuvier) are a wide ranging, potentially keystone predator species that display a variety of horizontal movement patterns, making use of coastal and pelagic waters. Far less, however, is known about their vertical movements and use of the water column. We used pop-up satellite archival tags with two data sampling rates (high rate and standard rate tags) to investigate the vertical habitat use and diving behavior of tiger sharks tagged on the Puerto Rico–Virgin Islands platform and off Bermuda between 2008 and 2009. Useable data were received from nine of 14 sharks tagged, tracked over a total of 529 days. Sharks spent the majority of their time making yo-yo dives within the upper 50 m of the water column and considerable time within the upper 5 m of the water column. As a result, sharks typically occupied a narrow daily temperature range (∼2°C). Dives to greater than 200 m were common, and all sharks made dives to at least 250 m, with one shark reaching a depth of 828 m. Despite some similarities among individuals, a great deal of intraspecific variability in vertical habit use was observed. Four distinct depth distributions that were not related to tagging location, horizontal movements, sex, or size were detected. In addition, similar depth distributions did not necessitate similar dive patterns among sharks. Recognition of intraspecific variability in habitat use of top predators can be crucial for effective management of these species and for understanding their influence on ecosystem dynamics.

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Declining trends in annual catch rates of the tiger shark (Galeocerdo cuvier) in Queensland, Australia

Cited by 47 publications

References 38 publications

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

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

Incidence of shark‐inflicted bite injuries on Australian snubfin (Orcaella heinsohni) and Australian humpback (Sousa sahulensis) dolphins in coastal waters off east Queensland, Australia

Intraspecific variation in vertical habitat use by tiger sharks (Galeocerdo cuvier) in the western North Atlantic

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