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

Abstract

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...

Genetic population structure and demography of an apex predator, the tiger shark Galeocerdo cuvier

“…For Scenarios 5 and 6, the end of the expansion/bottleneck was set at five generations in the past, which approximately corresponds to the ban on commercial exploitation of the tiger shark in Reunion Island (in 1999). Generation time was supposed to be around 7–10 years (Branstetter, Musick, & Colvocoresses, ; Holmes et al., ; Kneebone, Natanson, Andrews, & Howell, ; Wintner & Dudley, ).…”

PARAMETER PERTUMBUHAN HIU MACAN (Galeocerdo cuvier Peron & Lesuer, 1822) DI PERAIRAN SELATAN NUSA TENGGARA BARAT

“…(Tabel 1). Cailliet et al (1986) dan Goldman, (2005) dalam Holmes et al (2015), menyatakan bahwa pertumbuhan elasmobranch dipengaruhi oleh beberapa faktor lingkungan seperti m akanan, tem peratur dan cahaya. Selanjutnya Wirsing et al (2006) menyatakan bahwa perbedaan lingkungan dapat mempengaruhi kecepatan pertumbuhan.…”

Extracting DNA from ‘jaws’: high yield and quality from archived tiger shark (Galeocerdo cuvier) skeletal material

“…A Bioline ISOLATE II Genomic DNA kit was used for an initial evaluation of DNA concentration from different regions of the jaw. As shark vertebrae are used for museum display and age determination (see Holmes et al 2015), we drilled in a radial direction from the outer circumference towards the centre of each vertebra (see Fig. 1c) to minimize visual damage and allow for possible future use of the specimen in age determination.…”