Identifying shark species responsible for fisheries depredation off Southeast Queensland, Australia

Vardon, Jaeden L.; Williams, Samuel M.; Bucher, Daniel J; Morgan, Jess A. T.

doi:10.1007/s11033-021-06460-4

Cited by 5 publications

(1 citation statement)

References 10 publications

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“…Sixty-six percent of the shark depredation events in this study were attributed to C. amblyrhynchos and eleven percent (or one incident) each to Bull Sharks, Great Hammerheads and Whitetip Reef Sharks. Vardon et al [ 57 ] identified shark species responsible for fisheries depredation off Southeast Queensland using mitochondrial DNA collected from swabs of depredated fish. All depredating shark species identified were in the genus Carcharhinus and greatest depredation was recorded by Bull Sharks ( n = 5).…”

Section: Discussionmentioning

confidence: 99%

Quantifying Catch Rates, Shark Abundance and Depredation Rate at a Spearfishing Competition on the Great Barrier Reef, Australia

Smith

Songcuan

Mitchell

et al. 2022

Biology

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We developed and applied a method to quantify spearfisher effort and catch, shark interactions and shark depredation in a boat-based recreational spearfishing competition in the Great Barrier Reef Marine Park in Queensland. Survey questions were designed to collect targeted quantitative data whilst minimising the survey burden of spearfishers. We provide the first known scientific study of shark depredation during a recreational spearfishing competition and the first scientific study of shark depredation in the Great Barrier Reef region. During the two-day spearfishing competition, nine vessels with a total of 33 spearfishers reported a catch of 144 fish for 115 h of effort (1.25 fish per hour). A subset of the catch comprised nine eligible species under competition rules, of which 47 pelagic fish were weighed. The largest fish captured was a 34.4 kg Sailfish (Istiophorus platypterus). The most common species captured and weighed was Spanish Mackerel (Scomberomorus commerson). The total weight of eligible fish was 332 kg and the average weight of each fish was 7.1 kg. During the two-day event, spearfishers functioned as citizen scientists and counted 358 sharks (115 h effort), averaging 3.11 sharks per hour. Grey Reef Sharks (Carcharhinus amblyrhynchos) comprised 64% of sightings. Nine speared fish were fully depredated by sharks as spearfishers attempted to retrieve their catch, which equates to a depredation rate of 5.9%. The depredated fish included four pelagic fish and five reef fish. The shark species responsible were Grey Reef Shark (C. amblyrhynchos) (66%), Bull Shark (Carcharhinus leucas) (11%), Whitetip Reef Shark (Triaenodon obesus) (11%) and Great Hammerhead (Sphyrna mokarran) (11%). There were spatial differences in fish catch, shark sightings and rates of depredation. We developed a report card that compared average catch of fish, sightings of sharks per hour and depredation rate by survey area, which assists recreational fishers and marine park managers to assess spatio-temporal changes. The participating spearfishers can be regarded as experienced (average 18 days a year for average 13.4 years). Sixty percent of interviewees perceived that shark numbers have increased in the past 10 years, 33% indicated no change and 7% indicated shark numbers had decreased. Total fuel use of all vessels was 2819 L and was equivalent to 6.48 tons of greenhouse gas emissions for the competition.

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Section: Discussionmentioning

confidence: 99%

Quantifying Catch Rates, Shark Abundance and Depredation Rate at a Spearfishing Competition on the Great Barrier Reef, Australia

Smith

Songcuan

Mitchell

et al. 2022

Biology

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Shark depredation: future directions in research and management

Mitchell

Drymon

Vardon

et al. 2022

Rev Fish Biol Fisheries

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Shark depredation is a complex social-ecological issue that affects a range of fisheries worldwide. Increasing concern about the impacts of shark depredation, and how it intersects with the broader context of fisheries management, has driven recent research in this area, especially in Australia and the United States. This review synthesises these recent advances and provides strategic guidance for researchers aiming to characterise the occurrence of depredation, identify the shark species responsible, and test deterrent and management approaches to reduce its impacts. Specifically, the review covers the application of social science approaches, as well as advances in video camera and genetic methods for identifying depredating species. The practicalities and considerations for testing magnetic, electrical, and acoustic deterrent devices are discussed in light of recent research. Key concepts for the management of shark depredation are reviewed, with recommendations made to guide future research and policy development. Specific management responses to address shark depredation are lacking, and this review emphasizes that a “silver bullet” approach for mitigating depredation does not yet exist. Rather, future efforts to manage shark depredation must rely on a diverse range of integrated approaches involving those in the fishery (fishers, scientists and fishery managers), social scientists, educators, and other stakeholders.

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Fishing behaviour and environmental variability influence depredation of pelagic longline catch by toothed whales

Monaghan,

Ravanello,

Ellis

et al. 2024

Fisheries Research

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Identifying shark species responsible for fisheries depredation off Southeast Queensland, Australia

Cited by 5 publications

References 10 publications

Quantifying Catch Rates, Shark Abundance and Depredation Rate at a Spearfishing Competition on the Great Barrier Reef, Australia

Quantifying Catch Rates, Shark Abundance and Depredation Rate at a Spearfishing Competition on the Great Barrier Reef, Australia

Shark depredation: future directions in research and management

Fishing behaviour and environmental variability influence depredation of pelagic longline catch by toothed whales

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