Reef shark declines in remote atolls highlight the need for multi‐faceted conservation action

Graham, Nicholas A. J.; Spalding, Mark; Sheppard, Charles

doi:10.1002/aqc.1116

Cited by 139 publications

(137 citation statements)

References 37 publications

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“…Throughout their range, several reef-associated shark species have experienced large declines in abundances (Sandin et al 2008;Ward-Paige et al 2010;Graham et al 2010;Ruppert et al 2013). Therefore, knowledge of shark movements and habitat associations is critical for assessing risk of exposure to fishing, habitat loss and the effects of climate change.…”

Section: Discussionmentioning

confidence: 99%

Residency patterns and movements of grey reef sharks (Carcharhinus amblyrhynchos) in semi-isolated coral reef habitats

et al. 2014

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Section: Discussionmentioning

confidence: 99%

Residency patterns and movements of grey reef sharks (Carcharhinus amblyrhynchos) in semi-isolated coral reef habitats

et al. 2014

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“…Conservation strategies against this global destructive fishing pressure on sharks are heavily relying on methods and legislations to save these apex predators in every way possible. Already up to 90% of the global shark population has vanished and this is extremely dramatic (Graham et al, 2010). In the Mediterranean Sea, the situation is critical for large sharks, as shown by abundance and biomass calculations over time (Ferretti et al, 2008).…”

Section: Resultsmentioning

confidence: 99%

A non-invasive manual method for the assessment of pregnancy in female Scyliorhinus canicula catsharks

et al. 2018

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Enhanced survival of oviparous shark populations can rely on only one easily applicable method. We tested a powerful method to retrieve egg cases from dead oviparous females at the fish market which is non-invasive. We approved this method for Scyliorhinus canicula and Scyliorhinus stellaris (smallspotted catshark and Nursehound) in Valletta, Malta in 2014. Here, catsharks are landed in whole, whereas in many other Mediterranean countries sharks are already eviscerated when brought ashore. Saving egg cases bears the grateful opportunity to rescue shark embryos and this then helps again to restore fish stocks. The common work flow of fishermen is to throw away the egg cases when eviscerating the shark and so the embryos were left in the bin to die. To apply a non-invasive method is very important at fish markets where sharks are landed in one piece as fish brokers do not tolerate many dissections. So, our goal was to detect pregnant females with maximum accuracy and dissect only females with egg cases inside. Formerly, the common method used by members of Sharklab-Malta was to dissect females more or less randomly based on only two parameters (i) a total length above 40cm and (ii) a relatively corpulent body shape. This was not effective as many females were dissected without containing egg cases. This led to the more problematic fact that pregnant individuals were not found and so their offspring died in the end. The basic concept in our newly tested method is based on using a fixed touching pattern which allows to screen the belly of all females available simply by hand. To screen one female only 2 seconds are needed, and this works surprisingly well. We called this method "gotIt" simply because we got all available egg cases and could save all embryos. A validation underpinned the success and showed that gotIt works with 100% accuracy. After rescuing the egg cases they were transported to an aquarium. Egg cases were attached to a lanyard by their tendrils and left for development in the tank for 3-6 months (depending on their initial developmental stage at the fish market) at a water temperature of 15-19°C. After hatching, sharks were fed with squid and released into the sea. The number of rescued embryos arose significantly from five to above hundreds of shark pups which were saved and released by applying gotIt. Additionally, fishermen can be encouraged to use this method, as awareness programs can be promoted to encourage consumption of this sustainable fish, which can therefore increase the marketable prices. Widely applied, gotIt can help to preserve oviparous shark populations at fish markets where sharks are landed whole.

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“…Data on Indian Ocean shark populations are severely deficient by comparison, but available reports suggest declines in this region (e.g. in the Seychelles) may be similarly severe [25,26]. Shark fishing in the Seychelles has long been of strong socio-economic importance, but has intensified in recent years, following a temporary European Union (EU) ban on import of local swordfish Xiphias gladius, and persecution of sharks after two fatal shark attacks in 2011 [25,27].…”

Section: Introductionmentioning

confidence: 99%

Acoustic telemetry and network analysis reveal the space use of multiple reef predators and enhance marine protected area design

et al. 2016

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Marine protected areas (MPAs) are commonly employed to protect ecosystems from threats like overfishing. Ideally, MPA design should incorporate movement data from multiple target species to ensure sufficient habitat is protected. We used long-term acoustic telemetry and network analysis to determine the fine-scale space use of five shark and one turtle species at a remote atoll in the Seychelles, Indian Ocean, and evaluate the efficacy of a proposed MPA. Results revealed strong, species-specific habitat use in both sharks and turtles, with corresponding variation in MPA use. Defining the MPA's boundary from the edge of the reef flat at low tide instead of the beach at high tide (the current best in Seychelles) significantly increased the MPA's coverage of predator movements by an average of 34%. Informed by these results, the larger MPA was adopted by the Seychelles government, demonstrating how telemetry data can improve shark spatial conservation by affecting policy directly.

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Reef shark declines in remote atolls highlight the need for multi‐faceted conservation action

Cited by 139 publications

References 37 publications

Residency patterns and movements of grey reef sharks (Carcharhinus amblyrhynchos) in semi-isolated coral reef habitats

Residency patterns and movements of grey reef sharks (Carcharhinus amblyrhynchos) in semi-isolated coral reef habitats

A non-invasive manual method for the assessment of pregnancy in female Scyliorhinus canicula catsharks

Acoustic telemetry and network analysis reveal the space use of multiple reef predators and enhance marine protected area design

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