SAâs shark and ray list promotes biodiversityReece Reid
South Africaâs first ever dedicated checklist of sharks, rays, skates, and ghost sharks has finally been published
SOUTH Africaâs first ever dedicated checklist of sharks, rays, skates, and ghost sharks has finally been published.
David Ebert (AKA âThe Lost Shark Guyâ), a research associate at the South African Institute for Aquatic Biodiversity (SAIAB), published the checklist after undertaking the South African Shark and Ray Protection Project.
Supported by SAIAB, the project was implemented by WILDOCEANS (a programme of the WILDTRUST), and funded by the Shark Conservation Fund.
Zululand is a renowned shark territory, but this time itâs not about rugby! The list, entitled An annotated checklist of the chondrichthyans of South Africa, includes sharks found in and around local waters, as well as their IUCN Red List status that outlines their risk of extinction.
First SA shark checklist goes live
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Credit: Georgia Aquarium
Shark scientists at Georgia Aquarium, Scripps Institution of Oceanography at UC San Diego, and Dalhousie University are challenging the status quo in shark and ray mating research in a new study that looks at biological drivers of multiple paternity in these animals. The results were published March 4 in the journal
Molecular Ecology.
Many species of sharks and rays exhibit multiple paternity, where females give birth to a litter of pups that have different fathers. While widely documented in scientific literature, the drivers of this phenomenon are not well understood. However, previous research has cited male aggression as the reason, claiming that the females are unable to avoid or submit to their advances during mating. This has led to the convenience polyandry theory, the assumption that there is a greater cost for females when refusing male mating attempts, as being the most widely credited explanation.
Lemon sharks on patrol slightly below the surface at dusk in the Bahamas at a shark sanctuary. Courtesy David Doubilet/Undersea Images
A jaw-dropping report last month in the Journal Nature reported that many species of sharks are at the point of no return.
âWe find that, since 1970, the global abundance of oceanic sharks and rays has declined by 71% owing to an 18-fold increase in relative fishing pressure,â the report reads. âThis depletion has increased the global extinction risk to the point at which three-quarters of the species comprising this functionally important assemblage are threatened with extinction.â
For decades, Clayton residents David Doubilet and Jennifer S. Hayes have come face-to-face with sharks all over the world and they have shared shark tales and other stories of their underwater dives and their encounters with various wildlife for National Geographicâs âLiveâ series all over the world, including two at the Clayton Opera
Shark, ray populations have declined by alarming 70 per cent since 1970s, study finds
WedWednesday 27
Sharks swim in formation among schools of fish off Murray Island in the Torres Strait.
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Shark and ray populations have declined by around 70 per cent since the 1970s, according to research published today in Nature.
Key points:
Oceanic shark and ray populations have declined around 70 per cent since the 1970s, the study in Nature found
Researchers attribute the decline to overfishing
Scientists say more strict management measures are needed to bring populations back to viable levels
A team of researchers from countries including the UK, Canada, and Australia looked at data from 18 shark and ray species, measuring their abundance as well as where they sat on the list of threatened species.
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