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Coral reef rays and sharks among the most threatened species in the world, study says

According to researchers from Simon Fraser University, 59% of shark and ray species that live in coral reefs face a trifecta of extinction risks – overfishing, habitat loss and climate change.

(CN) — Of the 1,199 species of rays and sharks on the planet, Samantha Sherman of Simon Fraser University and her colleagues say that 134 are associated with coral reefs. In their study published Tuesday in Nature Communications, the researchers say that the coral reef rays and sharks face double the extinction risk as the rest of their kind.

Per the study, coral reefs face the most intense threats of any ecosystem due to climate change, poor water quality and coastal development, but although climate change presents a long-term threat to the coral reef animals’ survival, the study says that overfishing is an immediate risk.

Coral reef fisheries support the livelihoods and food security of over half a billion people, but the study says that it also eliminates larger-bodied fishes such as bull sharks and reef manta rays. Sherman states that the size of the larger-bodied fishes makes it difficult for their species to recover.

“These species, and others with similar characteristics, are large-bodied and mature at an older age,” wrote Sherman via email. “This means it takes longer for them to mature and reproduce, making them more likely to be fished before having the chance to reproduce.”

The study says that the resulting losses disrupt the coral reefs' ecosystems and food chains that lead to declines in functionally important herbivores, with Sherman pointing out that this issue is prevalent in nations with greater fishing pressure, weaker governance and a lack of alternative livelihoods.

“Many of the countries with greater fishing pressure have large coastal populations that rely on resources from the ocean for food and earning money to support their families,” wrote Sherman. “These tend to be developing countries with fewer resources to manage the large number of fishers, hence the higher extinction risk for species in these countries.”

However, the researchers have recommendations for conservation efforts.

According to the study, conversation strategies must account for the needs of locals as developed nations have access to alternative livelihoods and protein sources that many developing nations do not have access to. As such, the researchers recommend three tactics already in use with varying degrees and varying success.

The first is implementing conservation actions regarding capacity development, such as monitoring fisheries and developing what the study called “Sustainable Development Goals and Convention on Biological Diversity targets.” The second focuses on improving the “education and diversification of rural livelihoods in nations with overexploited reefs to reduce fishing pressure on threatened species,” per the study. For these first two recommendations, the researchers state that it will increase the resilience of the coral reefs by maintaining abundance, conserving biodiversity, and reducing human reliance on reefs through alternative livelihoods.

Third, the researchers note that for scenarios such as recent increases in shark meat and ray skin trade that involve a large suite of reef species, they recommend consulting databases such as Convention on International Trade in Endangered Species of Wild Fauna and Flora to better use trade controls.

As for the public, Sherman wrote that they could aid conservation by buying sustainably, preferably locally, caught seafood using ecoguides and by encouraging their government policy makers to “prioritize shark and ray conservation and adopt catch limits that prevent overfishing. Finally, vocal, sustained support for shark conservation from the public is not only truly meaningful; it’s essential for securing a brighter future for these remarkable animals.”

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