A global extinction crisis is on the horizon for most coral reef sharks and rays thanks to current levels of overfishing and the background threat posed by climate change.
The startling findings were uncovered by a team of international researchers studying 134 Chondrichthyan species – the cartilaginous fishes – that either permanently reside in coral reefs or pass through from time to time.
Rays appear particularly at-risk, potentially because they both live within reef ecosystems and skirt their fringes, exposing them to fishing boats that trawl both regions.
Only one species – the bluespotted ribbontail ray – was found to be increasing in number.
Overall, 1 in 10 shark and ray species are likely to be critically endangered, with one-in-five endangered and around one-in-three vulnerable.
Overfishing – both directly and a result of by-catch – is the chief culprit pushing these species towards extinction.
And although there’s been a slowing in species decline since 2005 because of tighter fishing practices and protections, the loss of these animals continues.
“It would be great to see things turn around and start to climb [back up], but in the first instance, just arresting that decline would be a major piece of work,” says Colin Simpfendorfer, an adjunct professor at James Cook University who was one of the primary authors of the research.
While Simpfendorfer cites Australia as a better example of a nation managing its fisheries and protected areas along the continent’s northern coasts, it’s not a simple fix for others further north where most threatened species occur.
Coral reef ecosystems directly support the livelihoods and food security of 500 million people. If those people were a country, they would be the third biggest by population.
Local protections, improving the management of fisheries at a broad level and implementing protections would help , with the scientists warning the loss of biodiversity in reef ecosystems carries with it a risk of diminished economic returns and food security for communities.
Unfortunately, animals don’t recognise national boundaries, and the patchwork of management strategies and regulations currently in place pose major barriers to stemming species’ decline.
“In developing countries, the community reliance on fisheries that catch these species is very high and simply removing those will result in huge amounts of social and economic problems,” says Simpfendorfer.
“And so we need to work with those communities to work out how to best change their fishing practices to catch less sharks and rays, and set up protected areas that not only protect species but increase fisheries catches for the community.”
Similar research conducted in 2021 found at least 35% of all shark and ray species globally were threatened.