A critically endangered species of shark could be forced to adapt to new habitats – or face extinction – as a result of changes in the ocean predicted to occur as a result of climate change, a new study has suggested.
The whitefin swellshark (Cephaloscyllium albipinnum) is a species of catshark found in deeper waters just off Australia's south and east coasts. Its precise population numbers are uncertain, but the species has been assessed by the International Union for Conservation of Nature (IUCN) as Critically Endangered for a number of years due to declines largely attributed to fishing practices.
The new study, by researchers at the University of Plymouth, suggests that degrees of ocean change – including higher sea temperatures and shifts in ocean chemistry – predicted to occur by the end of this century could heighten its vulnerability.
Using a range of computer modelling, which accounted for the species' favoured habitats and forecast ocean conditions, researchers found that up to 70% of currently suitable habitats will be lost over the next 75 years. There is predicted to be an area within the Great Australian Bight that could offer whitefin swellshark populations refuge, with favourable ocean conditions and sources of the food they need to survive.
The only challenges with that, based on current knowledge of the species' whereabouts, are that the sharks – which grow to around 1.1-metres long – may need to move anywhere between 70km and 1100km in order to reach their potential new home. And it is likely they will not be the only species seeking refuge in the area, with a number of other marine species also likely to be forced to migrate polewards as they look to leave areas impacted by climate change.
Writing in the journal PeerJ, the researchers say the vulnerability of the species to the future effects of climate change is clear. However, they do believe there is cause for hope, with Australia being one of the world's more proactive nations when it comes to implementing conservation measures and management strategies, such as marine protected areas (MPAs).
The study was carried out by Kerry Brown, a BSc (Hons) Marine Biology and Oceanography graduate from the University of Plymouth, as part of her undergraduate dissertation. She said: "Most people will probably have never seen them, but whitefin swellsharks are an incredibly pretty species. However, despite them being listed as critically endangered, we actually know very little about their behaviour given its habitats are deep in the ocean. What we do know is that they have been on our planet for a very long time, so will have had to adapt to changes in their environment before. However, the threat to their future survival now is very real unless we take urgent steps to protect them."
Dr Robert Puschendorf, Associate Professor in Conservation Biology at the University of Plymouth, supervised the study and previously spent a decade working in Australia.
He added: "We have seen species move into different areas of the ocean in the past, so that offers some sense of hope for the whitefin swellshark. And the marine protected areas along the Australian coast are certainly a positive factor, although whether they are in the right place for this particular species is another matter. However, it does show the authorities in the region have the willingness and means to take action. The challenges faced by this – and other – species are now very different to what they may have encountered in the past, when you consider there are now very few parts of the planet that humans haven't damaged in some way. But our study shows we are potentially in a position where we can do something about it."
