Previous reports of drastic declines in the elusive angelshark in Wales, U.K., may be overestimated and may be partly explained by changes in fishing trends throughout the past decades, according to a recent study.
The angelshark (Squatina squatina), listed as critically endangered on the IUCN Red List in 2006, is a bottom-dwelling shark that can grow up to 2.4 meters (8 feet) long. It was once a common predator in the sandy habitats of the Northeast Atlantic Ocean, Mediterranean Sea and Black Sea. However, over the past 50 years, the shark is reported to have declined dramatically in Wales — by as much as 70% between 1970 and 2016 — as it would often be caught as bycatch in nets used on the seabed to catch shellfish and other bottom-dwelling animals.
Most data on the angelshark have come from chance encounters with it as bycatch, the authors write. But it is important to consider how socioeconomic fishing practices have evolved and influenced historical sightings and records of the angelshark, they add.
To address this, researchers from the Zoological Society of London (ZSL), Natural Resources Wales and Welsh fishing organizations interviewed 27 Welsh commercial, recreational and charter fishers who actively fished within the Welsh Zone between 1968 and 2019. All of them recalled catching angelsharks incidentally, sometimes while fishing for thornback rays (Raja clavata), before the year 2000. One fisher told the researchers that angelsharks were a “nuisance” since they didn’t have commercial value and would damage fishing gear.
However, over the past decades, the fishers described several changes in the way they fished that may have made them less likely to encounter angelsharks. For example, the fishers said thornback ray populations had declined in the period, leading to a shift toward other species and fishing gear—this may have decreased the likelihood of catching angelsharks. Some fishers mentioned policy changes that made it difficult for them to fish in certain areas, while some spoke of reduced profitability among commercial fisheries and increased operational costs leading them to fish less, all of which may have decreased angelshark sightings.
“Identifying how changes to fishing practices over the last 51 years have impacted our ability to monitor them indicates that there may be more angelsharks swimming off the Welsh coast than we previously thought — we’re just having a harder time spotting them,” Francesca Mason, study’s lead author and ZSL researcher, said in a statement.
Mason said the new study shows the importance of working with fishers and combining their knowledge with research and science for conservation. However, she added that with fewer angelsharks now being accidentally caught, it also means there’s need for newer ways to monitor the species. ZSL researchers have used environmental DNA (eDNA) — bits of genetic matter that animals leave behind in their environment — to confirm the presence of angelsharks in Cardigan and Carmarthen Bay.
Banner image of an angelshark by Michael Bommerer via Wikimedia Commons (CCBY4.0).
