The not so “Common Skate”: a charismatic species under threat
When the common skate, Dipturus batis, was named it was the most abundant skate in the northeast Atlantic and Mediterranean. Unfortunately, it no longer lives up to its name, as the IUCN Red List classifies its population as critically endangered and decreasing. The species is threatened throughout its range and locally extinct in the Baltic Sea and the majority of British coastal waters.
It is the largest skate in the world, at up to 2.85m long, and can live for 50-100 years, reaching maturity around 11 years of age. Large, long-lived, slow-growing species are often susceptible to extinction risk because of how slow they are to repopulate. However, conservation of the related flapper skate indicates that a quick recovery may be possible under sufficient protections.
The main threat to the common skate is fisheries. Historically it has both been directly targeted and badly impacted by bycatch. It is strictly protected throughout the EU, so it now illegal for commercial fishermen to actively target this species or keep them if accidentally landed.
Although often targeted by recreational fishers, these skates are returned to the water alive and evidence suggests there is a high likelihood of them surviving catch-and-release angling. However, as a benthic species living at a great range of depths from coastal waters to 600m, they are highly vulnerable to bycatch from large trawlers. Due to its large size it is vulnerable to fishing trawlers from a young age, reducing the likelihood of individuals reaching sexual maturity.
Trawl fisheries are highly damaging to almost all benthic species, causing massive problems with bycatch and decimating habitat by returning it to a very early successional state that can take years to recover from. As the common skate lives predominantly in cold waters, species in this habitat can take even longer to recover as they tend to be slower growing, such as hard corals and maerl beds. Trawling is particularly damaging in the deep-sea habitats that common skates populate, as these are not vulnerable to natural disturbance in the same way as shallow coastal habitats.
This therefore impacts not just the common skate but several of its prey species which include other skates, dogfish, catsharks, gurnards, flatfish, lobsters, and crabs. Due to the high profitability of this type of fishing, it is unlikely that it will be stopped any time soon without a great deal of political and public pressure.
The common skate is an example of how a large, charismatic species under legal protections in wealthy developed countries can still be critically endangered and in decline, and highlights the need for sustainable and highly regulated fisheries.
An article by Hayley McLennan
Cover Photo Copyright: Davy Holt