by CERF Hub scientist, Daniel Gledhill - CERF Biodiversity program 

A taxonomic error made in 1926 could contribute to one of the world’s largest skates being the first marine species fished to extinction. 

The European Common Skate (Dipturus batis), as the common name implies, was once one of the most abundant skates in the north-eastern Atlantic. It has become locally extinct over most of its previous geographic range due to pressure from commercial fishing. This has been exacerbated by its low fecundity, slow growth rate and late maturity. In 2000, the skate was listed as Endangered on the World Conservation Union’s Red List of Threatened Species. This status was upgraded to Critically Endangered in 2006.

The Common Skate has a confused taxonomic history, made worse by an influential 1920s publication which combined two recognised species under the name D. batis. Research published in Aquatic Conservation (November, 2009) led by Dr Samuel Iglésias refutes this, splitting the Common Skate once again into two nominal species: the Blue Skate (provisionally called D. cf. flossada) and the Flapper Skate (D. cf. intermedia). Eighty years of confusion, resulting in the confounding of catch data, has since masked the decline of both species. This is especially so for the more vulnerable of the two, the Flapper Skate which attains a larger size and matures at a later age, increasing the likelihood of capture before reaching sexual maturity. The study highlights the importance of accurate identifications in data collected for fisheries and conservation management.

Read Iglésias’ abstract:  http://onlinelibrary.wiley.com/doi/10.1002/aqc.1083/abstract
Samuel P. Iglésias, Lucile Toulhoat, Daniel Y. Sellos. (2009) Taxonomic confusion and market mislabelling of threatened skates: important consequences for their conservation status. Aquatic Conservation: Marine and Freshwater Ecosystems.