Ocean News

The skates formerly known as common

25th November 2009

It was recently revealed via genetic analyses that the already critically endangered common skate (Dipturus batis) in Europe is in fact two different species: the flapper and blue skate (D. intermedia and D. flossada). Consequently catches of the smaller, more resilient blue skate have in fact been masking the more rapid decline of the flapper skate, dramatically reducing the perceived population size. Dr Iglesias, who led the study, stated:

‘The threat of extinction for European Dipturus together with mislabelling in fishery statistics highlight the need for a huge reassessment of population for the different Dipturus species in European waters. Without revision and recognition of its distinct status the world’s largest skate, D. intermedia, could soon be rendered extinct.’

Similarly, genetic analysis of ragged-tooth sharks (Carcharias taurus) has found that the critically endangered population of Australia, although still the same species, may in fact be divided between eastern and western populations, essentially requiring that they are now managed as two separate populations: one does not have the ability to replenish the other.

Genetic tools can prove incredibly powerful, providing insights that direct observations and fisheries records can easily miss. Be sure to read more on how the SOSF shark DNA forensics project aims to characterise the global population structure of shark species and implement techniques to identify featureless fins from their ‘DNA barcode’, thereby aiding enforcement efforts to prevent trade in protected species.