Recovered and released - A novel approach to oviparous shark conservation
Abstract The small spotted catshark Scyliorhinus canicula and the greater spotted catshark Scyliorhinus stellaris are benthic elasmobranchs frequently caught as bycatch in commercial fishing gears and landed at local fish markets for consumption. In recent years landings have begun to decline raising concerns for their population numbers and conservation status. In this study we present a novel, direct approach to shark conservation: removal of eggcases from dead Scyliorhinus specimens. Any viable embryos were observed during development and hatching. Post-hatching, pups were reared for 6 months and then released back into the wild. Eggcases were collected throughout the year, indicating the absence of a discreet breeding season in these species. Since January 2012, 689 eggcases were collected from females landed at the wholesale fish market in Malta, 548 S. canicula and 141 S. stellaris. From these a total of 186 shark pups were released back into the Maltese waters between January 2014 and March 2016. S. canicula carrying eggcases were found within a range of 36–52 cm total body length (TL), with most eggcases found in females of 41–47 cm TL. In S. stellaris eggcases were present in females ranging from 64 to 94 cm TL, with the majority of eggcases recovered from females of 77–88 cm TL. The recovery and release program is on-going with eggcase collection continuing for both species. This is to the best of our knowledge, the first report of the successful hatching and release of viable eggcases recovered from dead elasmobranchs. The program provides a practical methodology which can be optimised for other oviparous elasmobranch species landed by commercial fisheries globally; especially for unprotected species facing extensive local fishing pressure.