A recent SeaRover survey by Ireland’s Marine Institute’s remotely operated vehicle discovered a massive underwater nursery nearly 200 miles off the Irish coast. The findings, including rare underwater footage, were presented at the INFOMAR Seabed Mapping Seminar in Kinsale this week.
The Searover discovered large schools of school of black mouth catsharks and what is believed to be a “very large numbers of egg cases, commonly called mermaids purses, at depths reaching 750 meters while exploring Ireland’s deep-water coral reef systems. According to the researchers, such large concentrations of egg cases are rarely recorded and indicate females may gather in this particular area on the seafloor to lay their eggs.
“We are delighted to report the discovery of a rare shark nursery on a scale not previously documented in Irish waters,” expedition lead scientist David O’Sullivan said in a press release. “This discovery shows the significance of documenting sensitive marine habitats, and will give us a better understanding of the biology of these beautiful animals and their ecosystem function in Ireland’s Biologically Sensitive Area.”
The Searover also located another rare species of shark, the sail fin roughshark, during the expedition. The sailfin roughshark is listed as ‘Near Threatened’ by the International Union for Conservation of Nature meaning it may be considered threatened with extinction in the near future. The species grows up to a length of 1.2 m and is usually observed moving slowly with deep water currents feeding on small benthic invertebrates.
“Both species are of scientific interest as Ireland has an obligation to monitor deepwater sharks under the Marine Strategy Framework Directive,” Maurice Clarke from the Fisheries Ecosystem Advisory Services at the Marine Institute said.