Mermaid’s purse
Eleonora has discovered underwater treasure in the Gulf of Naples: a special reef where secretive nursehound sharks lay hundreds of eggs! She and her colleagues keep an eye on the precious embryos with monthly dives to monitor them.
Eleonora de Sabata
Between us, Simona and I have studied and worked in, at and under the Mediterranean Sea for decades. Together we’ve snorkelled with pregnant sandbar sharks, tracked basking sharks at sea and in fish markets where they are sometimes illegally sold, trained coastguards to recognise protected species, and persuaded old fishermen to share their knowledge and anglers to release sharks alive. We’ve scanned the sea from aircraft looking for sharks and mobula rays and dived at night in sweeping currents to meet deep-water sixgills. We’ve also worked to reduce plastic litter in the sea. And all the time we’ve striven to...
Mermaid’s purse
The project will recruit recreational scuba divers to report sightings of the eggs, ‘mermaid’s purses’, of the nursehound shark Scyliorhinus stellaris. It aims to provide scientists with data on the presence and distribution of breeding grounds of this species and generate awareness about sharks within the diving community.
Presently there are no accurate data for the Mediterranean on the population size of this species, classified as Near Threatened on the IUCN Red List of Threatened Species. While little is known about the biology of the nursehound shark, it is a late-maturing species with low fecundity. The population may be fragmented, distributed inshore and offshore along the coast and islands.
The nursehound shark S. stellaris is a species of catshark found in the north-east Atlantic Ocean and Mediterranean Sea. It is generally found among rocks between 20 to 60 metres deep. It grows to 1.5 metres, has a broad, rounded head and its body is covered in black spots. It shares its range with the more common and much smaller, small-spotted catshark S. canicula. Nursehounds generally hide in small holes during the day and feed at night on a range of bony fishes, smaller sharks, crustaceans and cephalopods. Like other catsharks, the nursehound is oviparous: females deposit large (10 to 13 centimetre-long) eggcases and secure them with strong tendrils to seaweeds, seafans or sponges. These take up to nine months to hatch, with hatchlings measuring 10 to 16 centimetres at birth.
As demonstrated before in other public sighting-schemes, with clear and easy targets, divers can play an active part in monitoring the marine environment, providing at very low cost a considerable amount of data in a short time period. A specially formulated online questionnaire will be distributed to all diving centers around the Italian coasts. One or more ‘mermaid’s purse hunt’ events will be organised in the summer. The nursehound shark will be the tool to engage divers in conservation efforts and to introduce them to the plight of sharks in the Mediterranean Sea where, according to the IUCN, 42% of species are threatened. This SOSF grant will allow the creation of a dedicated website, Facebook page, information materials and activities during dive shows.
The main objectives of this project are to collect data on the presence and breeding areas of S. stellaris in Italian waters, and generate public awareness among the diving community about the presence of this and other species of sharks in the Mediterranean Sea, by:
- Collecting data on the presence, distribution and breeding areas of S. stellaris in Italian waters.
- Raising awareness among divers about this species in Italian waters
- Raising awareness among divers about the presence of and threats to sharks in the Mediterranean Sea.
- Reporting information on the presence and breeding areas of S. stellaris to the scientific community.