Two species of the shark-like rays known as wedgefish have been tagged by Marine Megafauna Foundation (MMF) scientists for a first-of-its-kind study in Mozambique.
The white-spotted guitarfish or bottlenose wedgefish (Rhynchobatus australiae) and the bowmouth guitarfish or shark ray (Rhina ancylostoma) are both IUCN-listed as Critically Endangered. They are particularly vulnerable because of their slow growth, late maturity and low reproduction rates.
The wedgefish are, like other rays, caught for their fins. However, so little is known about their biology or ecology that few management plans exist, says the MMF.
The Mozambique study is taking place in the protected Indian Ocean waters of the Bazaruto Archipelago National Park and Vilanculos Coastal Wildlife Sanctuary, with MMF working alongside park staff to identify primary aggregation sites.
The tags are a combination of acoustic transmitters, which send signals that can be picked up by listening stations for up to five years, and six-month pop-up archival satellite tags that record depth, temperature and light-level data. The two types provide the researchers with distinct but complementary information.
“We can learn where the animals spend most of their time, whether visits to specific sites are year-round or seasonal, how far they move, how deep they dive, and which temperatures they prefer,” said MMF co-founder and project co-lead Dr Andrea Marshall. “This will help to identify areas of critical habitat that must be prioritised for protection.