Quantifying the distribution and site fidelity of a rare, non-commercial elasmobranch using local ecological knowledge

Fishery catch records offer limited data to assess the status of rare, non-commercial species, including some sharks. Despite marine megafauna creating an important source of revenue though tourism, basic spatial information required to create conservation strategies is not available for many of these species. A cost-effective approach to assess the distribution of rare, non-commercial species is required to manage resources and inform conservation strategies in data-deficient areas. This study provides new information on the distribution and abundance of the zebra shark in southern Africa and examines if local ecological knowledge can be used to identify spatial and temporal trends of rare, non-commercial elasmobranchs. Trends identified from fisher interviews at two locations were compared to those collected using structured dive surveys. Both fisher interviews and structured surveys identified similar hotspot areas and temporal changes in the zebra shark population. Photographs of zebra sharks taken by researchers, dive operators, and recreational scuba divers between Pomene and Sodwana Bay were used to identify and provide information on the size, sex and movement of individuals. A combination of geo-located data gathered from one hundred interviews conducted with fishers at four different locations within Mozambique and sightings information from scuba divers were used in a species distribution model to determine the relative importance of environmental predictors and identify further areas of suitable habitat. Sea surface temperature was the most important factor in the coldest months, with distance from shore most limiting habitat suitability at other times of year. This approach could be applied in data-deficient regions to highlight areas of interest, prioritise research activities and inform conservation actions for rare, non-commercial marine megafauna.