A0784
Title: Estimating rare species distribution with opportunistic data: The case of the white shark in the Mediterranean Sea
Authors: Greta Panunzi - Sapienza University of Rome & University of Salento (Italy) [presenting]
Abstract: Preserving apex predators in the ocean is extremely important. The lack of comprehensive abundance and distribution data often hinders our understanding of the population status of many endangered species. Occurrence records are usually limited and opportunistic, and fieldwork to gather more data is expensive and frequently not successful. Therefore, it is crucial to combine different sources of data to create models of species distribution that can help guide sampling and conservation efforts. The white shark is a rare but persistent inhabitant of the Mediterranean Sea, classified as critically endangered by the IUCN. Despite this, population abundance, distribution patterns, and habitat use remain poorly understood. Available occurrence records from 1985 to 2021 from diverse sources are utilized to construct a spatial log-Gaussian Cox process, incorporating data-source-specific detection functions and thinning and accounting for physical barriers. The model estimates white shark presence intensity and uncertainty using a Bayesian approach with integrated nested Laplace approximation (INLA). For the first time, species occurrence hotspots and landscapes of relative abundance (continuous measures of animal density in space) are projected throughout the Mediterranean Sea. This approach can be applied to other rare species for which presence-only data from different sources are available, enhancing conservation strategies.
