Population Viability Analysis of the Prionace glauca Stock in the South Atlantic

• Grant number: 24/18179-1
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: December 01, 2024
• End date: November 30, 2025
• Field of knowledge: Biological Sciences - Ecology - Applied Ecology
• Principal Investigator: Fabio Stucchi Vannucchi
• Grantee: Lucas Julio Agnello
• Host Institution: Instituto de Biociências (IB-CLP). Universidade Estadual Paulista (UNESP). Campus Experimental do Litoral Paulista. São Vicente , SP, Brazil

Abstract

Elasmobranchs, a subclass that includes the majority of Chondrichthyes, are distributed across all the world's oceans, playing important trophic roles in the ecosystems they inhabit, often as apex predators. However, their wide distribution contributes to increased fishing pressure on these species, especially sharks, which has led to the population decline of many of them. One such species is the blue shark (Prionace glauca), which is distributed in temperate and tropical waters. Although genetic studies indicate little differentiation within and between ocean basins, the population is generally divided into five fishery stocks: South Atlantic; North Atlantic; South Pacific; North Pacific; and Indian Ocean. In the South Atlantic, P. glauca is the most captured species by longline fishing, in addition to leading the international fin market - one of the main threats to shark populations today. The blue shark is currently classified as Near Threatened on the International Union for Conservation of Nature's (IUCN) Red List, due to recent studies indicating increasing population declines and illegal, unreported catches that interfere with the data. Population Viability Analysis (PVA) is a highly useful tool in such cases, as it consists of probabilistic studies that combine demographic and biological data to project the future of a population, taking into account anthropogenic and environmental threats, thus demonstrating its current level of vulnerability. This study aims to develop a population model for the South Atlantic stock of P. glauca through the use of the Vortex software, in order to carry out the species' PVA.