Key predictors of extinction risk in sea breams and porgies (Family: Sparidae)

Identification, understanding and prediction of the factors that drive species to heightened risk of extinction are important goals for conservation, especially since few areas on the planet remain unaffected by human activities. Global extinction risk assessments of an entire family of ecologically complex marine fishes (family: Sparidae), using the International Union for Conservation of Nature Red List process, showed that 8.6% (13 species) of sparids are threatened. Intense fishing pressure and habitat destruction are the main reasons for the observed population declines. A further 7.9% (12 species) are classified as Near Threatened. The majority of the sparids (69.5%) are assessed as Least Concern, and these tended to have smaller body sizes, more widespread distributions, and shorter life spans. The remaining 21 species (13.9%) are listed as Data Deficient. In addition to presenting the first global assessment of sparid extinction risk, a Random Forest model identified correlates of extinction risk in the Sparidae using 33 biological and threat variables. The model correctly classified up to 90% of Red List category placements and showed complex interactions between intrinsic and extrinsic predictors. Larger body size was the most important predictor of extinction risk. Sparids with greater maximum sizes, ages, and turnover rates are at higher extinction risk. Conversely, lower area of occupancy and depth limit confer elevated risk. This analysis adds to the growing body of predictive extinction risk models in marine fishes and presents an opportunity to identify and mitigate threats affecting similar groups of highly-valued and ecologically important marine fishes.