The Spatial Heterogeneity of the Black Scorpionfish, <i>Scorpaena porcus</i> (Scorpaenidae): Differences in Length, Dietary and Age Compositions

Abstract

The present study assessed spatial variations in several biological characteristics of Scorpaena porcus Linnaeus, 1758 and estimated length structure, dietary composition and growth parameters for the species. Sampling was carried out in two areas, about 200 km apart, in the coastal Adriatic Sea, which is the northernmost region of the Mediterranean. A total of 388 specimens of S. porcus were caught, 233 from the Split area and 155 from the Pag Island area, and a higher proportion of individuals in the ≤15 cm length classes were found in the Split area. The results of the age, growth and diet analyses demonstrated that the black scorpionfish is a slow-growing and long-lived species that feeds on a wide variety of plant and animal taxa and shows a high selectivity for crustacean decapods. Detailed comparisons and multivariate analyses showed significant fine-scale spatial structuring of the investigated species, as observed length, dietary and age compositions were heterogeneous among the two areas. Fish from the Pag Island area ingested a greater diversity of the prey types, fed to a greater extent on fishes, reached the highest total length and showed a higher growth rate. Such intraspecific variations could reflect adaptations to different environmental conditions and support the geographical scale at which local black scorpionfish populations should be managed.

Keywords

• growth rates
• diets
• location
• intraspecific variation
• multivariate analyses
• <i>Scorpaena porcus</i>