Étude de la biologie, de l’écologie et du profil biochimique des Scyliorhinus et des Galeus capturés sur les côtes de Mostaganem

Abstract

This work focuses on the biological and biochemical study of two shark species belonging to the families Scyliorhinidae and Galeidae: the small-spotted catshark (Scyliorhinus canicula) and the blackmouth catshark (Galeus melastomus), collected along the coast of Mostaganem between February and May 2026. A total of 60 specimens were sampled. The main objective was to analyze the biometric parameters, feeding habits, and biochemical composition of these two species. The biometric results showed that Scyliorhinus canicula exhibited larger body sizes than Galeus melastomus. Analysis of stomach contents indicated a carnivorous and benthophagous diet in both species, consisting mainly of crustaceans, fish, and mollusks. In Scyliorhinus canicula, the moisture content reached 67.4%, while the mineral matter content was 0.0766 g/g. In contrast, Galeus melastomus showed a moisture content of 67.6% and a mineral matter content of 0.0039 g/g. These results indicate a higher mineral composition in the first species. Quantitative analysis of total lipids using the Soxhlet method revealed lipid contents ranging from 7.80% to 14.80% in Scyliorhinus canicula, whereas Galeus melastomus showed values between 12.34% and 17.42%, highlighting biochemical differences between the two species. Protein contents determined by the Lowry method were relatively comparable between the two species, ranging from 7.95 to 11.20 g/100 g of muscle in S. canicula and from 7.26 to 9.26 g/100 g of muscle in G. melastomus.

Enzymatic hydrolysis using pepsin released 10.44 mg of peptides per gram of fresh flesh in the small-spotted catshark (Scyliorhinus canicula), compared with 8.22 mg/g obtained from the blackmouth catshark (Galeus melastomus).