Reproductive biology and fecundity of the black scorpion fish Scorpaena porcus (Linnaeus, 1758) at the Algerian coast

This study provides elements on indices and the cycle of reproduction of the species Scorpaena porcus. The size of sampled specimens varied between 10.3 and 39.5 cm, with weight ranging between 25.1 and 656.7 g. The sex-ratio determined based on a sample of 343 individuals, was in favour of females (59.42%). The size at the beginning of the maturity was around 17.8 cm for females and 18.8 cm for males. The monthly evolution of the sexual maturity indicated that the spawning period occurs in summer, confirmed by the evolution of both the gonado-somatic index (GSI) and hepato- somatic index (HSI), as well as the oviparous reproduction mode of the species. The histological structure of the testicles was generally semi cystic. While the ovaries are characterized by the presence of stroma in the central cavity during the prematurity and gelatinous matrix at the maturity; the evolution of vitellogenesis started from the central cavity toward the peripheral cavity, surrounded by a thin membrane. The absolute fecundity of this species varied between 22600 and 93400 eggs, depending on the size, total weight and ovaries weight, whilst its relative fecundity varied from 97 to 258 eggs per gram of body mass for specimens weighting from 87.7 to 456 g. Females ranging from 18 to 24 cm in size, had a significant contribution in the reproduction of this species.