Interactions between reproduction and fisheries in Bluefish, Pomatomus saltatrix (Pomatomidae), from Gulf of Gabes (Tunisia)
The bluefish, Pomatomus saltatrix (L., 1766), in the Gulf of Gabes (southeast of Tunisia) is a gonochoric species that reach first sexual maturity at the age of two years by a standard length (SL50) approaching 17.6 cm. Weekly changes in the Gonad-Somatic Index showed that spawning occurs in autumn (Oct-Nov). To get ready to reproduction, the bluefish saves some lipid reserves in muscles as well as in liver. Thus, the fishery season that spreads from 1st May to 31st August is well chosen because, on the one hand it corresponds to the period when the bluefish is in its best physiological state and on the other hand it is closed two months before the spawning. Furthermore, the minimal legal size of capture (22 cm SL) lets a safety margin of 4.4 cm allowing up to 50% of the population to reproduce at least once in their life. Therefore, the law in force always remains valid and deserves to be more reinforced.