Geographical distribution and biomass estimation of the small pelagic species of the Tunisian waters during autumn season 2018.

Abstract

In Tunisia, the small pelagic species (Sardina pilchardus, Engraulis encrasicolus, Sardinella aurita, Boops boops, Trachurus sp and Scomber sp.) account for 40% of the total national landings. Thus, since 1996, INSTM has developed a multidisciplinary and long-term research program, dedicated to this group of fish, based on direct method. Thus, the INSTM organizes OASIS surveys (Operations Anchovy and Sardine of the Institute of Salammbô),) for stock assessment of small pelagic species by acoustic techniques based on échointégration and coupled to experimental fishing hauls. The last survey, OASIS_16, was carried out during autumn season of 2018. The biomasses estimated to 50 thousand tons are at their lowest levels since 1998. The largest decreases are observed in the Gulf of Gabes. However, specific and regional fluctuations are observed. Also, the most abundant species (Trachurus sp et  sardina pilchardus), have, in their majorities, sizes smaller than the size of first sexual maturity.