BLUEFIN TUNA MATURITY IN TUNISIAN WATERS: A PRELIMINARY APPROACH

The aim of this paper is to increase our knowledge of the reproductive biology of the Mediterranean bluefin tuna. Particularly about sexual maturity, reproductive season and spawning area in Tunisian waters as an important tool for determining a correct policy for the management of fish stock. The histological analysis indicates that all the 3-age tunas were immature ones. The remaining bluefin females studied were mature independently of their age or FL. The activity stages found in the Tunisian tunas suggest us that these tunas are going to spawn in a short period, possibly in the central Mediterranean or Balearic island, along May and June. In conclusion, our data indicates that all 4-age Tunisian tunas are mature and are going to do effective spawning. At present, ICCAT use in the evaluation process the 5-age class like the first maturity one, if our data are confirmed by ulterior studies this age could change