RECRUITMENT OF POSTLARVAE OF THE SHRIMP P ENAEUS-SUBTILIS (PEREZ FARFANTE, 1967) IN 2 ESTUARIES OF FRENCH-GUIANA

In order to improve our knowledge of the recruitment of Penaeus subtil is in an industrial fishery at sea, a study was done on the postlarval stages. Variations in postlarval abundance were studied by sampling p lankton during 3 annual cycles in the Cayenne River and for one year i n the Sinnamary River. In the Sinnamary River, a salt wedge phenomenon encouraged sampling near the bottom. The influence of different envir onmental factors such as salinity, transparency and tidal current on a bundance is analysed. During a tidal cycle, maximal postlarval abundan ce is observed close by the maximum flood current, a little before the high-tide hour. The annual cycle of abundance in the two estuaries sh ows a main peak in April-May and some smaller peaks in June, September and December. A good relationship is observed between this annual cyc le of postlarval abundance and the breeding cycle of adult females at sea. The delay of one month between the breeding of adults at sea and recruitment of postlarvae in the estuaries corroborates the data in li terature. Postlarval abundance is much greater in May than in Septembe r; this confirms the hypothesis of a greater fecundity of the adult fe male population breeding in the first part of the year. The influence of environmental factors such as rainfall on the survival of postlarva e is discussed. Some information on the abundance of Xiphopenaeus kroy eri (Heller, 1862) postlarvae is given.