This project was designed with for objective on estimation of Biomass and optimum time for catch season of P.merguinsis and M.affinis shrimps. This investigation was carried out monthly by swept area method in coastal waters of Hormozgan province. The optimum time for fishing season in Bandar Abbas to Sirik waters in 2004,2005 and 2006 respectively was about 25/9/2004, 24/9/2005 and 25/9/2006. Total allowable catch (T.A.C.) for P.merguiensis and M.affinis estimated in 2004 to 2006 were 600, 170 tonnes, 850, 550 tonnes and 650, 400 tonnes respectively. The densest catch was obtained for P.merguiensis (from 58/5 to 65/5 %) and the least catch for P.indicus (from 0/04 to 1/1 % ), respectievly
