Reproductive Biology of the Sulu Shrimp Metapenaeus suluensis Racek and Dall 1965 (Crustacea, Malacostraca: Penaeidae) in Iloilo River, West Central Philippines

The reproductive biology of the Sulu shrimp Metapenaeus suluensis Racek and Dall 1965 in Iloilo River, West Central Philippines was studied over a 1-year period from June 2013 to May 2014 by examination of monthly samples of 60 shrimp from catches of fish corral and motorised pushnet.The smallest sexually mature female was 92 mm total length and the smallest mature male was 81 mm. Ovarian histology showed four developmental stages namely immature, previtellogenic,vitellogenic and redeveloping. Testicular histology revealed five developmental stages namely immature, early maturing, mature, partially spawned and redeveloping. No spent males or females were observed during the study. Gonadosomatic indices of both sexes show major spawning from March to April, with a secondary season in September to October. The interruptions to the progression of monthly modal size frequency distributions, along with the absence of spent individuals suggest that mature individuals emigrate to spawn outside the river.