Abundance and seasonal distribution of Penaeus monodon postlarvae in the Sundarbans mangrove, Bangladesh

We record the decline of Penaeus monodon postlarvae (PL) in five rivers of the world's largest mangrove ecosystem, the Sundarbans, from 1992 to 1999. Shrimp aquaculture in the coastal belt of Bangladesh is dependent on the collection of P. monodon PL from the coastal rivers, and horizontal expansion of shrimp farming has resulted in a severe decline of this wild resource in the Sundarbans. Abundance of P. monodon PL was significantly (P<0.05) reduced in 1999 compared to the previous two-year studies (1992 and 1995) in the rivers. About 12–551 postlarvae of other shrimps, 5–152 finfish postlarvae and 26–1636 other macro-zooplankters are wasted during the collection of a single P. monodon PL. Water temperature and salinity of the river systems are correlated with P. monodon PL abundance. Besides P. monodon PL, inshore fishery of Hilsa ilisha, catfishes and Scylla serrata are also overexploited. The management practices and conservation of fishery resources of Sundarbans are reviewed in the context of its world heritage status.