For development purposes, some mangrove areas have been cut for aquaculture, housing, charcoal and other activities.  This project tries to relate the importance of mangroves to the prawn and finfish fisheries. The Sungai Merbok Mangrove Forest was selected as a study site and stake net or pukat cekam was used for fish sampling. This survey showed that Liza subviridis (Greenback mullet/belanak), Scatophagus argus (Spotted scat/ketang bunga), Siganus javus (Streaked spinefoot/dengkis), Pomadasys hasta (Lined silver grunter/gerut-gerut), Ambassis nalua (Glassfish/seriding putih), Arius sagor (Sagor catfish/pedukang), Pomadasys maculatum (Blotched grunter/gerut-gerut), Gerres abbreviatus (Deep-bodied majorra/kapas laut), Acentrogobius viridipunctatus (goby/belukor) and Liza oligolepis (Mullet/belanak) were dominant fish species in Sungai Dedap and Sungai Bujang. By using reference materials, the fish species caught were determined their feeding categories. This study shows that carnivores represented 47.4%, omnivores 21.6%, detrivores 20.6%, planktivores 10.4% and herbivores <0.1%. Funding for the project is from the Australian Centre for International Agricultural Research (ACIAR.FIS 92/18)  CSIRO Division of Marine Research.