Survey of macro-invertebrate gleaning in the Banate Bay intertidal area, eastern Panay Island [Philippines]

The gleaning fishery on the intertidal areas of Banate Bay, eastern Panay was surveyed monthly from February 2002 to January 2003, to derive information on species composition, catch, catch rates, and annual value. Total biomass, gleaning and turnover rates were determined from a fishery-independent survey conducted in June 2005. Catches of the fishery consisted of a total of 17 species, comprised of mollusks, crustaceans and a brachispod. The bivalves Katelysia hiantina, Scapharca inaequivalvis, and Gafrarum tumidum were the top three species, together comprising 88.79 percent of the total catch. The total mean daily catch per gleaner for all species was equivalent to 73.75 g/m-2/gleaner-1. Catch rate and catch volume for the mollusks were highest between May-July and November-December, coinciding with the southwest and northeast monsoons, respectively. The large riverine inputs to the area, together with the mangrove-derived organic matter, periodically resuspended by the tidal fluctuations, are seen as responsible for increasing organic matter content of the substrates and abundance of the species. Total annual catch of the fishery is estimated to range from 20,988.7 to 43,527.62 kg, with a median value of 31,205.6 kg. This latter value divided by the estimated total biomass in the area of 2,441.03 kg gives a turnover rate of 12.8. The total annual catch for the entire fishery is equivalent to a total value of PhP 421T to 897T/yr-1. The latter correspond to an annual income of PhP14,043.90 to 29,904.67/gleaner-1/yr-1, small amounts which may be sustainable due to the high turnover rate of the system.