An analysis of the data for the 12-year period 1967 to 1978, showed a gradual increase in the effort of trawlers from 1967, Metapenaeus monoceros forming about 12% of the prawn landings is an important component of the trawler catches. The fishery is generally better during January-May than in the other months. The landings of M. monoceros gradually increased from 20.3 t in 1967 to 485.61 in 1974 and then fluctuated thereafter. Catch per hour (CPH) varied between 1.0 kg in 1967 to 0.4 kg in 1978. The CPH more or less gradually declined from 1974 to 1978. The proportion of adults, particularly one-year olds, in the catches gradually declined during the 1974-1977 period. These two factors indicate that the stock is at the threshold level of optimum exploitation. A negative correlation between the CPH of M. monoceros in trawler catches of an year and the rainfall of the previous year is noticed. There appears to be a positive correlation between the CPH of M. monoceros in trawler catches of one-year and the C/E of M. monoceros in estuarine catches of the previous year. Based on the estuarine fishery it is possible to predict the abundance of M. monoceros in the inshore waters 5-6 months in advance of the main fishing season.