Malawi Fisheries Research Institute, PO Box 27, Monkey Bay, MALAWI

Gear and Species Selectivity of the Gill net Fishery in Lake Malawi

Size selectivity of some important fish species caught in gill nets was estimated indirectly. Species composition of the catches from gill nets with mesh sizes between 1 and 2 inches showed that the catch was dominated by C. virginalis (74%) and that chambo contributed less than 0.2% to the catch of these small meshed gill nets. Chambo was not caught in these meshed because the size range of chambo that could be susceptible to this gear inhabits shallow waters where small meshed nets are not set. The small meshed gill nets were considered ideal for catching offshore cichlids. Gill nets with mesh sizes between 2 and 3 inches selected chambo at sizes corresponding with the size ranges at which this species migrates to deep water. Since this migration occurs before maturity, the use of gill nets with mesh size 2-3 inches is not recommended. Gill nets with mesh sizes between 3 and 4 inches were considered ideal since they select for mature chambo. However, the study showed that gill nets with the current mesh sizes in use do not catch mature catfish. For management purposes, development and adoption of distinct gill net fisheries for specific target species is suggested.