Selectivity of experimental gillnets for fourwing flyingfish, Hirundichthys affinis, off Barbados

Four experimental gillnets of stretched mesh sizes 2.54, 3.18, 3.81 and 4.4 5 cm (1.00, 1.25, 1.50, 1.75 inches) were fished together to allow estimati on of gillnet selectivity for Hirundichthys affinis, by the method of compa ring the catches of fish in the various length classes in the different net s. Only the 3.18 cm and 3.81 cm nets caught appreciable numbers of fish. Th e combined selectivity of the 3.18 cm and 3.81 cm nets is close to unity fo r the range of sizes of H. affinis which are available to the nets. Therefo re, the size distribution of the combined catch for these nets can be used as an estimate of the size distribution of the available stock. The length frequency of fish caught in the 3.81 cm net coincided closely with the sele ctivity curve, indicating that this net effectively targets the sizes of fi sh available off Barbados. An increase or decrease in net mesh size by 0.64 cm (0.25") would be expected to result in a substantial reduction in catch per unit effort.