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 4.45 cm (1.00, 1.25, 1.50, 1.75 inches) were fished together to allow estimation of gillnet selectivity for Hirundichthys affinis, by the method of comparing the catches of fish in the various length classes in the different nets. Only the 3.18 cm and 3.81 cm nets caught appreciable numbers of fish. The combined selectivity of the 3.18 cm and 3.81 cm nets is close to unity for the range of sizes of H. affinis which are available to the nets. Therefore, 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 selectivity curve, indicating that this net effectively targets the sizes of fish 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.