EFFECT OF SNOOD LENGTH AND HANGING RATIO ON EFFICIENCY AND SELECTIVITY OF BOTTOM-SET GILLNETS FOR PIKEPERCH, STIZOSTEDION-LUCIOPERCA L, ANDBREAM, ABRAMIS-BRAMA

Experiments were conducted with multi- and monofilament bottom-set gil lnets of various mesh sizes (50, 55 and 65 mm bar mesh), snood length (0.6 and 1.1 m) and hanging ratio, E (0.25, 0.33, 0.5 ) to study the i nfluence of gear construction on the selectivity of the nets for catch ing pikeperch (Stizostedion lucioperca) and bream (Abramis brama). Cat ches were always higher in the conventional gillnets with 1. 1 m snood s, but on an exposed net area basis, catches of bream were higher in t he nets with 0.6 m snoods. Catches in the gillnets with the lowest han ging ratio (E = 0.25) were always higher than in the conventional gill nets (E = 0. 50). Catches of pikeperch were higher in the multifilamen t nets, those of bream were higher in the monofilament nets. Lowering the hanging ratio in the conventional nets to 0.25 always resulted in a higher mean length of fish caught.