Selectivity estimates for Amblygaster sirm (Clupeidae) in the small-meshed gill net fishery on the west coast of Sri Lanka

Abstract

Selectivity of Amblygaster sirm by gill nets of seven mesh sizes ranging from 2.3 to 3.8 cm stretched mesh was studied for a period of 12 months in the coastal waters off Negombo on the west coast of Sri Lanka. The size range of fish caught was 9.0-22.0 cm. Selection by mesh sizes smaller than 3.0 cm was towards the lower end of the selection curve. Estimated values for selection factors ranged from 5.11 to 6.03 and those for optimum selection lengths varied from 12.9 to 19.7 cm. The highest selection factor was observed for 2.9 cm mesh, probably due to wedging of larger individuals in this mesh. © 1991.