Study on the size selectivity of a gillnet for herring (Sardinella jussieu) in the coastal waters of Nghe An province
Abstract
The study used the Holt (1963) method to determine the size selectivity of gillnet for herring (Sardinella jussieu) with different mesh sizes. Five types of gillnet with 24, 26, 28, 30 and 34 mm mesh sizes were conducted in the coastal waters of Nghe An province, from March to April 2022. 50 trial batches were collected with a total of 2,054 samples of herring. The result showed that the optimum catch length of herring caught by gillnet with 24, 26, 28, 30, and 34 mm mesh sizes as 100.5, 108.8, 117.2, 125.6 and 142.3 mm, respectively, common selectivity factor (SFc) as 4.19 and common standard deviation (SDc) as 19.1. The length at first maturity of female herring (120 mm) was compared to the optimum selection length of gillnet with mesh sizes of 24, 26, 28, 30, and 34 mm, which indicated that gillnets with mesh size of greater than or equal to 30 mm would be appropriate for catching herring in the coastal waters of Nghe An province.
