Selectivity of multifilament trammel and gillnets for common carp (Cyprinus carpio L., 1758) in Lake Marmara

Abstract

This study was aimed to estimate the selectivity properties of multifilament trammel and gillnets for common carp ( Cyprinus carpio L., 1758) in Marmara Lake in Manisa, Turkey. Trammel and gillnets of 4, 6, 8, and 10 cm stretched mesh size and 210 d/2 no twine thickness were tested in the Marmara Lake. In addition, selectivity parameter of 11, 12, 13 and 14 cm mesh size of trammel and gillnets were modelled. SELECT method was used to estimate the selectivity parameters. Experiments were carried out monthly in the three different stations identified eastern, middle and western areas which represent longitudinal length of the lake. A total of 36 trials were conducted both nets. A total of 119 common carps were caught ranges between 11.3 - 49.0 cm total lengths. According to the Bi- normal model, which gave the lowest deviance for both trammel and gillnets, selectivity curves were estimated for 4, 6, 8, 10, 11, 12, 13 and 14 cm stretched mesh size modelled lengths as 12.98, 19.47, 25.96, 32.45, 35.70, 38.94, 42.19 and 45.43 cm for trammel nets, 12.40, 18.60, 24.80, 31.00, 34.10, 37.20, 40.30 and 43.40 cm for gillnets, respectively. When considering minimum landing size (40 cm total length), it is recommended that both nets under 13 cm mesh size should be prohibited for common carp fishery in the Lake Marmara. Keywords: Trammel net, gillnets, common carp Cyprinus carpio, size selectivity, Lake Marmara