Effect of trammel net with different sizes of mesh of inside net on catching efficiency.

Abstract

Trammel net has been used widely in the coastal waters of the world. However, studies on the selectivity of trammel net have not yet been developed.In this paper the selectivity of trammel net was examined with the trammel net whose mesh sizes ranged from 3.6cm to 6.8cm for inside nets. The results obtained here are summarized as follows:1) The catching efficiency of trammel net with different mesh sizes of inside net was different by the species of aquatic animals.2) The selectivity curve of trammel net for konoshiro Konosirus punctatus was obtained by the methods of Ishida and McCombie & Fry. It showed that the optimum length of trammel net for konoshiro by the above two methods agreed with each other.3) The trammel net tended to select the small size of konoshiro severely, while in the large size of konoshiro it was not so severe. This was considered to be due to the effect of entanglement of fish by outside nets and/or inside net.4) Selectivity of trammel net for konoshiro did not seem to be so remarkable as compared with that of single wall of gillnet.