Bycatch reduction in trammel net fishery for prawn (Melicertus kerathurus) by using guarding net in Izmir Bay on Aegean Coast of Turkey

The number of floats and hanging ratio of trammel nets were altered in two experimental nets and compared to a standard trammel net to determine the impact on reducing the bycatch of purple dye murex, mantis shrimp and crabs.  The first experimental net had more floats than the control net in addition to a guarding net and the second experimental net had the same number of floats as the control net, with the addition of a guarding net.  During the first trial only experimental net 1 and the control net were compared and in the second trial all three nets were compared.  During the first trial, the experimental net caught 17% fewer prawns, the target species, 44% fewer crabs and mantis shrimp and 49% fewer murex than the control net.  During the second trial, experimental net 1 caught 66% fewer crabs, 27% fewer mantis shrimp and 32% fewer murex than the control net.  Experimental net 2 caught slightly fewer prawns (2%), 51% fewer crabs, 17% fewer mantis shrimp and 26% fewer murex than the control net.