This study aims to bring to light
behavioral impairment and the delayed mortality of discards below legal catch rate
in a simulated trawl operation. Behavioral impairment of 126 fish in the
aftermath of trawling operation was tested in two different methods through
observing their reflexes. In the first method, all the fish in the tank was
compared with the control groups on account of their responds to different
stimulants, while in the second method, reflex measurement was individually
carried out. Reflexes from these two processes were taken as the extent of
behavioral impairment and a relation with delayed mortality was established. A considerable number of fatalities
among those returning to the water came about within 24 hours. There was a
proportional connection between behavioral impairment and delayed mortality.
However high the behavioral impairment might be, the mortality rate remained at
a certain proportion. A considerable number of fish survived under confined
medium in the laboratory tanks.