An evaluation of the effects of three marking techniques on the growth, behavior, and mortality of channel catfish (Ictalurus punctatus (Rafinesque)

Three groups of fingerling channel catfish, Ictalurus punctatus (Rafinesque), were marked using either a partial fin clip of the left pelvic fin, a cold brand using liquid nitrogen at -196°C as a coolant, or a gun-injected spaghetti-type floy tag. Fish were observed during a 12-week period and compared to a control group for loss of marks, noticeable change in behavior, mortality attributed to the marks, and any significant effect that the marks exhibited on growth. It was determined that the cold brand was the only marking technique producing a mark that was still retained by the fish and recognizable after a 12-week period. Behavior was greatly altered only in the group receiving the injected tag; this group also exhibited the only substantial rate of mortality attributed to the mark. Statistical analysis of the effects of the three marking techniques on growth indicated that the application of the marks had no significant effect on those fish surviving throughout the experimental period.