Nitrogen stunning of rainbow trout

This study examined the use of nitrogen gas for stunning of Rainbow Trout. It was found that nitrogen could be used as an effective stunning method and that the strong aversive reaction reported for carbon dioxide stunning was not observed. Measurement of ATP, its metabolites and pH were carried out to evaluate the effects of nitrogen stunning on post mortem muscle biochemistry. This treatment was compared to percussive stunning and air asphyxiation. Post mortem ATP levels in nitrogen stunned fish (1.96 ± 0.36 lmol g)1) were significantly higher than for asphyxiated fish (0.2 ± 0.11 lmol g)1) but lower than values for percussively stunned fish (5.9 ± 0.89 lmol g)1). This work indicates that the use of gasses other than carbon dioxide for stunning of fish deserves further study.