Skinning and Trimming.

 With time, practice and patience I have learned to remove the fat, red muscle, and bloodline revealing the pure flesh of the fillet. It's the red muscle and bloodline that can leave a 'fishy' flavour and detract from the pure flavour of flesh and smoke.

The immense sharpness required of the knife means that I'm only able to finish one fillet without re-honing the blade !