Way back when salmon being returned was a rarity, efficient methods of removing the fish from the water included tailers & gaffs, indeed, once secured with either of these, the fish would be banked, bonked and bassed.
However, tailers are only really useful for salmon, as grilse don't usually have enough of an abrupt transition from body to tail (rather perversely called a 'wrist') for the wire of the tailer to hold on to the smaller fish properly.
Tailers, gaffs, knotted nets & other such barbaric methods are not really 'harmless', so limiting the potential for returning fish 'unharmed', and all have been banned in UK waters for some years.
That they are still legal in Ireland says a lot

, and if you're gonna kill the fish anyway, it wouldn't really matter if you used a pitchfork either!