1.45 is quite a long spearing dive in the UK.
I average about 1.15 on working dives, but will occasionally push to 2 if the situation demands it.
I prefer to do shorter dives with shorter recoveries to maximise "bottom time per hour"
Always dive well within your comfort zone. Spearfishing is not competitive freediving, there are no prizes for holding your breath the longest!
The best training for spearfishing is..... to go spearfishing, fish knowledge and instinct are far more important than physical ability, breathold time or even fitness (although they all help!)
cheers
dave
www.spearo.co.uk