It's all about reflexes. In spearfishing a split second hesitation its a lot of time for the grouper to recognise the danger and disappear in the nearest hole.
[ame=http://www.youtube.com/watch?v=rc_RoLSVHNE]YouTube - Spearfishing - 1 sec reaction time[/ame]
[ame=http://www.youtube.com/watch?v=rc_RoLSVHNE]YouTube - Spearfishing - 1 sec reaction time[/ame]