Spearfishing - is it ecologically sustainable?

Spearfishing or underwater fishing is an activity that generates emotion and debate. Is it the most ecologically sustainable method of catching a fish or is it an activity of environmental vandalism and needless slaughter? Proponents argue that spearfishing is ecologically sustainable because a diver is restricted to shallow water, a diver is very selective and can target the size and species of his\her capture without the negative impacts of other fishing methods such as bycatch, bait, loss of gear and damage to habitat.