Let’s take a closer look at your positions. First of all, you are talking about two issues. One, the way in which fish are harvested for consumption. That is the issue at hand. The second issue you bring up is the ethics of catch and release which involves catching fish for the sport of it and is worthy of another debate, but does not apply to this issue.
You make your argument based on the assumption that a spear fisherman is going to take a “breeding stock fish”. The person taking a fish to eat, be it a spear fisherman or a hook and line fisherman, gill net fisherman, fish trap fisherman, long line fisherman, etc, are presumably going to be after the same fish i.e. one good to eat. The spear fisherman spears that one fish. The hook and line fisherman may have to catch numerous fish before he gets the one he wants to eat. Every time a fish is caught it suffers some damage, be it a hook in the gills, damage to its mouth from the hook, damage to it’s bladder from being brought up from deep water too fast or just fatigue from being caught. Some that are released survive, some do not. And, all of the other methods catch fish that are not desirable to eat and are discarded.
You go on to put blame on the “declining fish stock” to over fishing by both sport and commercial fishing. In an objective analysis of this, one must also take into consideration the damage to the environment from dredging, pollution from the increase in population on the land and the increased boat traffic and the pollution it brings. It is a big ocean out there and just because there might be less fish around Ambergris Caye does not lead me to the only conclusion that there are less fish. I think an argument can be made that fish move to a better environment.
You also bring up the issues of regulations and the limits which any fishery can sustain. But this applies to all that partake in the harvesting of the fish. If a fisherman is allowed to take, let’s say a limit of 10 fish, then I maintain that the spear fisherman will do less damage to the population in taking his 10 fish than any of the other fishermen for the reasons I have stated.
PS: Gaz, "I agree spearfishing should not be encouraged when we make our living off showing visitors the beauty of the underwater life".
Does this mean you do not serve "underwater life" to your guests or suggest that when they go into town for dinner they only order rice and beans or something that did not come from the ocean?