...Because the golden eggs in my hand today is better than the goose that might be someone else's tomorrow? Fisherfolks across the world had absolutely no problem "killing the goose", depleting the stocks and denying there was any problem right up until entire sectors collapsed.
A lot of the threat to animals is the destruction of their habitat; allowing lucrative trophy hunting creates an incentive to not turn a giraffe's habitat into a golf course or luxury resort or whatever. https://news.nationalgeographic.com/news/2007/03/070315-hunt...
The case of fisheries seems more complex because there you have multiple actors each of whose actions will have little effect on the overall fish population but who cumulatively can devastate it.
This is exactly what happens, I've seen it first hand. The land is kept is more of a natural state to preserve it for hunting. Some are hunted for trophies etc., but the numbers that are taken are controlled so that you have another batch the next year.... keep in mind that many of these places are huge (100's of acres) with high fences etc. and becuase each animal has a dollar value, more common species usually start at $400 (Bleisbok) and can go up to $50,000+ for Cape Buffalo the economic incentive to preserve the speces is pretty strong... and lucrative.
