This is the case. The same goes for rabbits, pigeons, etc. They are plentiful enough and you can live on them, but if 60M people did they would be in short supply soon enough. I can't see many people would object to eating a wild caught rabbit. One minute it's lolloping along, minding its own business, the next, bang, done. It doesn't know whether it's just met a fox or a bullet. It's not being wasted, and I am sure that we could kill as many rabbits as we could find and they woukd still be plentiful.My guess is that venison would only equate to a tiny proportion of the amount of beef consumed here?
The same applies in the sea. Apparently the N Atlantic is now filling up with Japanese Spider Crabs, they are non-native and invasive. Delicious too, apparently, the Japanese love them. However we can't catch them as there is no quota for them. Meanwhile we have to limit cod and haddock catches to allow the population to remain stable. It's about time we persuaded more people to eat pollack, whiting, and other unloved UK native fish.