A cat person, Steve? Maybe this explains why we mostly agree, but have a definite tendency to yowl at each other! ;-) The canine / feline comes from me, Jon, purely as a matter of discussing domestication.

As for eco-systems, an interesting sidelight on that (or possibly not, and apologies for going tangential, PFR!) is the Grand Banks off of Newfoundland. The Canadian govt slapped a moratorium on fishing there in 1992, when it finally became convinced that the cod fishery had, essentially, collapsed - cod biomass was estimated to have fallen to about 1% of historical levels. Cod live for about 25 years and can reach over 200lbs. It should be fairly obvious to anyone that if, year on year, you keep taking thousands upon thousands of tons of cod out of the ecosystem; if anything above, say, 10lb gets fished; then it's going to change.

I cannot remember where I read it, but scientific opinion is that the GB has found a new equilibrium where cod is not the dominant predator and it's extremely unlikely that it will ever return to the former equilibrium. Presumably, few of the cod that are ever likely to come to the GB are ever likely to survive for more than a few years now; something else will eat them first. So your local eco-system will no doubt find a new balance & still be healthy, Steve. It just won't be as it was...