If you had a farm covering a greater area than all the land on earth with that many cattle then you'd be seriously thinking about a new career. Not to say of course that whales should be packed into feed lots... but the ocean is a very large place.
I believe Cod numbers in the North Atlantic have achieved very little growth since they stopped being fished, most likely because of the likelihood of enough of the survivors meeting is quite low.
Respect for the ocean extends to what lives in it too. With the trawling example, which is an incredibly inefficient use of a fragile resource