I agree that there's that potential, however, well managed fish farms that are run according to govt. regulations minimize the risk of farm raised fish getting out into the wild and interacting with wild stocks. The other aspect I think about when the farm vs wild debate comes up is that you simply cannot get people to up and quit eating fish, there will be a demand so instead of overfishing the oceans like we're doing now, the best alternative is to run fish farms to satisfy that demand, while letting the wild stocks regenerate in time.