I think I'd be more concerned about the environment than the effect on people. They make people fat and we lose a few people; destroy the fishing grounds of our coasts and we could lose a lot more.
This reminds of something from years ago, when the community I lived in was having a problem with algae and weeds in their lakes. A sister community a few miles away had had the same problem and had purchased some kind of Chinese carp; they asked if we wanted some.
They were genetically triploid, so couldn't reproduce; they would live out their natural lives and die. Vegetarians, you couldn't catch them on a hook and line but they were voracious eaters.
We were interested, until we visited and talked to the residents there. The darned things did reproduce and grossly overpopulated their lakes. The lakes were nearly dead - it seems they would eat other fish if that's all there was and at 4' long they were far larger than the bass and perch in the lake. As the lakes died they began to walk out of the lake and eat the flowers and shrubs in the resident's flower beds. Don't know if it's true, but we heard reports of small pets being killed by the things. That one was probably a tall tale, but we did see destroyed flower beds with trails to the lake as well as some very large specimens.
Any changes in the ecosystem is to be approached very, very carefully, and growing only female fish doesn't seem wise.
