That's why critics say transgenic fish might be appropriate only for land-based tanks, where escape is impossible. So far those systems have not proved cost-effective. Meanwhile Stevens continues to breed larger, stronger fish the traditional way. Genetic engineering for him is just a way to speed that process. Given enough time, hatcheries can match most advances pioneered in a laboratory, he says.
Selective breeding goes back a long way.
Genetic engineering isn't that different from what we're already doing.