This study shows that when they raise fish in captivity and release the offspring into the wild, the offspring aren't as "fit" to reproduce. It's funny how it's all focused on genetics. Everyone knows farm raised salmon aren't as healthy and therefore as nutritious to eat as wild salmon in part because they are fed fish junkfood: corn (when's a fish going to eat corn in the wild?), antibiotics, dyes. Obviously, this happens to humans as well.
from Science Magazine:
Genetic Effects of Captive Breeding Cause a Rapid, Cumulative Fitness Decline in the Wild
Captive breeding is used to supplement populations of many species that are declining in the wild. The suitability of and long-term species survival from such programs remain largely untested, however. We measured lifetime reproductive success of the first two generations of steelhead trout that were reared in captivity and bred in the wild after they were released. By reconstructing a three-generation pedigree with microsatellite markers, we show that genetic effects of domestication reduce subsequent reproductive capabilities by 40% per captive-reared generation when fish are moved to natural environments. These results suggest that even a few generations of domestication may have negative effects on natural reproduction in the wild and that the repeated use of captive-reared parents to supplement wild populations should be carefully reconsidered.
Department of Zoology, 3029 Cordley Hall, Oregon State University Corvallis, OR 97331, USA.