Farm salmon pose clear reproductive threat to wild gene pools
Posted: March 10, 2014 at 3:42 pm
PUBLIC RELEASE DATE:
9-Mar-2014
Contact: Lisa Horton l.horton@uea.ac.uk 44-016-035-92764 University of East Anglia
Farmed salmon show full reproductive potential to invade wild gene pools and should be sterilised - according to new research from the University of East Anglia (UEA).
Findings published today reveal that, while farmed salmon are genetically different to their wild counterparts, they are just as fertile. This is important information because millions of farmed salmon escape into the wild posing threats to wild gene pools.
Lead Researcher Prof Matt Gage from UEA's school of Biological Sciences said: "Around 95 per cent of all salmon in existence are farmed, and domestication has made them very different to wild populations, each of which is locally adapted to its own river system.
"Farmed salmon grow very fast, are aggressive, and not as clever as wild salmon when it comes to dealing with predators. These domestic traits are good for producing fish for the table, but not for the stability of wild populations.
"The problem is that farmed salmon can escape each year in their millions, getting into wild spawning populations, where they can then reproduce and erode wild gene pools, introducing these negative traits.
"We know that recently-escaped farmed salmon are inferior to wild fish in reproduction, but we do not have detailed information on sperm and egg performance, which could have been affected by domestication. Our work shows that farm fish are as potent at the gamete level as wild fish, and if farm escapes can revive their spawning behaviour by a period in the wild, clearly pose a significant threat of hybridisation with wild populations."
Researchers used a range of in vitro fertilization tests in conditions that mimicked spawning in the natural environment, including tests of sperm competitiveness and egg compatibility. All tests on sperm and egg form and function showed that farmed salmon are as fertile as wild salmon identifying a clear threat of farmed salmon reproducing with wild fish.
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Farm salmon pose clear reproductive threat to wild gene pools