University of Maine assistant professor of marine biology and aquaculture Dr Heather Hamlin has been studying why the survival rate of salmon eggs in hatcheries has declined by as much as 50% in the last 18 years. And now Hamlin and Ph.D. candidate LeeAnne Thayer may have gone some distance to solving the problem.
January 29, 2018 By Quentin Dodd
Earlier this year a paper published in Aquaculture Research reported that the researchers had identified two hormones that may play a role in governing egg-survival rate.
Hamlin and Thayer collected tissue samples from Atlantic salmon ages 2-4 from three sites: the National Coldwater Marine Aquaculture Center, and two sites owned by Cooke Aquaculture.
Focusing on the endocrine system, the team found that female salmon with the highest levels of 11-ketotestosterone (11-KT) an androgen, and 17ß-estradiol (E2) an estrogen, were more likely to produce embryos with an 80% survival.
Perhaps boosting these hormones in the female hatchery broodstock could increase survival. The team was cautiously optimistic that this could be the case, and had been continuing their research.
In the meantime, they are helping producers adjust their breeding programs by taking hormone levels into account. Adding hormones to fish doesn’t please either consumers or regulators, but there might be ways to encourage the fish to produce more of these key compounds or breed fish with higher levels of them.
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