February 3, 2017 — It’s a mystery that has puzzled University of Maine assistant professor of marine biology and aquaculture Heather Hamlin and the salmon farming industry in New England: the decline in egg survival.
The survival rate of fertilized salmon eggs had been as high as 80 percent. But beginning in 2000, salmon embryos began dying in large numbers and the average survival rate fell to around 50 percent.
Previous studies have shown that a range of factors can negatively impact egg quality and production, including nutrition, stress, temperature and the endocrine status of the female. Until recently, businesses such as New Brunswick-based Cooke Aquaculture, which runs farming operations at several sites in Maine, knew little about why some of its eggs were dying and others were surviving, despite having come from same strain females, cultured under similar conditions.
Now a UMaine study has found that two hormones may play significant roles in achieving an 80 percent embryo survival rate. Hamlin and LeeAnne Thayer, a UMaine Ph.D. candidate in marine sciences, wrote about their findings in the journal Aquaculture Research.