The survival rate of fertilized salmon eggs became as high as 80 per cent in New England aquaculture industry, but since 2000, salmon embryos began to die in large numbers and the average survival rate fell to about 50 per cent.
Previous studies showed that a range of factors could negatively impact egg quality and production, including nutrition, stress, temperature and the endocrine status of the female.
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.
A study conducted by the University of Maine (UMaine) has found that two hormones may play significant roles in achieving an 80 percent embryo survival rate.
Dr Heather Hamlin, professor of marine biology and aquaculture at UMaine, and PhD student LeeAnne Thaye, published an article about their findings in the journal Aquaculture Research.
For the past five years, Hamlin and Thayer have been taking tissue samples from Atlantic salmon ages 2–4 at three sites: the National Coldwater Marine Aquaculture Centre run by the U.S. Department of Agriculture at UMaine’s Centre for Cooperative Aquaculture Research in Franklin; and two sites owned by Cooke Aquaculture — a fresh-water breeding site in Bingham and a sea cage site in Eastport.
In their research, the scientists incubated fertilized eggs and monitored their development. What they watched for was the development of the embryos’ eyes in the bright orange eggs — a good indication that the egg will ultimately hatch.
Source: FIS // Original Article