Size and ATP Content of Unfertilized Eggs from Farmed and Wild Atlantic Salmon in Newfoundland

Abstract

In Newfoundland and Labrador (hereafter, Newfoundland), all farmed Atlantic Salmon Salmo salar originate from the Saint John River, New Brunswick, strain, raising the question of potential impacts of escapees on wild, genetically distinct stocks. Unfertilized eggs of farmed and wild salmon were assessed for diameter, mass, adenosine triphosphate (ATP) content, and fertilization success, this is the first study to assess ATP content in Atlantic Salmon eggs. Results demonstrated that farmed salmon egg mass (0.1046 g), diameter (6.2 mm), and ATP content (0.0281 nmol/egg) were significantly lower than the same characteristics in wild salmon. Among and within females, variability in egg size was similar in both wild and farmed groups. This study lends some evidence to the fact that in the Newfoundland context, eggs of escaped farmed salmon may be less likely to produce viable, large larvae compared with their wild counterparts.

Sperm traits in farmed and wild Atlantic salmon Salmo salar

“…() found no differences in fertilization attributable to a difference in gamete traits, while the trend observed in this study and the results of Lush et al . () highlight an egg quality effect despite a very high sperm to egg ratio. Despite the dissimilarity in fertilization rates, the present data confirm Yeates et al .…”

“…Lush et al . () showed that the variability of egg mass among females was equivalent in both Saint John strain farmed and Little River wild females. In addition, variation in ATP egg −1 revealed differences between wild and farmed S .…”

“…Lush et al . () found significant differences in fertilization success and egg size (mass and diameter) and quality (energy amounts egg −1 ) when comparing Little River wild females and Saint John strain farmed females crossed with the same males. In Lush et al .…”

“…In Lush et al . (), the authors compared eggs from 12 farmed and 22 wild females. Taken together, these results suggest a low contribution of sperm quality and origin to the observed fertilization success rates.…”

“…In addition, variation in ATP egg −1 revealed differences between wild and farmed S . salar with a c.v. of 8·54 and 40·24% for farmed and wild females, respectively (Lush et al ., ), raising more questions on the higher s.d . observed in fertilization rates of farmed females.…”