The rivers involved were Indian River, Exploits River, Conne River, and Little Salmonier River. A reduction in the number of eggs between summer and fall was attributed to atresia. The onset of atresia has been attributed to adverse environmental conditions resulting in stress, among which is water temperature. During the summer of 1987, severe drought conditions affected most rivers in Newfoundland, including Conne River. Sustained low water levels and high water temperatures in 1987 could explain the high rate of atresia observed for this river.
Results show that atresia can occur to varying degrees depending on environmental conditions.
Fecundity values derived from ovaries collected in the recreational fishery therefore have to be regarded as potential and their use could result in underestimates of conservation spawner requirements and overestimates of egg depositions.