Sex ratio of the American eel ( Anguilla rostrata (LeSueur)) in Newfoundland waters

• Published in: Canadian Journal of Zoology
• Main Authors: Gray, R. W., Andrews, C. W.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1970
• Subjects: Animal Science and Zoology; Ecology, Evolution, Behavior and Systematics; Newfoundland
• Online Access: http://dx.doi.org/10.1139/z70-082; http://www.nrcresearchpress.com/doi/pdf/10.1139/z70-082

The sex ratio of the American eel in Newfoundland was estimated from studies of 354 examples from two brackish water and three freshwater habitats in Newfoundland. Sections of each gonad were cut at 10 μ, stained with haematoxylin, and counterstained with eosin. The material was divided into four classes; namely, females, immature females, males, and undifferentiated eels. Females were found in both brackish water and freshwater areas, while only one male was present in the material.The state of maturity of silver eels leaving Topsail Pond in the fall was determined from ova diameters. Ova diameters ranged from 0.109 to 0.214 mm; the average was 0.165 mm. These results agree closely with those reported by Svärdson for migrating silver eels in Europe.