Age, Growth, Maturity, and Sex Composition of the American Smelt, Osmerus mordax (Mitchill), of Western Lake Superior
- 1 October 1964
- journal article
- Published by Oxford University Press (OUP) in Transactions of the American Fisheries Society
- Vol. 93 (4) , 382-395
- https://doi.org/10.1577/1548-8659(1964)93[382:agmasc]2.0.co;2
Abstract
This study is based on 4,561 smelt collected in Chequamegon Bay, the Apostle Islands, the Brule River, and Superior Harbor, all in western Lake Superior. Commercial production in the Great Lakes (U. S. and Canada combined) reached a peak of nearly 16 million pounds in 1960. Production in Lake Superior has generally been small but increased during the 1950ˈs to reach 948,000 pounds in 1960. All 0‐group and spring I‐group smelt had scales with sufficient sculpturing to permit detection of the first annulus. Annulus formation began after 6 June in 1960. In 1961, all smelt had completed the annulus by 24 August. The body‐scale relation is a straight line with an intercept of ‐0.9 inch on the axis of fish length. The weight of western Lake Superior smelt increased as the 2.952 power of the length. A large range of length in each age group and resulting overlap of age‐groups II‐VI made length a poor index of age. Female smelt grew faster than males after the second year and dominated strongly in age‐groups IV‐VII. Both sexes made their best annual growth in length (3.3 inches) during their second year of life; the largest weight increments (0.74 ounce, males; 0.85 ounce, females) came in the third year. Best production from a commercial pound net in 1961 occurred when the sex ratios of spawning smelt were nearest 50:50. Spawning male smelt were consistently shorter than females and the average lengths of both sexes decreased as the spawning season progressed. Shortest mature smelt of each sex were 5.0 to 5.2 inches but the males are probably the first to reach 100 per cent maturity. All year‐old smelt were immature. Among 2‐year‐old fish, 40.7 per cent of the males and 17.7 per cent of the females had reached maturity. All smelt more than 2 years old were mature. Ovaries of 10 smelt contained an average of 31,338 eggs for fish 7.3 to 8.8 inches long.This publication has 0 references indexed in Scilit: