Growth and Reproduction of the Longnose Sucker, Catostomus catostomus (Forster), in Great Slave Lake

Abstract

A biological investigation of the longnose sucker, in Great Slave Lake, was carried out in 1950 and 1951. Specimens were obtained by use of gill nets and seines. Suckers taken along the south shore had a faster rate of growth than those in the more northern area. In both areas, males and females grew at the same rate in length and weight. Females lived longer and thereby became heavier. The average annual survival rate was 45%. The growth exponent was 2.88; the length-weight relationship, W = 0.000252 L2.88. Longnose suckers spawned in Hay River from the ice cover break-up in May to June 15. The water temperature did not exceed 59°F (15 °C). The majority of spawning-run fish were 10 to 12 years old. Although sexually mature at 7 years, no suckers younger than 9 years of age were found in the spawning run. Females contained from 17,000 to 60,000 eggs but may not spawn each year. Fingerlings from Hay River were 33 to 80 mm in length, and were in their first summer. They all had scales.