Quelques aspects de la biologie du grand corégone Coregonus clupeaformis des lacs Hélène et Nathalie, territoire de la Baie James

Abstract

The life history of lake whitefish in lakes Nathalie (53°27′ N; 77°27′ W) and Hélène (53°27′ N; 77°31′W) was studied between June 1974 and November 1975. The age of 840 specimens was determined from the scales. Growth rates are very slow, compared only with those of dwarf whitefish of certain North American lakes. Food varies with the length of the fish and with the season of the year. Main food items are aquatic insects (larvae and adults), mollusks, and small fishes. In 1975, spawning occurred in late October (water temperature: 4 °C), at depths of 2–4 m; substrates utilized were sand, gravel, and boulders. Spawning lasted less than 2 weeks. Males mature at 390 mm (age 8) and females at 400 mm (age 9). Lake Nathalie whitefish (N = 41) show a low relative fecundity (17 980 eggs/kg). In the fall of 1974, the population density of Lake Nathalie whitefish 350 mm and longer was estimated at 839 individuals (0.72 kg/ha).