The nutritive ecology of Lac la Plonge and Canoe Lake

Abstract

The supply and circulation of nutrients to the lake biota are important factors governing lake productivity. Any study to determine the fish producing capacity of a lake must concern itself with the transfer of organic matter from one state to another in the food chain. The physico-chemical features of a lake are important to the extent that they control the supply of nutrients and influence the rate of circulation of food material within the lake. It was felt that the study of the nutritive ecology of Lac la Plonge and Canoe Lake would provide useful information regarding their relative productivities. Because fish production is of major economic importance, this study concentrated on the feeding habits and growth rates of the fish, the quantity and quality of the fish food, and the physico-chemical conditions believed to be important in governing the rate of production of this fish food. Conclusions have been drawn and recommendations made regarding the management of the fisheries resources of these lakes. During the summer or 1956 a preliminary investigation had been made of the lake by Messrs. D. C. Scott and Z. Kondzielewski. Most of their time was spent sounding the lake and these data are included in this report. In May, 1957, a field party of four established summer headquarters at Lac la Plonge. Sampling was begun on June 2nd and continued to September 5th. Most of the summer work was concentrated on Lac la Plonge; however, four visits to Canoe Lake were made during the course of the summer, each of approximately four days duration.