Lake-Management Studies in Oregon

Abstract

This paper presents the results of creel censuses being carried out on four major lakes in Oregonˈs Cascade Mountains. The study on one lake commenced in 1945 and on the other three in 1946. The fish population of one of the lakes, 130 acres in area, was removed by poison in 1941; all plantings of rainbow trout (Salmo gairdnerii) since that time can be identified in the catch. Two of the lakes of approximately 1,000 acres each are stocked annually with rainbow and eastern brook trout (Salvelinus fontinalis) and the fourth of approximately 3,000 acres is stocked annually with rainbow trout fry produced from an egg-taking station at the lake. The primary objectives of the creel-census studies are to determine proper stocking policies and other management techniques to meet the great increase in fishing pressure not only on these but on many similar waters. Significant disclosures thus far include a decrease in average size of fish taken that is attributable to the heavy fishing pressure and in one lake in particular, to the presence of a large population of Klamath chub (Siphateles bicolor) which are competing for the available food supply. Data are at hand which illustrate the poor results in terms of survival from fall plants of fingerlings 3 to 4 inches long as compared to spring plants of fish 5 to 7 inches long. Another disclosure of interest is the sharp drop that occurs in the take of spring-planted fish the year following planting.