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-45- SPAWNING POTENTIAL Game Eish) Experimental Spawning Beds In any consideration of game species to be stocked in the Flaming Gorge Reservoir, high priarity must_be assigned to its reproductive potential. Maintaining adequate populations of game fish in a reservoir of this size, in excess of 42,000 surface acres, by annual stocking would place a serious drain upon existing state hatchery facilities. In March, 1957, representatives of the .Utah Fish and Game Department and the Wyoming Game and Fish Department met to discuss basic fishery manage- ment problems for the Flaffiing Gorge Reservoir. One of the agreements emerging from .this meeting was that .the initial stocking policy be restricted to sal- monid species, preferably rainbow and kokanee. It was felt that since these species have migratory tendencies during spawning, the Green River proper and tributary streams within the impounded area could be utilized as natural spawn- ing sites. At the time of this meeting little was known of the reproductive potential in .the lower section of the Green River proper. The following egg experiments were conducted to determine this potential. Inital egg plants were restricted to eyed eggs only. If these were successful it was planned to use eyed eggs, kokanee in this instance, to establish spawning runs. Brown trout .eyed eggs were also used to provide a comparison of hatching success. The decision to use brown trout eggs was based on the fact that it was also a fall spawning fish, and availability of the eggs at the tiffie this segment of the project was initiated. On December 19, 1958, 2,800 eyed brown trout eggs were planted in the Green River imanediately above Big Island Bridge, Station No. 3 of this report. The eggs were hauled from the State Fish hatchery at.Daniel, Wyoming. A 10 gallon cream can was used to transport the eggs to the planting site. Water temperatures were, 46® F. at the hatchery, 55® F. on arrival at the planting site, and the stream temperature was 45~ F. The can containing the eggs was set in the stream for tempering, approximately 40 minutes. After tempering, the eggs were divided into three lots. Two of the lots contained 1,000 eggs and one contained 800 eggs. Quart jars were used to hold the eggs until they were planted. The artificial spawning redd was constructed by digging a trench per- pendicular to the stream flow, This trench was approximately 18 inches wide, 7 inches deep and 4 feet long. Water depth, from. surface to the stream bed, was 12 inches. Planting procedure .consisted of placing a plywood box 16 x 16 x 25 inches into the artificially constructed redd. This box .eliminated the effect of stream current on the buoyance of the eggs. Planting baskets, made of triple .warp mesh cloth, 8'~ x 3~ x 12 inches, .were filled approximately 2/3 with gravel and set in the trench, inside the planting box. Eggs were transferred to the baskets by holding a hand over the quart jar and inverti~ag it under water. The-hand was then withdrawn and the