Survival, growth, and yield of brown trout stocked as fingerlings in Hot Creek, California

Four groups of fin clipped brown trout (Salmo trutta) fingerlings were planted in Hot Creek over a six year period. Survival and growth were estimated by fall and/or spring mark-and-recapture surveys. Yield to the angler for two of the tour groups stocked was estimated by stratified random creel surveys. Fingerling survival from the midsummer stocking period to fall averaged 51 %. Overwinter survival from young-of-the-year to yearling fish averaged 49%. Angler harvest of two groups of fingerlings stocked at densities of 16,082 fish/mile averaged 1,704 trout/mile (10.6%) and 194 lbs/acre. Abundant cover and microhabitat suitable tor young trout, ice-free winters, and rapid growth were factors viewed as contributing to high yields. Results do not suggest a change is needed in the general policy of not stocking brown trout fingerlings in California streams. Results do show that fingerlings stocked in Hot Creek, and presumably other productive streams with abundant cover, can effectively fill a void created by limited recruitment. (PDF contains 24 pages.)

Composition and bulk properties of Dorset river gravels

Considerable interest has been expressed in the composition of the stream gravels, the movement of bed materials and the relationship of sediment composition, packing and siltation of void space to invertebrate ecology. In the autumn of 1982, freeze-samples of gravel were obtained in Dorset streams. Data were required on the depth of salmonid egg pocke and were part of a broader investigation of regional variation in the independent variables of salmonid fish length, gravel size, current velocity and the resultant dependent variable ~egg burial depth. The Dorset river gravels examined are bimodal. The grain size distribution may be resolved into two near-normal frequency distributions interpreted as representing a primary framework or lattice of gravel particles into which a secondary matrix population of sand particles has penetrated.

Infiltration of fine and coarse sand into an open-work gravel bed

The siltation of an experimental gravel bed, with three grades of sand moving in suspension and as bedload, was examined. The rate of infiltration of sand into the void space of the gravel was determined under differing conditions of discharge, water depth, and velocity (jointly expressed as variation in the Froude Number) and suspended sediment concentration. The downstream reduction in siltation from the point source was also examined.

A comparative note on the modus operandii of reservoir development in Republic of China and India

Principles adopted by China for the development of reservoir fisheries are discussed. Production of some of reservoirs of China with that of India is compared. The reasons for obtaining higher production in China have been recognised as: emphasis on utilization of all resources for food production; direct feeding; use of selected varieties of fast growing carps; keeping 15 pigs per hectare of water area for application of pig void and application of manure; production of fingerlings at the reservoir sites enclaving coves and bays; grading and removing obstructions from bottom; rational harvesting and stocking and improvement of reservoir shore areas as a whole. Some of these measures which could be implemented in Indian conditions are briefly described.