Paul R. Needham

Ecological Effects of Winter Conditions on Trout and Trout Foods in Convict Creek, California, 1951

Abstract In 1951, winter studies were conducted at the Convict Creek Experiment Station of the U. S. Fish and Wildlife Service located at 7,200 feet elevation in the Sierra Nevada Mountains near Bishop, California. These were designed to extend knowledge of winter conditions in stream environments and to bring to light problems requiring further investigation at this season. Common stream survey methods were employed to procure and analyze data. Snowfall was meager at Convict Creek in 1951, but freezing temperatures induced extensive ice formations. Surface ice immobilized screens and other objects protruding from the water, yet provided the trout with abundant shelter. Frazil and anchor ice had a more pronounced effect on stream life and water temperatures than surface ice. When subsurface ice was present, the water was at or very close to the freezing point, regardless of weather conditions or time of day. Anchor ice formed and dispersed in a daily cycle that caused wide fluctuations in stream flow. Min...

Survival of Hatchery-Reared Brown and Rainbow Trout as Affected by Wild Trout Populations

MARTIN, A. C., and F. M. UHLER. 1939. Food of game ducks in the United States and Canada. U. S. Dept. Agric. Tech. Bul., 634. 156 pp., illus. MCATEE, W. L. 1918. Food habits of the mallard ducks of the United States. U. S. Dept. Agric. Bul., 720. 36 pp., illus. 1939. Wildfowl food plants. Ames, Iowa, Collegiate Press, Inc. 141 pp., illus. PIRNIE, MILES DAVID. 1935. Michigan waterfowl management. Lansing, Mich.. Michigan Department of Conservation, 328 pp., illus. RICKETT, H. W. 1921. A quantitative study of the larger aquatic plants of Lake Mendota. Wis. Acad. Sci. Arts and Let.,Trans., 20: 501-527. 1924. A quantitative study of the flora of Green Lake, Wisconsin. Wis. Acad. Sci. Arts and Let. Trans., 21: 381-414.

A New Trout from Central Mexico: Salmo chrysogaster, the Mexican Golden Trout

distinctive characters had a genetic basis and were not mainly phenotypic expressions of local environmental phenomena. The compilation of data by Needham and Behnke (unpublished) on more than 2,000 specimens of the genus Salmo from western North America, collected from virtually their entire native range, has demonstrated that, indeed, the Mexican golden trout is a distinct group and worthy of taxonomic recognition. Taxonomic methods used are essentially those listed in Hubbs and Lagler (1949) with the modifications noted in Needham

Survival of Trout in Streams

Abstract In spite of extremely heavy expenditures for rearing of hatchery fish, the angling continues to decline. Millions of fish are wasted each year because of lack of facts on how best to utilize properly the product of hatcheries. Survival studies have indicated that under natural conditions, wild brown trout suffer tremendous natural mortalities amounting to 85 percent in the first 18 months of life. Overwinter mortalities averaged 60 percent over a 5-year period. Variable survival conditions rather than the number of young produced in any year, determine the number of fish that later reach catchable size. Survival studies of hatchery-reared trout indicated heavier losses than with naturally spawned fish. Creel-census returns from a number of different waters are presented to support this fact. The conclusion is reached that the angling public must be made aware of the basic economics of hatchery operation, its costs, successes, and failures in order that the field of fishery management again may mo...

Notes on the Introduction of Salmo Nelsoni Evermann into California from Mexico

Abstract Through the courtesy of the Mexican Government, fifty yearling Salmo nelsoni were introduced into California from the Santo Domingo River in Lower California, Mexico, in May, 1937. The chief reasons for the selection of this species of trout for experimental brood stock purposes are (1) the need of developing a non-migratory type of trout for planting, (2) the advisability of starting with a brood stock selected from a pure, wild strain which has been prevented by barriers from migrating to the sea over a long period of years, and (3) the high temperature tolerance shown by this trout in its natural habitat. A brief history of the species is given. A distinct hump on the back, directly above the preopercle at the base of the head, hitherto not described, is suggested as a character by which S. nelsoni may be distinguished from other members of the rainbow series found in the coastal waters of California.

Quantitative and Qualitative Observations on Fish Foods in Waddell Creek Lagoon

Abstract Seasonal studies of bottom foods were made in Waddell Creek Lagoon in 1932, 1933, and 1934. Quantitative samples were taken both with an Ekman dredge and a square-foot box. The numbers of organisms per square meter and pounds of food per acre are based on recalculations of results obtained from the unit areas sampled. The most abundant bottom populations by weight were found in March, and the least in November. Dominant animals were three crustaceans: two amphipods, Gammarus confervicolis and Corophium spinicorne, and one isopod, Exosphaeroma oregonensis. These are brackish water forms and almost completely replace typical fresh-water forms in the inter-tidal areas in Waddell Lagoon. Steelhead trout were found to eat large numbers of Gammarus, considerably less of Exosphaeroma, while no Corophium were found in the stomachs examined. A summary of results is given at the end of the paper.

Fishery Research at Mid-Century

Abstract In North America fishery research is approached by almost as many administrative avenues as there are agencies engaged in it. Between these agencies differences exist in needs, plans, staff organization, methods of enlisting public support, and in the application of research findings. This situation is desirable. In the comparative infancy of fishery science any tendency toward development of stereotyped doctrine should be deplored. Originality and eclecticism should be encouraged, both in training institutions and in research and administrative bodies. An objective review of apparent successes and failures to date, however, may prove of value in illuminating pitfalls and in pointing out procedures which have resulted in progress. From this review profitable methods and promising areas for future activity may be inferred by the reader.

The Western Angler, an account of Pacific salmon and Trout

Abstract By Roderick L. Haig-Brown: Two Volumes, Vol. I - 200 pp.: Vol. II - 192 pp.: Derrydale Press, New York, 1938.

Variability in the macrofauna of a single riffle in Prosser Creek, California, as indicated by the Surber sampler

25.00 set.