Life History of the Cutthroat Trout, Salmo Clarki Richardson, in Logan River, Utah
- 1 January 1952
- journal article
- Published by Oxford University Press (OUP) in Transactions of the American Fisheries Society
- Vol. 81 (1) , 235-248
- https://doi.org/10.1577/1548-8659(1951)81[235:lhotct]2.0.co;2
Abstract
This study of the cutthroat trout in Logan River, Utah, was based on 306 specimens collected during 1948 and 1949 with an alternating‐current electric shocking machine. Cutthroat trout composed 24 percent of the anglersˈ catch during 1948 and 31.5 percent in 1949. The greatest numbers were found in areas with a high stream gradient. An estimated minimum number of 43.6 pounds of cutthroat per acre and 565 fish per mile was obtained from a series of shocking operations during 1949. Scale analysis was employed in determining the age of the fish. With a scale magnification of 50x, the body‐scale (L/S) relationship of the cutthroat trout can be described as a curvilinear regression line, and expressed by the equation:L = 3.411 S1.2006The smallest average annual growth increment was 53 millimeters. This was based on a growing season of approximately 200 days. Growth began in the latter part of March and extended to early October. The relationship between standard length and weight was expressed mathematically as:W = 4.344 × 10−5 L2.8253where W equals weight in grams and L equals the standard length in millimeters. The coefficient of condition decreased as the length of the fish increased. Male cutthroat trout had slightly more weight per unit of length than females. Of 142 fish marked with jaw tags, 15 were recovered; none moved out of the one‐tenth‐mile area where they were originally released. The spawning period of the cutthroat trout in this area lasted from early April to the middle of August, but most fish spawned before the middle of July. Adult females ranged in size from 11 inches downward. Slightly more females than males were present in a total of 35 separate collections. Insects were the main item in the diet of the Logan River cutthroat trout. Ephemeroptera, Trichoptera, and Diptera were the principal aquatic orders taken, while the most important terrestrial order was Coleoptera. Small numbers of fish eggs eaten indicated that survival was not affected. Only two occurrences of fish were found in the entire food habits study. The small size of the cutthroat trout in this area is in part attributable to the almost total absence of forage fish in the upper Logan River.This publication has 0 references indexed in Scilit: