8099

• UCREFRP Catalog Number: 8099
• Author: American Fisheries Society.
• Title: Proceedings of the 21st Annual Meeting, Colorado - Wyoming Chapter, American Fisheries Society.
• USFW Year: 1986.
• USFW - Doc Type: March 5-6, 1986.
• Copyright Material: NO

multiplying each estimate by the attributable distance and area which were considered similar
habitat (0.34 miles for Station 1 and 0.72 miles for Station 2) and then summing the results to get one
estimate for the area. Both population and creel survey estimates were then adjusted to standard units

of number per mile and pounds per acre.

RESULTS

Sand Creek, on Ranch A, represents a section of stream which is at its carrying capacity. Prior
to the first fishing season in 1985, Sand Creek was unexploited and, therefore, only regulated by
environmental and/or density dependent factors. Carrying capacity was reflected in the dense trout
population estimates for Stations 1 and 2 in November 1984 and April 1985, prior to the fishing
season (Table 1). These estimates indicate trout carrying capacity (or maximum estimated density) of
6,650 trout/mile and 1,010 pounds/acre at Station 1 in April 1985. At Station 2, the highest estimates
were 4,247 trout/mile in April 1985 and 658 pounds/acre in November 1984 (Table 2).

Table 1. Trout population estimates at Station 1, Sand Creek, Ranch A.

November 5, 1984 April 30, 1985 November 11, 1985
Number/Station 364 369 250
(s.e.) (25.0) ( 1.5) ( 6.6)
Capture Probability* 0.554 0.927 0.757
Number/mile 6,559 6,650 4,505
Pounds/acre 979 1,010 641
Brown:Rainbow 88:12 88:12 91:9
*Capture probability l-C2/Cl (Armour et al. 1983)

Table 2. Trout population estimates at Station 2, Sand Creek, Ranch A.

November 5,1984 April 30, 1985
Number/Station 165 185
(s.e.) (11. 7) ( 3.1)
Capture Probability* 0.614 0.847
Number/mile 3,788 4,247
Pounds/acre 658 547
Brown:Rainbow 96:4 99:1

November 11, 1985

147
( 6.6)
0.714
3,375
348

99:1

*Capture probability l-CZ/Cl (Armour et al. 1983)
8