8097

• UCREFRP Catalog Number: 8097
• Author: American Fisheries Society.
• Title: Proceedings of the 18th Annual Meeting, Colorado - Wyoming Chapter, American Fisheries Society.
• USFW Year: 1983.
• USFW - Doc Type: March 2-3, 1983.
• Copyright Material: NO

Table 3. Total lengths of stocked and natural largemouth bass captured
by electrofishing in Chatfield Reservoir, Colorado.
Year- Total length (rom) at age
class Origin 1+ 2+ 3+ 4+
1978 Natural 148 227 273 332
Stocked 128 229 286 364
1979 Natural 139 203 279
Stocked 131 240 296
1980 Natural 132 151
Stocked 120 161
1981 Natural 135
Stocked 123

Although it appears that stocking can increase year-class strengths in
Chatfield Reservoir, it remains to be seen if this increase is of importance
to the fishery. In Lake Blackshear, Georgia, stocked largemouth bass con-
tributed approximately 13% of the year-class in 2 years, however, there was
no significant increase in angler catch rates after the bass were recruited
to the fishery (Weaver 1979). Lawson and Davies (1977) concluded that stock-
ing 150-200 rom largemouth bass appeared to increase year-class strengths
in an Alabama lake, but suspected that fishing mortality led to a drastic
reduction in their numbers.
During 1982, no marked bass were revealed in angler catches, however,
few bass had attained harvestable size and identification of pigment after
a number of years is difficult to detect, if present at all. At this point,
it is not unreasonable to assume that angler catch will increase because
of the supplemental stocking. We have been successful in greatly increasing
bass year-class strengths in some years. In addition stocked bass should
have a susceptibility to angling equal to or greater than that of natural
bass. Total mortality on bass stocked in Chatfield Reservoir has been 50-60%
during the past 4 years and a reward tag study now in progress indicates
that exploitation on bass 200-300 rom in length is approximately 20-35%.
In 1983 a IS-in. (380 rom) minimum length limit went into effect for
bass in Chatfield Reservoir. Few, if any, marked bass will be expected
in angler harvests during the years the length limit is in effect.
The impact of stocked bass on the fishery will be evaluated in the future
by comparing angler catch rates during the period that stocked bass are
present in the population to angler catch rates after those bass have cycled
out of the population.

LITERATURE CITED

Fieldhouse, R. D. 1971. Results of stocking largemouth bass in Nassau
Lake. New York Fish and Game Journal 18(1):68-69.

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