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 2. Comparison of expected lot sizes and actual first inventories.
*
Lot # and Group Expected Lot Size First Inventory % Difference
Fall Rainbow
Lot 20-82
Group A 50,496 51,579 +2.1
Group B 50,513 52,832 +4.6
Control 50,600 55,837 +10.3
EnUre Lot 303,615 313,110 +3.1
Fall Rainbow
Lot 21-82
Group A 47,352 46,601 -1.6
Group B 47,403 44,988 -5.1
Control 47,322 47,520 +0.4
Entire. Lot 283,488 278,196 -1.8
Brown Trout
Group A 47,034 41,632 -11. 5
Group B 47,055 44,109 -6.3
Control 47,080 44,539 -5.4
Entire Lot 380,320 345,450 -9.1

*
Computed by subtracting cumulative mortalities from the original stocking
rate.

Another parameter tested was a comparison of recorded (or "expected")
lot size with the actual lot size at first inventory. It was expected that
the test groups would show less variation between expected lot size and actual
inventory, but again the results were inconclusive (Table 2). In fact, the
first inventory of lot 20-82 fall rainbow showed a 3% overrun of the expected
lot size. Our superintendant had expressed concern in the past that we were
not accurate enough in keeping track of mortalities in the early life stages,
and it was hoped that this sorter would provide a practical way to more effec-
tively account for some of this mortality. Such was not the case.
As mentioned before, inherent restrictions in the use of the sorter
necessitated employing four sub-groups of fry per lot, which were dumped on
successive days. Observations of feeding behavior and initial mortalities
served to reaffirm traditional dumping dates for both fall rainbow and brown
trout. To wit, at the 520F temperature of Clark's Fork's water, fall rainbow
are sufficiently trained to feed after 7 to 8 days in the baskets from ini-
tial feeding date, and brown trout are trained in 12 to 13 days.

CONCLUSIONS AND RECOMMENDATIONS

Perhaps the most obvious conclusion that can be reached from this experi-
ment is that experimental animals, when given the opportunity, will do what-
ever they please. Aside from that, there are some other less obvious con-
clusions. First, the fry sorter does work to some degree; it provides for

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