7321

• UCREFRP Catalog Number: 7321
• Author: U.S. Fish and Wildlife Service.
• Title: Fish and Wildlife Service Upper Colorado River Basin Technical Advisory Study Important Reach Analysis - CRFP.
• USFW Year: 1984.
• USFW - Doc Type: \
• Copyright Material: NO

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. YOY Coioradc squawfish are distributed throucnout the mainstem
Green River from R~ 0 to B~ 340. Concentration a~eas using the preceeding
criteria (~G.9 fish!10~~. etc.) RM G to 160 ana fr~m 200-290.

Major nursery areas in the Green River would extend frorr. R~ 0 to 340.

juvenile and Adult

Location:

Criteria were developed for designating juvenile and adult concentration
areas. These were:

1. Average catch per hour ele:trofish of 0.3 or greater;

2. For strata identified above, at least 50~ of the catch had to
be juvenile, adult, or both respectively.

Table 4 provides a summary of the data retrieval. Very high catch rates of
0.7 fish per hour or above were documented for adults in Strata E, F, G in the
Green and Z in the White, and for juvenil~s in Stratum A of the Green River.
Therefore, ! have designated those strata as high concentration areas.
Strata 8, E,-F, G in the Green Strata 4, 6 and 8 in the Yampa, and W, Z
in the White were desionated adult concentration areas. Stratum 5 in the
~ampa was rejected as an important area for adults because only one adult
was captured there, a radiotagged fish that was only moving through the
area. Stata A and B in the Green were designated juvenile concentration
areas. These areas are presented in Table 5. .

In determining these values. SSP data (1979-81) were combined with
1980-1984 spring collection data for RADIO, by weighing~according to the
number of fish collected between SSP and each respective year as follows:

(SSP) (0,) + (Radio eo) Cn~) + (Radio gl) Cn?) + ----
, "1 + n2 +~03 .-

This technique is not totally correct since MANAGE effort for 79-81 SSP
was calcuiated for a juvenile class of up to 400mm and the radio data was
calculated at the 450mm size. However, in view of the final numbers
resulting from the process the error is assumed to be very small.

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