7733

• UCREFRP Catalog Number: 7733
• Author: McAda, C. W.
• Title: Evaluation of Aerial-Video Measurement of Backwaters as Part of the Interagency Standardized Monitoring Program for Age-0 Colorado Squawfish.
• USFW Year: 1993.
• USFW - Doc Type: \
• Copyright Material: NO

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United States Department of the Interior
FISH AND WILDLIFE SERVICE
COLORADO RIVER FISHERY PROJECT
gad , a" 529 25 % ROAD, SUITE B-110
GRAND JUNCTION, COLORADO 81505
IN REPLY REFER TO: [phone]
FFA 65332 February 23, 1989
MEMORANDUM
TO: Meeting attendees and interested parties
FROM: Chuck McAda, Fishery Biologist, Grand Junction
SUBJECT: Review of Interagency Standardized Monitoring Program
¦
TAKEfr
"RE

The following is a brief summary of the group consensus from the meeting held in Grand
Junction on February 16. Please let me know if your recollections are significantly
different than those recorded here.
Young-of-the-year Colorado squawfish monitoring
- The current monitoring reaches encompass 70 and 80 percent (Green and Colorado
rivers respectively) of the known range of YOY Colorado squawfish. These sampling
reaches are adequate for the purposes of the monitoring program.
- We will explore the possibility of using video equipment operated from a helicopter to
quantify the number and size of backwaters available when monitoring occurs. Field
workers will not attempt to count the number of backwaters as they proceed
downstream.
- The criteria for selection of suitable backwaters will be modified to allow sampling of
backwaters shallower than 1 ft (at the deepest point) if the backwater is turbid enough
that the bottom of the backwater cannot be seen.
- The two seine hauls in each backwater must be made through the turbid portion of the
backwater when clear water exists in the upper end of the backwater.
- The area sampled by the two seine hauls need not comprise 25% of the area of the
backwater. I will compare catch rates from backwaters where area seined was less
than 25% with backwaters where area seined was 25% or greater to determine if
important differences exist.
- Subsampling of fishes in seine hauls should not be done on a routine basis. However,
unusual situations involving inordinately large numbers of fish may require subsampling
of the total fishes collected to minimize injury to Colorado squawfish. It will be the
responsibility of the individual researcher to determine when subsampling is necessary
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