9554

• UCREFRP Catalog Number: 9554
• Author: Monroe, L. and T. Hedrick.
• Title: Northern Pike ‎(Esox lucius)‎ Control in the Middle Green River, Utah 2001-2006.
• USFW Year: 2008.
• USFW - Doc Type: 109,
• Copyright Material: NO

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successful at sampling lower in the sampling reach near Wyasket Bottom (RKM 410; RM 255)

and the White River (RKM 396; RM 246). By 2004, however, the main concentration areas were

Brush Creek, Cliff Creek, Stewart Lake inlet and drain, Ashley Creek, and the general Jensen

area (Figure 1).

All northern pike captured from all middle Green River sampling projects were counted,

weighed (g) and measured (mm) for total length (TL). All nonnative fish were euthanized and

removed; native fish were released at the site of capture. Endangered fish species were scanned

for a PIT (passive integrated transponder) tag, tagged if needed, and then released near the area

of capture. Nonnative removal and evaluation efforts, which included tagging and marking

native, endangered and target nonnative fishes, were also being conducted by other researchers

and agencies in other areas of the middle Green River and Yampa River. Therefore, sampling

crews examined all native, endangered and target nonnative fish for tags or marks and recorded

pertinent information. This information was then reported to principal investigators as
appropriate and included in annual reporting.

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Catch Per Unit Effort

Catch-per-unit-effort (CPUE) was either calculated as fish/hour (electrofishing and

trammel netting) or fish/fyke-net night (fyke-netting) (one fyke net set out for one night and

usually left for a 24-hour period is equal to one fyke-net night). Fyke nets set for shorter periods

of time were recorded in tenths of a fyke-net night for purposes of calculating CPUE. No

statistical analyses were performed on CPUE over the study period because removal efforts were

not done in a statistically consistent manner (removal efforts were not completed by pass, but

rather by distinct sampling occasions). Catch rates from the middle Green River were compared

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