8290

• UCREFRP Catalog Number: 8290
• Author: Day, K. S. and C. Crosby.
• Title: An Assessment of Young-of-the-Year Colorado Squawfish ‎(Ptychocheilus lucius)‎ Use of Backwater Habitats in the Green River, Utah.
• USFW Year: 1997.
• USFW - Doc Type: FG-33,
• Copyright Material: NO

effect of flows on backwater habitat availability and Colorado squawfish produ
reports, however, primarily address summer flows. Pucherelli and Clark (1989)
increase in backwater area in Island Park and below Split Mountain as peak flo
Backwater habitat was maximized, they reported, if flows were decreased gradua
between 1000 cfs and 1800 cfs at the Jensen gage. The system is obviously mor
this simple model would suggest. Summer and winter flows have a great impact
availability, particularly in the spring. Spring flows do scour and move sedi
primarily depositional. Lower flows later in the year sculpt the deposited ma
habitats available for YOY fish (J. Schmidt, pers. comm. The importance of
reestablish habitat should not be overlooked, however. Habitat availability a
tied to a serious of flow events over time. Pucherelli, Clark and Szabadou (1
numbers of backwaters per river mile and backwater area per river mile are hig
year to year because of channel morphology and changes therein. Hlohowsky and
suggested that seasonally adjusted high flows would provide the most nursery h
therefore, potentially increase recruitment. They cautioned, however, that th
also increase overwinter mortality. They, further, reasoned that seasonally a
steady flows would benefit native fish the most and that year-round high fluct
most detrimental.
That no relationship could be detected between Colorado squawfish number
spring peak flows was not expected. Timing and success of spawn for all endem
fish have been tied to the natural spring hydrograph and associated water temp
1986). Beyond this, McRda and Keading (1989), Haines and Tyus (1990), Tyus an