3011

• UCREFRP Catalog Number: 3011
• Author: Beamesderfer, R. C. and T. C. Bjornn.
• Title: Habitat Selection, Spawning Behavior and Early Life History of Northern Squawfish with Inferences to Colorado Squawfish.
• USFW Year: 1980.
• USFW - Doc Type: Progress Report,
• Copyright Material: NO

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squawfish, bridgelip and largescale suckers, chiselmouth chubs (Acrocheilus

alutaceus), mountain whitefish, smallmouth bass (Micropterus dolomieui),

redside shiners, dace, sculpins, and miscellaneous salmonid species.

SPAWNING BIOLOGY

Objectives

Subopjectives addressed in an effort to describe the spawning biology

of northern squawfish include:

1. To determine seasonal and daily timing of spawning activity and

relate to changes in flow, temperature and visibility.

2. To determine physical characteristics of preferred spawning sites.

3. To describe spawning behavior qualitatively.

4. To quantify frequen~y and duration of spawning for individual

fisb.

5. To determine age structure, length-weight and gonadal development

patterns in a spawning population.

Research Rationale and Design

Seasonal timing of spawning activity is approached by two methods.

Fish numbers in spawning ~reas are estimated directly by divers swimming

standardized transects at frequent intervals throughout the spawning season.

Those direct observations are supplemented by sampling of fish over that

same period, examination of their gonads and comparisons of conditions and

gonadal somatic indices. In conjunction with these activities, flows,

water temperatures and turbidities are monitored before, during and after

spaWning activity. Seasonal timing is compared in at least two separate

populations of fish. Daily spawning activity patterns are determined by

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d~.... .~.a~~~~~pns ma~e by d~veFB thfgMlhdut the day for a number of days.