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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When fish counts and gonad examinations indicate spawning activity

is maximal, the physical conditions of each area where spawning Occurs are

described by mapping each site with a series of transects encompassing

the area. At intervals along each transect, depth, velocity profile,

substrate composition and the presence or absence of fish and of eggs are

noted. The factors best predicting spawning site selection given the types

of areas available will be determined from this information. Comparison

of sites selected in at least two spawning populations where different

types of sites are available will enable more accurate determination of

true preferences of the species.

Spawning behavior is described by direct observations made by divers

at the spawning site. On a selected spawning site numbers of fish are tagged

early in the season and are counted during each seasonal timing census in

an effort to determine how long individual fish remain pn the spawning

grounds. Selected fish are also observed throughout the day while daily

activity patterns are monitored to determine frequency of spawning.

Fish are sampled throughout the spawning season and at intervals

throughout the year and all fish captured for other purposes are examined

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for gonadal development as well as age, weight and length. Comparison of

gonad weights and conditions will show if mature fish spawn every year.

Activities To Date

Field work began on June 10, 1980. Initial efforts were concentrated

on the St. Maries River as information indicated earlier spawning there than

in other area rivers. Long river sections were snorkeled and gill and

trammel nets were set each night in different areas to locate reaches used

by fish and to assess spawning condition. Areas where fish were apparently