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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Table 1. Fork lengths (mm) of the largest and smallest mature individuals,
average lengths of mature fish and 95% confidence intervals for the
differences between mean lengths of mature fish of both sexes of northern
squawfish taken by gill net from three north Idaho rivers during spawning
in the spring of 1980.

St. Maries St. Joe Clearwater
River River River
Male Female Male Fema,le Male Female
Largest mature individual 415 490 320 530 370 450
Smallest mature individual 245 270 210 290 325 305
Mean lengths of mature 282 375 282 402 340 338
individuals
n 71 39 15 16 4 12
95% confidence intervals
for the difference 00.5, 115.5) (82.8, 157.2) (-77.2, 79.2)
in mean lengths

Future Activities

Known or suspected spawning sites 1n the s~. Joe and Clearwater rivers

will be checked at weekly intervals beginning the first week of June in

1981. The number of fish seen on each site while swimming standardized

transects will be recorded. Fish will also be gill netted during this

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period to check spawning condition. When appreciable numbers of fish begin

spawning, every site that can be located in each river will be mapped with

methods perfected during spawning and habitat selection portions of the

study in 1980.

In one site on each river. spawning activity will be observed through-

out the day on one day during peak spawning activity. On one site in the

St. Joe River, numbers of fish will be Floytagged with colored tags used

only on that site and their presence will be monitored to estimate how long

individuals remain on the spawning area. After mapping each area, fish

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will be seined and S~ will be sacrificed for the population study while

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