9458

• UCREFRP Catalog Number: 9458
• Author: National Park Service.
• Title: Workshop on Population Estimates for Colorado Pikeminnow and Humpback Chub.
• USFW Year: 2001.
• USFW - Doc Type: Fort Collins.
• Copyright Material: NO

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Abundance estimation

-- Closed-model capture-recapture methods used

-- The 2-3 pass sampling regime allowed program CAPTURE (White et
al. 1982) to estimate population abundance each year.

--Analysis assumes population closure over 6-8 week time period,
i.e., recruitment, mortality, immigration and emigration are negligble.

-- Model Mo, used for the upper reach, assumes constant probability
of capture among individuals and among sample occasions.

-- Model Mt, used for the lower reach, assumes constant probability of
capture among individuals but capture probability varies among
sample occasions. The two-pass regime mandated use of model
Mt in the lower reach.