9384

• UCREFRP Catalog Number: 9384
• Author: Valdez, R. A. and R. J. Ryel.
• Title: Summary of Recovery Goals for the Four Endangered Fishes of the Colorado River Basin.
• USFW Year: 2000.
• USFW - Doc Type: Logan.
• Copyright Material: NO

General - 1

GENERAL

Table 1. Estimates ofNg and MVP based on genetic effective population size (Ne)'

Species Ne Mb:Fb Mb Fb Nb N/N Ng M MVP
Humpback Chub 500 I : 1 250 250 500 0.3 1,667 0.20 2,000
Colorado Pikeminnow 500 3: 1 499 166 665 0.3 2,217 0.15 2,550
Razorback Sucker 1,000 3: 1 1,000 330 1,330 0.3 4;433 0.30 5,800
Bonytail 1,000 1: I 500 500 1,000 0.3 3,333 0.30 4,350

Mb:Fb = sex ratio of breeding males (Mb)tO breeding females (Fb)
Nb = number of breeding individuals needed to maintain an Ne of 500 for stated sex ratio
N/N = proportion of breeding adults contributing genes to the next generation
Ng = minimum number of individuals needed to maintain an Ne of 500 for stated sex ratio
M = average annual adult mortality
MVP = minimum viable population, based on genetic and demographic viability

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