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

Bonytail - 3

Gila River Subbasin and Lower Colorado River
1. Two populations, each with a minimum estimated number of 3,500 adults for a
period of 5 years, such that:
a. the lower 95% confidence interval of the estimated population of adults
exceeds 3,500,
b. a trend in adult population point estimates for the same 5-year period that
does not decline significantly, and
c. a proportion of age 3 fish for each year that is not significantly higher than
30% or lower than 20% of the adult population for the same 5-year period.
2. Procure habitats necessary to recover the bonytail.
3. Implement nonnative fish control, as needed, to recover the bonytail.

Delisting Criteria
Delisting of bonytail will be considered when the following criteria are met:

Lake Mohave
1. Maintain at least 50,000 adults for genetic viability for at least 15 years as wild
genetic refugia,

Green River Subbasin
1. A minimum estimated population of 4,500 adults for a period of 15 years, such
that:
a. the lower 95% confidence interval of the estimated population of adults
exceeds 4,500,
b. a trend in adult population point estimates for the same 15-year period that
does not decline significantly, and
c. a proportion of age 3 fish that is not significantly higher than 30% or lower
than 20% of the adult population for the same 15-year period.
2. Provide legal protection, assurances, and/or agreements for flows necessary to
recover the bonytail.
3. Regulate nonnative fish releases in the main river, flood plain, and tributaries
through agreements.
4. Implement nonnative fish control, as needed, to recover the bonytail.

Upper Colorado River Subbasin
1. A minimum estimated population of 4,500 adults for a period of 15 years, such
that:
a. the lower 95% confidence interval of the estimated population of adults
exceeds 4,500,
b. a trend in adult population point estimates for the same 15 year period that
does not decline significantly, and
c. a proportion of age 3 fish that is not significantly higher than 30% or lower
than 20% of the adult population for the same 15-year period.
2. Provide legal protection, assurances, and/or agreements for flows necessary to

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