9559

• UCREFRP Catalog Number: 9559
• Author: Martinez, A. M.
• Title: An Evaluation of Nonnative Fish Control Treatments in Ponds along the Colorado and Gunnison Rivers, 1996-2002.
• USFW Year: 2004.
• USFW - Doc Type: 18/19,
• Copyright Material: NO

t
1

1
1

t
w

1

t
11

escapement of fishes from ponds outside the treatment area; 4) detection of reinvasion
of floodplain ponds by nonnative fish species; 5) identification of nonnative fish
movement through screens; 6) determination of reductions in the abundance of
nonnative fishes in existing riverine nursery habitats as a result of nonnative fish control
in floodplain ponds on a river-reach scale; 7) recognition of public concerns and values
and incorporation of public perspectives and issues into the process of reclaiming
ponds; and 8) communication with interested communities concerning the reasons for
pond reclamations and endangered fish recovery.
Approach - Overall, the strategy to remove or prevent the movement of
nonnative fish from floodplain ponds was intended to greatly reduce the number of
chronic sources of centrarchid and other nonnative fish species accessing riverine
habitats, thereby contributing to the recovery of endangered fishes. To accomplish this
strategy control of nonnative fishes was implemented by the Colorado Division of
Wildlife (CDOW) under two categories: (1) reduction of nonnative fish abundance in
riverside ponds and (2) reduction of nonnative fish escapement from ponds. Floodplain
and upland ponds along the Colorado (from Rifle, CO to the Colorado/Utah state line)
and Gunnison (from Austin, CO to the Gunnison River confluence with the Colorado
River) rivers may represent chronic sources of nonnative fish species documented or
presumed to have negative impacts on early life stages of Colorado pikeminnow and
razorback sucker. Reclamation strategies for ponds included 1) removal of existing
nonnative fish species using piscicides and/or draining by pumping; 2) annual water
management resulting in periodic pond drying; 3) installation of escapement prevention
devices; 4) installation of drainage pipes to re-route irrigation water, believed to contain
larval nonnative fish, away from ponds; and 5) installation of black plastic as an
alternative to chemical reclamation to remove excessive aquatic vegetation and
nonnative fish. This report presents the results of these nonnative fish control activities
for 1996 - 2002.
2