Status: Ongoing
A series of ponds were constructed adjacent to the river on the U.S. Fish and Wildlife Service Imperial National Wildlife Refuge (INWR). These ponds were built to provide off-channel habitat free of nonnative fishes for the survival and reproduction of bonytail and razorback sucker. Marsh & Associates was contracted to conduct a three-year project to determine the suitability of these ponds for native fishes
Portions of the lower Colorado River between Parker and Laguna dams were surveyed during the period January 2006 to April 2008 as part of a broad program to assess efficacy of the stocking program for razorback sucker Xyrauchen texanus. Our findings document that short-term mortality is high and long-term survival is nil because of predation losses to nonnative fishes and to fish-eating birds.
In March 2010, science journalist Hillary Rosner joined the Marsh & Associates team in the field to learn more about the plight …
Status: Completed
Razorback sucker have been stocked into the lower Colorado River for nearly 30 years, but stocking was accelerated in recent years to meet requirements of a U.S. Fish and Wildlife Service Biological Opinion of lower river operations (USFWS 1997). The purpose of this project was to assess survival of stocked fish by performing an intensive, opportunistic survey that targeted razorback sucker in approximately 282 km of river from Parker Dam downstream to Yuma.
Though functionally extirpated in the wild, bonytail continue to be stocked into the mainstem lower Colorado River. Lake Havasu serves as one of the primary stocking locations and is unique among all stocking sites because bonytail are occasionally recaptured during routine monitoring trips and by sport fish anglers–a feat that is encountered nowhere else.
