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Contact: Brian Healy, 928-638-7453
Contact: Maureen Oltrogge, 928-638-7779
Grand Canyon, Ariz. - On June 23, 2010, the National Park Service, in cooperation with the Bureau of Reclamation, the U.S. Fish and Wildlife Service, and the Arizona Game and Fish Department will translocate an additional 300 juvenile humpback chub to Shinumo Creek in Grand Canyon National Park.
The multi-year translocation experiment to Shinumo Creek began in 2009 with the successful translocation of 300 juvenile humpback chub. The main purposes of this conservation experiment are to fulfill a commitment of a U.S. Fish and Wildlife Service biological opinion and to assess the feasibility of establishing an additional spawning aggregation of this endangered fish in a Grand Canyon tributary. This second translocation will augment the number of humpback chub that remain in Shinumo Creek following the 2009 translocation. It also will assist in determining whether there is an opportunity for rearing humpback chub in a tributary other than the Little Colorado River, the only tributary in which the fish presently reproduces and reaches adulthood. Future humpback chub releases into Shinumo Creek will depend on monitoring results, which will allow researchers to gather additional information on the effectiveness of using translocation as a conservation tool for this Colorado River native.
The humpback chub (Gila cypha) is endemic to the Colorado River basin. The species is well adapted to natural conditions of the Colorado River - high turbidity, high water velocities and seasonally variable flows and temperatures. Humpback chub are endangered because of human-caused changes to the Colorado River ecosystem. Today, the largest remaining population is found near the confluence of the Colorado River and Little Colorado River in Grand Canyon.
Shinumo Creek, a small, clear-water tributary joining the Colorado River at approximately River Mile 109, is believed to have suitable habitat for humpback chub based on studies of water quality, water temperature, and available food. A barrier falls is found just above its confluence with the Colorado River, which prevents non-native predatory fish inhabiting the mainstem river from moving into Shinumo Creek.
The juvenile humpback chub that will be released in Shinumo Creek were captured in 2009 near the mouth of the Little Colorado River. The fish were treated to remove any parasites that may be present, kept overwinter, and then implanted with passive-integrated-transponder (PIT tags) to uniquely identify individual fish at the U.S. Fish and Wildlife Service Dexter National Fish Hatchery and Technology Center, in New Mexico.
Data collected to date indicate that the 2009 translocation has been successful. The young fish were observed actively feeding and behaving normally almost immediately after being released.
Available data indicate that most of the humpback chub released last year remained in Shinumo Creek through mid-December. The use of PIT tags and the stream gages that were installed in the creek last year allowed scientists to evaluate the success of the translocation. The fish that will be released this year will also contain PIT tags so that the growth, survival, and movements of the translocated fish can be monitored.
Monitoring in June, combined with data from the PIT tag antenna, will allow biologists to assess the survival and growth of humpback chub that were released in 2009. A second monitoring trip is planned for September. One variable that will be analyzed is whether humpback chub will be able to withstand monsoonal flooding as a result of heavy rains or snowmelt. Stream gage data showed that Shinumo Creek didn’t flood last year after the initial translocation.
The initial translocation efforts are considered experimental; however depending on the success of the Shinumo translocation, future translocation efforts may contribute towards NPS restoration goals for native fish communities in Grand Canyon. Translocations to tributaries may result in improved survival for juvenile humpback chub by providing rearing habitat with suitable temperatures and abundant food to allow for better growth than in the colder Colorado River. Larger fish may have a greater chance for survival if they leave Shinumo Creek and enter the Colorado River, which may lead to larger chub aggregations there.
Grand Canyon National Park Superintendent Steve Martin said, “I’m excited about the upcoming humpback chub translocation to Shinumo Creek and our efforts to protect Grand Canyon’s native species. If the Shinumo Creek translocation is ultimately successful, this conservation tool may become an important part of the recovery efforts for this Colorado River native fish.”
There are no closures at Shinumo Creek because of this translocation experiment. Anglers in Shinumo Creek should become familiar with the identifying characteristics of humpback chub to avoid any accidental capture of the translocated chub. Young humpback chub are silver, have small eyes and large fins, but have not yet developed the pronounced hump behind their head. If any humpback chub are incidentally caught, they must be immediately released unharmed.
For more information, please contact Brian Healy, Fisheries Biologist at 928-638-7453 or Maureen Oltrogge, Public Affairs Officer, at 928-638-7779. Additional information on the Shinumo Creek humpback chub translocation is available online at https://www.nps.gov/grca/naturescience/shinumotransloc.htm.