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US Fish & Wildlife Service FieldNotes

STOCKTON FWO: Helping Neighbors With Humpback Chub

Region 8, September 28, 2008
Zac Jackson checking for a PIT tag in a humpback chub. (photo: USFWS) 
Zac Jackson checking for a PIT tag in a humpback chub. (photo: USFWS)  - Photo Credit: n/a
Zac Jackson with a bluehead sucker in the Little Colorado River (photo: USFWS)
Zac Jackson with a bluehead sucker in the Little Colorado River (photo: USFWS) - Photo Credit: n/a

by Zac Jackson, Stockton FWO  
In September 2008, Stockton Fish and Wildlife Resource Office fish biologist, Zac Jackson, had the opportunity to assist the Southwest Region's Arizona Fish and Wildlife Conservation Office (AZFRO) with a semi-annual population estimate of adult humpback chub (Gila cypha) in the Little Colorado River.  The mark-recapture study is part of their long-term monitoring effort for this endangered species in the Grand Canyon and used to develop abundance estimates, which help inform long-term management and planning efforts for recovery. 

The work involved fishing 20 hoopnets a day for nine days in the lower nine miles of the Little Colorado River and sampling native fish including humpback chub, bluehead (Catostomus discobolus), and flannelmouth (Catostomus latipinnis) suckers.  Native species captured in the hoopnets are implanted with passive integrated transponder (PIT) tags to individually identify them, a necessity of mark-recapture studies.  Over the 10 days in the canyon, USFWS staff hiked over 40 miles, handled approximately 500 humpback chub, and scared a few rattlesnakes.  The terrain was difficult at times, the mice, scorpions, and cactus were plentiful, and the views and helicopter rides were unbeatable. 

Contact Info: Paul Cadrett, 209-334-2968 x 312, paul_cadrett@fws.gov