Zuni bluehead sucker (Catostomus discobolus yarrowi) | ESA status: endangered

Zuni bluehead sucker facts

Also known as the Zuni mountain sucker, the Zuni bluehead sucker is a small, slender fish with a bluish head, silvery tan to dark green back, and yellowish to silvery white sides and abdomen. The fish grows to between 3.5 and eight inches. Males exhibit a bright red band running laterally along each side during the spawning season. The fish uses stream reaches with clean, perennial water flowing over hard substrate, such as bedrock. It feeds primarily on algae it scrapes from rocks, rubble, and gravel on the streambed. It appears to avoid silt-laden habitat, such as beaver ponds.

Zuni bluehead sucker habitat

The Zuni bluehead sucker was once common in the Little Colorado and Zuni River drainages. Scientists postulate that this subspecies may be a prehistoric hybrid of the Rio Grande sucker (Catostomus plebeius) and bluehead sucker (Catostomus discobolus). Now genetic isolation may be affecting the fish.

The current range of the Zuni bluehead sucker has been reduced to less than 10 percent of its historic distribution. The fish is now restricted to three semi-isolated populations (totaling just three stream miles) in the upper Rio Nutria drainage in west-central New Mexico, and scattered areas along 27 miles of the Kinlichee (a.k.a. “Kin Li Chee”) watershed in Arizona.

What are the threats to the Zuni bluehead sucker?

The fish faces a host of threats, including habitat modification and stream siltation caused by logging, livestock grazing, road construction, residential development and reservoirs; reduced or discontinuous stream flow from water withdrawal for irrigation; application of piscicides (fish toxicants); and competition with and predation by exotic fishes and crayfish.

The U.S. Fish and Wildlife Service first designated the Zuni bluehead sucker as a candidate for listing in 1985, then dropped the subspecies when it reorganized the candidate list in 1996, only to make the fish a candidate again in 2001. It is now listed as “endangered” with critical habitat.