Desert Sucker, Catostomus clarkii

Desert Sucker, Catostomus clarkii. Fish caught from the East Verde River, Arizona, June 2020. Length: 8.2 cm (3.2 inches). Catch, photograph and identification courtesy of Ben Cantrell, San Diego, California.

Desert Sucker, Catostomus clarkii. Fish caught from Oak Creek, Sedona, Arizona, October 2022. Length: 13 cm (5.1 inches). Catch, photograph, and identification courtesy of Chris Moore, Peoria, Arizona.

Desert Sucker, Catostomus clarkii. Fish caught from the Lower Salt River, Phoenix, Arizona, June 2021. Length: 17 cm (6.7 inches) each. Catch, photograph and identification courtesy of Luke Ovgard, Klamath Falls, Oregon.

Desert Sucker, Catostomus clarkii. Fish caught from the Lower Salt River, Phoenix, Arizona, January 2017. Length: ca. 25 cm (10 inches) each. Catch, photograph, and identification courtesy of Chris Moore, Peoria, Arizona.

The Desert Sucker, Catostomus clarkii, is a member of the Sucker or Catostomidae Family, also known as the Gila Mountain Sucker and in Mexico as matalote del desierto. Globally, there are twenty-eight species in the genus Catostomus, of which nine are found in the streams, rivers, lakes, and ponds of Mexico’s freshwater systems.

The Desert Sucker is a small compressed, heavy-bodied elongated fish with a depth that is 21% to 25% of standard length. They are bi-colored, olive brown to dark green dorsally, transitioning to silvery-tan or yellowish ventrally. They have cylindrical heads tapering to a blunt face with a thick-lipped large ventral mouth. The scales on the upper half of their body have dark spots which form faint dashed lines. They are sexually dimorphic with males developing a striped pattern with one or two light lateral stripes on a darker background when breeding. Their caudal fin is deeply forked and their dorsal fin has 10 to 11 rays. They have a small head with a subterminal mouth with an enlarged cartilaginous lobe behind the lower lip. They do not have barbels. They have a typical sucker mouth that does not extend past the front edge of the eyes. They are covered with large close-knit silvery scales. They reach a maximum of 33 cm (13 inches) in length and 0.79 kg (1 lbs 12 oz) in weight. As of January 1, 2024, the International Game Fish Association world record stood at 0.79 kg (1 lb 12 oz), with the fish caught in the Lower Salt River, Arizona in October 2013.

The Desert Sucker is a demersal species, found in small to medium freshwater rivers with gravel-rubble bottoms with sandy interfaces in a wide variety of habitats at elevations between 750 m (2,460 feet) and 1,558 m (5,100 feet). Their juveniles are found in riffles; the adults are found in pools during the day and in riffles at night. They cannot survive in reservoirs and lakes. The Desert Sucker has good vision as well as an excellent sense of taste and smell to seek out food. Being bottom-feeding omnivores, they travel and feed in schools. The adult Desert Sucker feed off algae and diatoms that grow on cobbles and boulders and detritus. Juvenile fish feed primarily on small aquatic insects and other invertebrates. They are bioeroders and are considered to be an asset to their ecosystem. Their eggs, fry and juveniles are subject to a 60% to 70% mortality rate due to predation by fish, eagles and herons. They are capable of surviving in a wide range of water temperatures but are intolerant of waters with low dissolved oxygen. Reproduction is oviparous and polygynandrous (promiscuous). Spawning occurs in gravel bars involving one female and two or more males. The female creates a depression in the gravel then deposits eggs which are fertilized by the males. The eggs are buried in the loose gravel and hatch in a few days. They have life spans of ten years.

The Desert Sucker is a straightforward identification that is not easily confused with any other species due to its elongated body and somewhat unique coloration.

The Desert Sucker is very similar to and difficult to distinguish from the Sonora Sucker, Catostomus insignis (full fleshy lips) and the Yaqui Sucker, Catostomus bernardini.

Side by side comparison of the mouth structure of the Desert Sucker, Catostomus clarkii, thinner “D”-shaped lips, and the Sonora Sucker, Catostomus insignis., full fleshy lips. Photographs courtesy of Chris Moore, Peoria, Arizona.

The Desert Sucker is native to the Great Basin and the Colorado River Basin in the southwestern United States in the States of Arizona, Nevada, New Mexico, and Utah and in Northern Sonora, Mexico.  In Mexico they are known to the Rio San Pedro and the Rio Santa Cruz.

From a conservation perspective the Desert Sucker is currently considered to be of Least Concern with total adult populations estimated to be in excess of 10,000 individuals. However, their populations are in decline in many locations and it is anticipated that they will soon be reclassified as Vulnerable. Their populations have been adversely affected by human development which include dewatering of native steams, the construction of dams, fishing pressure, agriculture related pollution, and the introduction of exotic turtles and fishes that compete for food and also prey on the Desert Sucker.