Sonora Sucker, Catostomus insignis

Sonora Sucker, Catostomus insignis. Fish caught from the Lower Salt River, Roosevelt, Arizona, October 2022. Length: 17 cm (6.6 inches). Catch, photograph, and identification courtesy of Chris Moore, Peoria, Arizona.

Sonora Sucker, Catostomus insignis. Fish caught from Oak Creek, Sedona, Arizona, August 2020. Length: 30 cm (12 inches). Catch, photograph and identification courtesy of Luke Ovgard, Klamath Falls, Oregon.

Sonora Sucker, Catostomus insignis. Fish caught from Oak Creek, Sedona, Arizona, October 2016. Length: 46 cm (18 inches). Catch, photograph, and identification courtesy of Chris Moore, Peoria, Arizona.

Sonora Sucker, Catostomus insignis. Fish caught from Oak Creek, Sedona, Arizona, October 2016. Length: 46 cm (18 inches). Catch, photograph and identification courtesy of Eli (obsessiveangling.wordpress.com).

Sonora Sucker, Catostomus insignis. Fish caught from the Lower Salt River, Roosevelt, Arizona, October 2022. Length: 58 cm (23 inches). Weight: 2.8 kg (6 lbs 4 oz). Catch, photograph, and identification courtesy of Chris Moore, Peoria, Arizona. Note: this fish weighed more than any previously documented Sonora Sucker.

The Sonora Sucker, Catostomus insignis, is a member of the Sucker or Catostomidae Family, and is known in Mexico as matalote de Sonora. Globally, there are twenty-six species in the genus Catostomus, of which nine are found in all freshwater systems of Mexico.

The Sonora Sucker has a cylindrical fusiform body that is flattened. They are dark brown dorsally, transitioning to yellow-orange ventrally. Their scales have discrete outlines giving the appearance of spots. Their head is large, has a broad snout, a prominent ventral subterminal mouth with full fleshy lips equipped with pharyngeal teeth. Their dorsal fin has 11 or 12 rays and is square. They are covered with large scales.

The Sonora Sucker is found in a wide variety of habitats, varying from colder trout streams to warm river waters. They are a very sedimentary species that is found primarily in rocky, relatively deep quiet waters. During daylight hours they take cover. They are small in stature reaching a maximum of 80 cm (2 feet 6 inches) in length and 2.8 kg (6 lbs 4 oz) in weight as documented by the fish photographed above. They have a highly developed sense of hearing, smell, and taste and vary their diet based on availability – they are carnivores that consume aquatic insect larvae but are also omnivorous bottom feeders consuming algae, crustaceans, micro-invertebrates, plant material and protozoans. They are heavily preyed upon by the Channel Catfish, Ictalurus punctatus, Flathead Catfish, Pylodictis olivaris and Smallmouth Bass, Micropterus dolomieu. They rely on counter-shading patterns to avoid predation. Reproduction is oviparous and polygynandrous (promiscuous). Spawning occurs in the spring in small streams or within riffles of larger streams. It occurs in gravel bars involving one female and two or more males. The adhesive eggs are buried in loose gravels where they hatch in a few days. The Sonora Sucker is poorly studied with very limited information available about their lifestyle and behavioral patterns, including specific details on age, growth, longevity, movement patterns, diet, habitat use, and reproduction.

The Sonora Sucker is very similar to and difficult to distinguish from the Desert Sucker, Catostomus clarkii (thinner “D”-shaped 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 Sonora Sucker is native to the Southwest United States and Northern Mexico. In Mexico they are found in the Pacific drainage of the Santa Cruz and San Pedro Rivers within the Gila Basin in northern portions of the state of Sonora, at elevations between 300 m (1,000 feet) and 2,500 m (8,200 feet).

From a conservation perspective the Sonora Sucker is currently considered to be of Least Concern with stable, widely distributed populations, however their populations have declined significantly in the southern part of its range and are very threatened. Current populations are estimated to be in excess of 10,000 individuals. Their populations and long-term viability are currently threatened by dam construction, as they are intolerant of lakes, habitat degradation including sedimentation, changes in water flow as they are prone to die offs with low water flow, and the addition of herbicides and pesticides to their environment. They are prone to hybridization with the Desert Sucker, Castostomus clarkii, and to strong competition and predation by the introduction of nonnative fishes. Their long-term survival has drawn the attention of several government organizations.