Speckled Dace, Rhinichthys osculus
Speckled Dace, Rhinichthys osculus. Fish caught from a remote location of New Mexico, August 2020. Length: 12 cm (4.9 inches). Catch, photograph and identification courtesy of Luke Ovgard, Klamath Falls, Oregon.
Speckled Dace, Rhinichthys osculus. Fish caught from a coastal river in Brookings, Oregon, September 2021. Length: 13 cm (5.0 inches). Catch, photograph and identification courtesy of Luke Ovgard, Klamath Falls, Oregon.
Speckled Dace, Rhinichthys osculus. Fish caught from the Spring Creek, Payson, Arizona, August 2020. Length: 13 cm (5.1 inches). Catch, photograph and identification courtesy of Luke Ovgard, Klamath Falls, Oregon.
Speckled Dace, Rhinichthys osculus. Fish caught from the Silver Creek, Show Low, Arizona, June 2020. Length: 13 cm (5.1 inches). Catch, photograph, and identification courtesy of Chris Moore, Peoria, Arizona.
Speckled Dace, Rhinichthys osculus. Fish caught within the Santa Fe National Forest, New Mexico, July 2017. Length: 13 cm (5.1 inches). Catch, photograph, and identification courtesy of Ben Cantrell, San Diego, California.
Speckled Dace, Rhinichthys osculus. Fish caught within the Santa Fe National Forest, New Mexico, July 2017. Length: 13 cm (5.1 inches). Catch, photograph and identification courtesy of Eli (obsessiveangling.wordpress.com).
The Speckled Dace, Rhinichthys osculus, is a member of the Carp and Minnows or Cyprinidae Family, that are also known as the Dusky Dace, the Pacific Dace, the Spring Dace and the Western Dace, and in Mexico as carpita pinta. There are currently fifteen recognized subspecies of Rhinichthys osculus, that vary significantly in morphology and range. Globally, there are nine species in the Rhinichthys Genus, of which three are found in all freshwater systems of Mexico.
The Speckled Dace has a cylindrical elongated torpedo-shaped body that is deepest at the front edge of the dorsal fin. They are an overall gray-brown color and covered with scattered dark flecks that are more prominent above the mid-line of the sides. They have a faint lateral band. Ventrally they are yellowish or creamy white. The bases of their fins turn red and the males get red snouts and lips when breeding. Their head is bluntly triangular, with a pointed snout with a small hump present behind the head, and a terminal mouth that is “sucker like”, equipped with pharyngeal teeth. The lower jaw has fleshy lips and a well developed maxillary barbel. Their anal fin has 6 or 7 rays; their dorsal fin has 8 or 9 rays; their pectoral fins have 12 to 14 rays, and their pelvic fins have 7 or 8 rays. Their lateral line is incomplete. They are covered with small randomly placed scales.
The Speckled Dace is a demersal shallow water freshwater fish that is found in a wide variety of habitats ranging from cold swift-flowing mountain headwaters to warm intermittent desert streams and springs in clear, well-oxygenated waters with rocky riffles, runs and pools from low elevations to high mountain brooks. They also thrive in areas with cover, vegetation and woody debris. They are most active at night. They can survive in waters that are between 10oC (50oF) and 30oC (86oF). They are intolerant of reduced oxygen levels, habitat alternation, degradation of water flow, and sedimentation in water. They are small in stature, reaching a maximum of 11 cm (4.3 inches) in length with females growing more rapidly than males. Juveniles are found in shallow waters; adults are found in deep channel habitats. They are omnivorous bottom feeders that consume algae, aquatic insects, fish eggs, plant material and zooplankton. They are heavily preyed upon by a wide variety of introduced forage fishes such as Brown Trout, Salmo trutta, Green Sunfish, Lepomis cyanellus, and Largemouth Bass, Micropterus salmoides and competition from Channel Catfish, Ictalurus punctatus and the Western Mosquitofish, Gambusia affinis. They rely on counter-shading patterns to avoid predation. Reproduction is oviparous and polygynandrous (promiscuous) in large groups. 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. Each female will release between 200 and 500 eggs which are adhesive and attach to rocks. The larvae hatch in six days and remain in their gravel areas for seven or eight days. They have lifespans of six years.
The Speckled Dace are native to the entire west coast of southern Canada and the United States and are the most ubiquitous freshwater fish in the western states. They have been widely introduced throughout their range both intentionally and accidentally, primarily to provide a forage fish for Bass and Trout. In Mexico they are found in the Pacific drainage in the northern portions of the state of Sonora.
From a conservation perspective the Speckled Dace is currently considered to be of Least Concern with stable, widely distributed populations. They are widely used as a bait fish in the western United States. Their populations and long-term viability are currently threatened by habitat degradation, including sedimentation, changes in water flow as they are prone to die offs with low water flow, destruction of stream and riparian habitat by livestock, and the addition of herbicides and pesticides to their environment. They are known to hybridize with the Least Chub, Iotichthys phlegethontis.