The longfin dace (Agosia chrysogaster) is a species of leuciscid fish found in southwestern North America. It is the only species of the monotypic genus Agosia. The Gila longfin dace is considered the nominate subspecies, and the Yaqui longfin dace is considered a form.
Etymology
The genus name Agosia is of Native American origin, and the species name chrysogaster is derived from Greek, where chrysós means “gold” and gastḗr means “belly.”[3]
Description
Longfin dace have a bluntly shaped snout and head with a slightly subterminal mouth. The upper jaw contains a small barbel and tends to protrude above the lower jaw.[4] The body is fusiform and covered with small scales. Longfin dace have 70-95 scales along their lateral line, 7-9 anal fin rays, and 9 dorsal fin rays. An adult longfin dace has a maximum total length of 4 inches (100 mm), although it rarely reaches 3.2 inches (81 mm).[4]Age estimation with scales and length-based grouping suggested that most longfin dace live less than two years.[5]
Habitat and range
Longfin dace are native to the deserts of southwestern North America, notably in the American states of Arizona and New Mexico and northern Mexico states of Sinaloa and Sonora.[6] The longfin dace is tolerant to a wide range of water temperature, and is found in low elevation desert streams to mountain brooks.[4] They prefer streams that have sandy or gravel bottoms, typically with overhanging banks or cover to use as protection. During periods of drought, longfin dace may seek refuge in algae and detritus mats.[7]
Longfin dace are omnivorous and opportunistic feeders. They can feed on invertebrates, zooplankton, algae, and detritus.[8]
Reproduction
Longfin dace reach sexual maturity within a year and are able to spawn throughout the year, although most spawning occurs in spring and late summer.[4] Longfin dace will create depressions in the sand to deposit their eggs, which provide cover from predators while the eggs develop and hatch. The eggs and juveniles receive no parental care.
Management
In the United States, longfin dace are considered secure but have been reduced in abundance due to habitat change and introduced fishes.[1][9]
^ abcdMinckley, W.L.; Marsh, P.C, eds. (2009). Inland Fishes of the Greater Southwest: Chronicle of a Vanishing Biota. University of Arizona Press. ISBN9780816527991.
^Page, Lawrence M.; Burr, Brooks M., eds. (2011). Peterson field guide to freshwater fishes of North America north of Mexico (2 ed.). Houghton Mifflin Harcourt. ISBN978-0-547-24206-4.
^Minckley, W.L. and W.E. Barber. 1971. Some aspects of biology of the longfin dace, a cyprinid fish characteristic of streams in the Sonoran Desert. Southwest Naturalist 15(4): 459-564.
^Grimm, N. B. 1988. Feeding dynamics, nitrogen budgets, and ecosystem role of a desert stream omnivore, Agosia chrysogaster (Pisces: Cyprinidae). Environmental Biology of Fishes (21): 143-152.
^"Longfin Dace"(PDF). United States Forest Service. Retrieved 2024-12-28.
