Common Name: Machete, Pacific Tenpounder, Ladyfish.
Scientific Name: Elops affinis
Appearance: Overall silver coloration, with yellowish tinge in eyes and the bases of paired fins; dorsal and anal fins fit into sheaths of scales at base; elongated body; straight lateral line. Machete may achieve lengths of nearly 1.0 m (39.4 in.) at sea but specimens caught from the Colorado River have usually been less than 40.0 cm (15.7 in).
Diet: Fish, Crustaceans.
Habitat and Range: Eastern Pacific from Peru to California, including the Colorado River delta in the Gulf of California (Sea of Cortez); in Arizona, occurs sporadically in the lower Colorado River, possibly following flood events that connect the river to the Gulf. Upstream movement in the Colorado River is limited by dewatering in Mexico and dams in Mexico and Arizona. Machetes were reported in the Salton Sea in California and up river to Imperial Dam until the mid-1940s. The last known record of Machete in Arizona was in 1997; several were caught near Yuma when the Gila River flood flows reached the sea. Little is known about the habitat requirements of the species. Primarily a marine fish found in open seas, coastal waters, bays, tidal streams, lagoons, estuaries and lower reaches of freshwater rivers.
Breeding: Machete broadcast spawn in the open sea. Off-shore spawning sites are unknown but leptocephalus larvae move inshore to develop and grow in brackish water and are common in tidal flats of the Sea of Cortez in early summer. Near transparent leptocephalus larvae, look similar to eels but can be distinguished by a forked tail.
Status: None at this time.
Threats: Lack of connection of Colorado River with the Sea of Cortez, caused by dams, diversions, and overuse of Colorado River water.
Actions: None at this time.
Better Know a Fish! Species Profile can be found at: https://betterknowafish.com/2013/10/27/machete-elops-affinis/
Johnson, D. (2008) Fish of Arizona Field Guide. Adventure Publications, Inc.: pp 162-163.
Minckley, W.L. and P.C. Marsh. 2009. Inland fishes of the greater southwest: chronicle of a vanishing biota. University of Arizona Press, Tucson AZ. Pp 71-72.
Mueller, G.A., and Marsh, P.C., Lost, A Desert River and Its Native Fishes: A Historical Perspective of the Lower Colorado River, Information and Technology Report USGS/BRD/ITR—2002—0010: U.S Government Printing Office, Denver, CO, pp 65.