Prochilodontidae - Ichthyoelephas humeralis (Gunther, 1860)

SOURCE FOR OCCURRENCE IN ECUADOR: This species is common in the Guayas River drainage. There are many references for its occurrence in the area (e.g., Eigenmann, 1922; Ovchynnyk, 1971; Barnhill et al., 1974; Gery, 1977; Glodek, 1978; Cadena, 1981; Barriga, 1991; Florencio, 1993; Laaz et al., 2009; Revelo, 2010; Laaz & Torres, 2010).
ORIGINAL DESCRIPTION: Günther, A. 1860. Second list of cold-blooded vertebrata collected by Mr. Fraser in the Andes of western Ecuador. Proceedings of the General Meetings for Scientific Business of the Zoological Society of London 1859 (pt 3):402-420.
TAXONOMIC STATUS: Valid (Eschmeyer and Fricke, 2017).
RANGE ECUADOR: Guayas River drainage. Castro and Vari (2003) also list it as occurring in the Santiago River drainage in Esmeraldas province, northwestern Ecuador (close to the border with Colombia), and Bohlke (1958) presents measures of four specimens presumably collected near Borbon in this drainage (USNM-164031 and ANSP-75965), but there are no recent confirmed records of this species in rivers of Esmeraldas province. It is unclear whether the species naturally occurred (or still occurs) in rivers of Esmeraldas province or whether it may have been introduced there for aquaculture purposes since it is one of the most valued freshwater food fishes in the region.
RANGE OUTSIDE OF ECUADOR: May occur in Pacific drainages of Northwestern Peru (Ortega et al., 2011).
MAXIMUM SIZE: 38.5 cm (Cadena, 1981).
DISTINGUISHING FEATURES: As the only representative of the family Prochilodontidae in western Ecuador, Ichthyoelephas humeralis is distinguished from other species occurring in the region by their extremely enlarged fleshy lips that form an oral disk upon protraction. They also have a subterminal mouth, protractible jaws, a large snout that fits two times in its head length (Glodek, 1978).
ECOLOGY: Ichthyoelephas humeralis, known in Ecuador as the “bocachico” or "lampon", is a large, ecologically important fish that feeds on detritus and algae, the latter of which is scraped off submerged wood and rocks (Barnhill les et al., 1974). Icthyoelephas humeralis engages in mass migrations upstream at the start of the rainy season in December and January (Revelo and Laaz, 2012). Barnhill Les et al. (1974) presented egg counts of between 75,881-140,536 eggs for three females ranging in size between 27 and 28.4 cm total length. Eggs were listed as approximately 1 mm in diameter. As a consequence of feeding low in the food web and their large population sizes, prochilodontids like I. humeralis often play important roles in the energy dynamics of the aquatic ecosystems that they inhabit (Castro and Vari., 2003).
ECONOMIC IMPORTANCE: This is one of the most important food fishes for people in rural parts of Los Rios province (Revelo, 2010).
CONSERVATION STATUS: NA, although the species is heavily exploited as a food species and is extremely vulnerable to fishing pressures because of its migratory habits. There is significant anecdotal evidence from fishermen that it has declined substantially in abundance in the last few decades. There is an urgent need for a comprehensive study on the current state of this species in the Guayas River drainage.
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Created: October 29, 2010
Last Updated: August 19, 2017
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