Native trout of the Baja Pensinsula Trout of the Acaponeta watershed Trout of the Rio Baluarte watershed Trout of the Rio del Presidio Trout of the Rio Piaxtla and tributaries Trout of the Rio San Lorenzo watershed Oncorhynchus chrysogaster Trout of the Rio Mayo watershed Trout of the Rio Yaqui watershed Photos from the Rio Piaxtla watershed

Oncorhynchus sp.

HomeTruchas MexicanasRio ConchosMapHistory

Trout of the Rio Piaxtla (pronounced "pee-ást-lah") eluded scientists for many years, the watershed having been overlooked by Needham and Gard and others.  In the year 2000,  ichthyologist Rogelio Otto collected trout from a Piaxtla tributary -- Rio Verde -- near La Bufa.  Since, a number of high-mountain northern tributaries have been found to contain native trout.  A series of spectacular waterfalls on the mainstem Piaxtla may have restricted upstream dispersal of trout, and could be responsible for their absence in some of the headwater streams of the Rio Piaxtla.   However, residents of Doce de Mayo (off the main road to San Miguel de Cruces) have told us that trout were in their arroyos years ago when water conditions were more suitable.

Piaxtla trout are similar to the trout of the Rio San Lorenzo (just to the north), but are typically more colorful and tend to be more heavily spotted.  The Piaxtla trout have more parr marks than any other North American trout, with as many as 18 oval marks intersecting the lateral line, and have an unusual profusion of dark gray auxiliary parr marks (NOT black spots) below the lateral band.  Larger specimens (7 inches is a "large" one)  are also peculiarly spotted on the lower head, jaw, and opercle, and the dorsal fins are more broadly tipped with opaque white than those of other Mexican trout.  The Piaxtla/San Lorenzo trout are unique, and may constitute their own species complex.  To date we know of no hatchery trout in the northern Piaxtla watershed, but some intrabasin transfers of trout have been conducted by local residents.  Particularly worrisome is the suggestion of a rainbow trout grow-out facility near Puentecillas, which would most assuredly lead to introgression of the beautiful native trout of this area.