i indicated by a dro 
1 reaches of Rfo Polochic have steep gradients, as p 
of 1,000 Bovid ag Tamahu to La Tinta, a distance of about 16 kilometers. from La Tinta 
to Lake Izabal, a distance of more than 80 kilometers, the gradient drops less than 50 
meters. 
ter temperatures above La Tinta are too high for trout during periods of 
ne ware ve These periods may last a few days or weeks. The gradient in 
i season. 
ee ar La Tinta is too great for best results with smallmouth bass 
(Micropterus dolomieu), but it is believed that more fishing will be obtained with this 
species than any other. In the vicinity of la Tinta and downstream to about five kilometers 
tream presents an excellent habitat for this species. From about five 
ee ee ee A i Lake Izabal the stream is sluggish, with gradients of less than 
one-half meter per kilometer. The water in this area varies in depth from one to three or 
more meters. ‘This area is suitable for the largemouth bass (Micropterus salmoides) and the 
crappie (Pomaxis nigro-maculatus ). The bass should provide excellent sport, and the 
crappie should be instrumental in increasing food resources materially. 
io Cahabon, a tribut of the Polochic, arises in the same general area as Rio 
Polochic a. floes westward ail ee einer to Coban, then eastward, ent ering Rfo Polochic 
about 15 kilometers below Panzés. From Tactic to its outlet, it drops about 1,400 meters 
in a course of approximtely 110 kilometers, or an average of 13 meters per kilometer. 
Aecording to a contour map of this area (Sapper, 1899), much of the upper arid lower courses 
of the stream have gradients of less than five meters per kilometer. As the greater portion 
of the stream appears suitable for smallmouth bass, that species is recommended for intro~ 
duction. It is believed also that channel catfish would provide considerable fishing in the 
upper and lower sections. The stream is murky for short periods after rains, and overhanging 
vegetation provides a type of habitat to which the channel catfish is adapted, 
In addition to Rfo Cahabon, the tributaries Rios Neuva (or Tres Aguas) and Semi 
are well suited to the smallmouth bass and channel catfish in their lower reaches, where 
stream gradients are moderate. 
Streams Flowing into the Gulf of México 
Rio Usumacinta Drainage 
That part of the drainage in Guatemala arises in the vicinity of Salamf, Rabinal, 
Cubulco, Santa Cruz Quiché, Momostenango, Huelmetenango, San Mateo, and Ixtatan at altitudes 
of 1,500 to 2,500 meters or more. Rio Negro, the main headwater tributary, arises in the 
vicinity of Santa Cruz Quiché and flows a circuitous route through the valley east of 
Malacatan, eastward to the vicinity of San Cristobal, and then northward:as Rio Chixoy to 
the international boundary of México and Guatemala. It follows the international boundary 
to the western-most point of Departmento El Petén, where it enters the State of Tabasco, 
México, and eventually flows into the Bay of Campeche. The Rio de la Pasion and Rio San 
Pedro, which drain a large part of Peten, also are a part of this system. This drainage was 
examined in only a limited number of places in the highlands. 
The Rio Negro was observed from the air at certain points in the highlands and on 
the ground at Chixoy, Sacapulas, and in the valley east of Malacatan. Also, a few of the 
accessible tributaries were observed. [Due to the very heavy silt load and the fact that the 
stream is murky during a large part of the year, fish foods are not abundant. Some cover is 
provided by rock ledges, but the stream presents a poor environment for fish. It is be- 
lieved that some fishing can be developed with the channel catfish in areas above Sacapulas, 
where the gradient is not unduly steep. From about five kilometers below Sacapulas to 10 
or 20 kilometers below Chixoy, the stream is a turbulent, swiftly flowing stream, too rapid 
to permit development of mch fishing. Below this area, the gradient is more moderate, and 
it is likely that satisfactory fishing can be developed there. : 
The Rio Rabinal and Rio Salam& are mountain streams suitable for developing some 
fishing through the introduction of channel catfish. Some reaches of these streams have 
steep gradients, but in general they are less than five meters per kilometer. Smallmouth 
bass are not recommended for this drainage system, as more investigation in the lower reaches 
106 
