In 1946, the surface and bottom water temperatures were 29 degrees Centigrade; 
and in 1947, 29.5 degrees. Air temperatures at the time of the tests were from 29 to 30 
degrees. 
A Secchi disk (20 centimeters in diameter) disappeared at 2.86 meters at 1:30 p.m., 
April 5, 1946, and at 1.8 meters at 10:00 a.m., April 26, 1947. Both readings were made in 
the lower end of the lake. .The lower transparency in 1947 was due, apparently, to increased 
phytoplankton. 
Approximately 37 genera and 50 species of fishes were collected from Lago Izabal, 
It is probable that many of the species are new, for no extensive collection of fishes had 
been made there prior to this study. A list of the genera of fishes collected in Lago 
Izabal is as follows: 
Carcharhinus: Pristis; Tarpon; Anchoa; Anchovia; Hyphessobrycon; Astyanax; Brycons; 
Caleichthys; Arius; Bagre; Rhamdia; Strongylura; Hyporhamphus; Belonesox; Gambusia; 
Mollienisia; Phallichythys; Centropomis; Thyrinops; Mugil; Bucinostoms; Bugerres; 
Oligoplites; Caranx; Micropogon; Archosargus; Cichlasoma; Herichthys; Qostethus ; Pseudo- 
phallus; Coliomorus; Lophogobius; Gobioides; Garmannia; Synbranchus and Trinectes. 
El Golfete lies about 10 kilometers below Lago Izabal. The two lakes are comected 
by a channel which is from one to two kilometers wide, and four to eleven meters deep. At 
San Felipe, the outlet of Lago Izabal, the channel is only about 50 meters wide. El Golfete 
is approximately 15 kilometers long, three to five wide, and has a total area of about 6,000 
hectares, It is surrounded by dense jungle, and the water extends into mangrove swamps. 
For the most part, the water is from four to five meters deep, and the bottom consists of 
soft mud (Map No. 1). 
At 10:30 a.m., April 11, 1946, water samples showed 4.8 parts per million of oxygen 
at 1 meter, and 5.0 at 5 meters (bottom). The carbon dioxide content was 2 parts per million 
at 1 meter, and 7 and 5 meters (bottom). Surface and bottom water temperatures (5 meters) 
were 29 degrees Centrigrade. ~Methyl orange alkalinity was 35 parts per million. The Secchi 
disk (20 centimeters in diameter) disappeared at 1.8 meters. No fish collections were made 
in El Golfete. 
Rfo Dulce drains El Golfete, and flows into the Bahia de Amatique at Livingston, 
a distance of about 13 kilometers. The gradient from El Golfete to the mouth of the Rio 
Dulce is about 0.7 meters per kilometer, a total of less than 10 meters. The depth varies 
from 3 to 40 meters and the width from 15 to 45 meters. Turing the dry season, the current 
is imperceptinle to the eye, Strong winds usually blow upstream in the afternoons, and may 
carry salt water to the lower end of El Golfete. The water of Rio Dulce may vary from fresh 
to brackish according to the strength of the winds and seasonal rains which affect the volume. 
The stream has many right angle turns, and has cut deep into limestone formations P 
forming cliffs 15 to 75 meters or more in height. The white cliffs are covered in most 
Places with tropical vegetation, and many of the walls are cavernous. The boat journey from 
Livingston to El Golfete is extremely scenic and delightful. The stream is also popular for 
its sabalo (Tarpon) and robalo (Centropoms) fishing. 
The Rio Dulce, El Golfete, and Ri® Polochic areas contribute to the economy of 
Guatemala principally as a waterway over which commodities transported between the railroad 
terminus at Panz6s and Livingston and Puerto Barrios. Any recommendations for the develop- 
ment of the fisheries should consider primarily the economic improvements that may be made 
locally or for the entire Republic. At the present time these waters are utilized little 
for commercial fishing. Only one small commercial seine was found on the lake. Although 
fishing there probably can be profitable, it would appear that considerably more profits 
can be made in salt water at Livingston and the Surrounding areas. From 10 hauls made at 
random with a seine 183 meters in length and 4.8 meters in height, approximately 186 kilo- 
grams of fish were taken from Lake Izabal., This is an average of 18.3 kilograms per haul. 
Other hauls made in areas chosen by experienced fishermen netted from 27 to 73 kilograms 
per seine haul, These catches consisted of many inferior food fishes such as the catfishes 
(bagre), mojarras (Cichlasoma), machaca (Brycon), and sabalo (Tarpon), as well as the more 
desirable robalo (Centropoms). Except in Jamary when robalos are mumerous in Lago Izabal 
