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Fauna of Los Tuxtlas
Fishes
Fishes
Lago Catemaco is a volcanic crater lake located on the Atlantic
coastal plain of Mexico [17o 24' N, 95o 04' W] 176 kilometers to the
south of the city of Veracruz. The lake lies at an altitude of 335
m above sea level in a basin eleven kilometers long by eight
kilometers wide. A number of small streams flow down the interior
face of the crater into the lake, which has an outlet to the
northeast into a river known locally as the Rio Grande.
Twelve kilometers downstream of the outflow, a 45 meter high waterfall,
the Salto de Eyiplanta, effectively isolates the lake from the
lower reaches of the Rio Papaloapam system. The climate along the
coastal plain in the State of Veracruz is tropical, with heavy but
seasonal precipitation. The lake is extremely turbid due to
suspended particles of basaltic dust. Its water is alkaline [pH
7.8 - 8.0] and moderately hard, with CO3-- hardness varying
seasonally between 3o and 5o DH. (Artigas Azas, 1992; Contreras and
Rivera-Teilery, 1985; Mayland, 1984).
The ichthyofauna of Lago Catemaco comprises 16 species, 44% of them
endemic. The most important families are the Cichlidae[6], the
Poeciliidae[3] and the Characidae[2] (Contreras and Rivera-Teilery,
1985; Mayland, 1984; Miller, 1975; Rosen, 1960 ). The lake's
endemic cichlid, an undescribed sister species of the widespread
fluviatile _Theraps fenestratus_, is characterized by color
polymorphism. In addition to the preponderant normally pigmented
individuals, both orange-pink and white oligomelanic morphs have
been reported (Artigas Azas, 1992; Hernandez-Rolon, 1984).
Five exotic species, among them _Oreochromis aureus_, the blue
tilapia, are established in the lake basin (Artigas Azas, 1992;
Contreras and Escalante, 1984). However, the principal threat to
this ecosystem is anthropogenic eutrophication. The interior of
the crater is heavily settled, the city of Catemaco on the northern
shore of the lake boasting a population of 250,000. The lake is
a popular vacation spot and the focus of ongoing real estate
development (Artigas Azas, 1992).
The endemic Catemaco _Theraps_ species and the non-endemic cichlids
found in the lake are pond-bred in Florida for the ornamental fish
trade and thus readily available through commercial channels in
North America, Europe and Japan. One of the three endemic
poeciliid species, _Xiphophorus milleri_, the Catemaco platyfish,
is being maintained on a long-term basis by the Aquarium for
Wildlife Conservation in New York. The remaining two species can
be obtained through specialty hobbyist groups such as The American
Livebearer Association, The Livebearer Information Service in Great
Britain and the Deutsche Gesselschaft fur Lebendegebaerende
Zahnkarpfen.
http://www.peter.unmack.net/acn/as/3/vol3no2.txt
coastal plain of Mexico [17o 24' N, 95o 04' W] 176 kilometers to the
south of the city of Veracruz. The lake lies at an altitude of 335
m above sea level in a basin eleven kilometers long by eight
kilometers wide. A number of small streams flow down the interior
face of the crater into the lake, which has an outlet to the
northeast into a river known locally as the Rio Grande.
Twelve kilometers downstream of the outflow, a 45 meter high waterfall,
the Salto de Eyiplanta, effectively isolates the lake from the
lower reaches of the Rio Papaloapam system. The climate along the
coastal plain in the State of Veracruz is tropical, with heavy but
seasonal precipitation. The lake is extremely turbid due to
suspended particles of basaltic dust. Its water is alkaline [pH
7.8 - 8.0] and moderately hard, with CO3-- hardness varying
seasonally between 3o and 5o DH. (Artigas Azas, 1992; Contreras and
Rivera-Teilery, 1985; Mayland, 1984).
The ichthyofauna of Lago Catemaco comprises 16 species, 44% of them
endemic. The most important families are the Cichlidae[6], the
Poeciliidae[3] and the Characidae[2] (Contreras and Rivera-Teilery,
1985; Mayland, 1984; Miller, 1975; Rosen, 1960 ). The lake's
endemic cichlid, an undescribed sister species of the widespread
fluviatile _Theraps fenestratus_, is characterized by color
polymorphism. In addition to the preponderant normally pigmented
individuals, both orange-pink and white oligomelanic morphs have
been reported (Artigas Azas, 1992; Hernandez-Rolon, 1984).
Five exotic species, among them _Oreochromis aureus_, the blue
tilapia, are established in the lake basin (Artigas Azas, 1992;
Contreras and Escalante, 1984). However, the principal threat to
this ecosystem is anthropogenic eutrophication. The interior of
the crater is heavily settled, the city of Catemaco on the northern
shore of the lake boasting a population of 250,000. The lake is
a popular vacation spot and the focus of ongoing real estate
development (Artigas Azas, 1992).
The endemic Catemaco _Theraps_ species and the non-endemic cichlids
found in the lake are pond-bred in Florida for the ornamental fish
trade and thus readily available through commercial channels in
North America, Europe and Japan. One of the three endemic
poeciliid species, _Xiphophorus milleri_, the Catemaco platyfish,
is being maintained on a long-term basis by the Aquarium for
Wildlife Conservation in New York. The remaining two species can
be obtained through specialty hobbyist groups such as The American
Livebearer Association, The Livebearer Information Service in Great
Britain and the Deutsche Gesselschaft fur Lebendegebaerende
Zahnkarpfen.
http://www.peter.unmack.net/acn/as/3/vol3no2.txt
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