Costalegre Mexico
 

 At the invitation of the Fundaci¢n Ecol¢gica de Cuixmala, I made a short visit to the Chamela-Cuixmala Biosphere Reserve to review and make recommendations concerning the current situation of a population of American crocodiles. The Chamela reserve has been protected since 1971 and has long been a center of ecological research at the Universidad Nacional Autonoma de Mexico (UNAM). In 1987, lands adjacent to the Chamela reserve were set up as a private reserve by the English-French billionaire Sir James Goldsmith. This region, referred to as Cuixmala, was combined with the Chamela reserve in 1993 to create the Chamela Cuixmala Biosphere Reserve. Most of the reserve is covered by a low-stature dry forest, however, one section adjacent to the Goldsmith family homes contains coastal habitats including mangrove lagoons and canals that harbor a significant population of American crocodiles. The Cuixmala reserve and adjacent areas contains three distinct areas with crocodiles: the Careyes area of natural mangrove canals and lagoons, the Cuixmala sub-region with canals and highly altered habitats (man-made lagoons, road construction and water-level control using floodgates), and the lower reaches of the Cuitzmala River, which is located just outside the reserve. In 1987, initial surveys of crocodiles in the reserve were conducted by Gustavo Casas Andreu and co-workers, and revealed the presence of a good population (10 nests/yr.) of crocodiles. Subsequent surveys were carried out by Marco Lazcano in 1989, and were the subject of a thesis project by Luis Octavio in 1993. Crocodile work has continued in recent years under Andres Garcia and Marciano Valtierra of the Fundaci¢n Ecol¢gica de Cuixmala (FEC). Marciano is currently the only full-time biologist employed by FEC and among his responsibilities is the monitoring of the crocodile population. Since the late 1980s the number of nests in the reserve has grown from 10 to nearly 30 per year. The total crocodile population in the area is probably 500-600 and it is amongst the largest known for Mexico. I spent four days with Marciano in the reserve, visiting the different crocodile habitats and conducting nocturnal spotlight counts in different parts of the reserve.

During the last year, the first reports of a crocodile attack (non-fatal) on a fisherman (April) and on cattle (3 in December, one died). While the attacks on cattle have not been confirmed as having been due to crocodiles, strong suspicions have been awakened in the minds of people in the neighboring village of Zapata and the Cuixmala administration. Potential threats to people and cattle are greatest in the lower Rio Cuitzmala, which is located just outside the reserve. Fishing pressure in the river is greatest during periods of low water. While some fishing is done using cast nets or hook and line, other fishermen work by swimming in the river with spearguns, or by hand-grabbing freshwater prawns (langostinos) living in cavities along the riverbank. The fisherman who was attacked was spearfishing in the river with a mask and fins, and had a bag with several kilos of fish with him. He was bitten on the foot, and after a struggle with the crocodile managed to escape. When we censused it, the river contained a moderately high density of crocodiles (28 crocodiles seen over 2 km), which included a few adults. Clearly fishing by swimming and diving in the river risks the potential attack of crocodiles confused by the smell of fish and the sudden movements of the fishermen. From the viewpoint of logistics, this is one of the best populations of American crocodiles that I know of for study. The reserve is criss-crossed by roads, which provide the principal nesting habitat for crocodiles in the Cuixmala section of the reserve. Most areas where crocodiles are found are readily accessible by small boat. The crocodiles are concentrated in a relatively small area (ca. 100 ha). Furthermore, as the reserve is equally divided among natural mangrove habitat and human-altered areas (construction of roads, lagoons), it offers and excellent opportunity to examine how American crocodiles adapt to disturbed habitats. -- John Thorbjarnarson, 2300 Southern Blvd., Wildlife Conservation Society, Bronx, NY 10460.