267
Fundación Omacha (Bermudez-Romero et al. 2004; Castelblanco-Martinez
2004; Castelblanco-Martínez et al. 2001, 2005). In the central lower Orinoco,
Rivas-Rodríguez et al. (2012) studied the species in Caicara del Orinoco. In adition,
an effort was initiated in 2007 in lower Orinoco, through interviews, sighting
records and identification of feeding areas, between Las Bonitas and Mapire, including Caura river (Rivas-Rodriguez et al. 2012). The authors record the presence of
manatee in 46 localities, expanding the knowledge of the species occurrence in the
Orinoco river originally reported by Mondolfi and Müller (1979) and Correa-Viana
et al. (1990). More recently, Rodulfo (2012) studied manatees in Caño Araguao, in
the Delta of Orinoco, through interviews, indirect evidences of the species presence
(e.g, foraging traces, feces), and sightings. Most records were in distributaries
(caños), followed by the river mouth. Foraging areas were recorded in canõ Araguao,
Río Grande de Araguao, confluence of Rio Grande with caño Anacasi, canõ Janeida,
Canal Sorocobo, Barra de Araguao and Isla Jeocubanoco.
11.2.3 Guyana
Most information published on T. manatus in Guyana is from the 1960s and 1970s
(eg, Bertram 1963; Bertram and Bertram 1963, 1973). The occurrence of the species on the coast seems to be associated to river mouths. Bertram (1963) suggested
that the high water turbidity in the coast probably provided poor feeding grounds to
the species. Most records in the country are from rivers, as Courantyne, Nanniekrek,
Canje, Berbice, Demerara, Abary, Wuini, Barima, Sebai, Kiatuna, Essequibo,
Arapiako, Pomeroon and Akawini. At that time, the species seemed to be more
abundant in the Canje and Abary rivers, mainly in upper reaches, on the wet savannahs. In Abary river, manatees were caught by the Department of Drainage and
Irrigation and released in channels to eat aquatic plants, as a weed control agent.
This practice started in Guyana after Allsop (1960) observed that the ornamental
pools of the Botanic Gardens, in Georgetown, where manatees were kept since the
1880s, were always clear of aquatic plants. In 1916, manatees were used to maintain
sugar-estate canals clear of aquatic plants and in 1952 four manatees were introduced in a canal of a water reservoir of the Georgetown Water and Sewage Works
with the same purpose and were replaced by others through the years (National
Science Research Council 1974). The same procedure was done in other canals
from 1959 to 1962 by Drainage and Irrigation Department, when 80 manatees were
used to control aquatic vegetation. In 1974, a Workshop to discuss “An International
Centre for manatee research” was held in Georgetown. However, the meeting report
discusses mainly the importance of using manatees to control “aquatic weeds” in
the country, and recommends the species exploration for this purpose (National
Science Research Council 1974). In 1991, Haigh published a review on the use of
manatees as a means of biological control of aquatic weeds in Guyana. In the article, the author also proposed guidelines on the use of species.
11 West Indian Manatee Trichechus manatus in South America…
Fundación Omacha (Bermudez-Romero et al. 2004; Castelblanco-Martinez
2004; Castelblanco-Martínez et al. 2001, 2005). In the central lower Orinoco,
Rivas-Rodríguez et al. (2012) studied the species in Caicara del Orinoco. In adition,
an effort was initiated in 2007 in lower Orinoco, through interviews, sighting
records and identification of feeding areas, between Las Bonitas and Mapire, including Caura river (Rivas-Rodriguez et al. 2012). The authors record the presence of
manatee in 46 localities, expanding the knowledge of the species occurrence in the
Orinoco river originally reported by Mondolfi and Müller (1979) and Correa-Viana
et al. (1990). More recently, Rodulfo (2012) studied manatees in Caño Araguao, in
the Delta of Orinoco, through interviews, indirect evidences of the species presence
(e.g, foraging traces, feces), and sightings. Most records were in distributaries
(caños), followed by the river mouth. Foraging areas were recorded in canõ Araguao,
Río Grande de Araguao, confluence of Rio Grande with caño Anacasi, canõ Janeida,
Canal Sorocobo, Barra de Araguao and Isla Jeocubanoco.
11.2.3 Guyana
Most information published on T. manatus in Guyana is from the 1960s and 1970s
(eg, Bertram 1963; Bertram and Bertram 1963, 1973). The occurrence of the species on the coast seems to be associated to river mouths. Bertram (1963) suggested
that the high water turbidity in the coast probably provided poor feeding grounds to
the species. Most records in the country are from rivers, as Courantyne, Nanniekrek,
Canje, Berbice, Demerara, Abary, Wuini, Barima, Sebai, Kiatuna, Essequibo,
Arapiako, Pomeroon and Akawini. At that time, the species seemed to be more
abundant in the Canje and Abary rivers, mainly in upper reaches, on the wet savannahs. In Abary river, manatees were caught by the Department of Drainage and
Irrigation and released in channels to eat aquatic plants, as a weed control agent.
This practice started in Guyana after Allsop (1960) observed that the ornamental
pools of the Botanic Gardens, in Georgetown, where manatees were kept since the
1880s, were always clear of aquatic plants. In 1916, manatees were used to maintain
sugar-estate canals clear of aquatic plants and in 1952 four manatees were introduced in a canal of a water reservoir of the Georgetown Water and Sewage Works
with the same purpose and were replaced by others through the years (National
Science Research Council 1974). The same procedure was done in other canals
from 1959 to 1962 by Drainage and Irrigation Department, when 80 manatees were
used to control aquatic vegetation. In 1974, a Workshop to discuss “An International
Centre for manatee research” was held in Georgetown. However, the meeting report
discusses mainly the importance of using manatees to control “aquatic weeds” in
the country, and recommends the species exploration for this purpose (National
Science Research Council 1974). In 1991, Haigh published a review on the use of
manatees as a means of biological control of aquatic weeds in Guyana. In the article, the author also proposed guidelines on the use of species.
11 West Indian Manatee Trichechus manatus in South America…