West African Manatee (Trichechus senegalensis) 



The West African manatee is found in the rivers, lagoons, 

 and coastal regions of West Africa from the Senegal River 

 southeast to the Cuanza River in Angola. The species ranges 

 2,000 km up the Niger River into Mali, and a landlocked popu- 

 lation has been reported in tributaries of Lake Chad. The 

 species' abundance is believed to have declined significantly 

 from previous levels, and several local populations are reported 

 to have been completely extirpated. 



The West African manatee is listed as threatened under 

 the U.S. Endangered Species Act. It also is listed on Appendix 

 II of the Convention on International Trade in Endangered 

 Species of Fauna and Flora and as Class A of the African 

 Convention for the Conservation of Nature and Natural Resources. 

 West African manatees are protected by domestic statutes in 

 every country where they are found. 



Several factors have contributed to the reduction in the 

 number of West African manatees. These include subsistence 

 hunting, incidental take by fisheries, mortality resulting 

 from entrapment in dams, and loss of habitat due to develop- 

 ment of wetlands, cutting of mangrove forests, dam construc- 

 tion, and drought. Much of the decline is apparently due to 

 continued subsistence hunting. Although the species is 

 officially protected, enforcement is minimal, and killing and 

 consumption of manatees is openly practiced in many areas. 

 Like other Sirenians, this species probably has a low 

 reproductive rate, which makes it particularly vulnerable to 

 over-exploitation. 



West African manatees live in areas where there is adeguate 

 food, access to fresh water, and calm waters. Construction 

 of dams can pose a particularly serious threat to the avail- 

 ability of these habitat reguirements . For example, damming 

 of rivers can limit access to fresh water for manatees down- 

 stream of dam sites. Above dams, manatees may be unable to 

 reach food during the periodic lowering of reservoir water 

 levels. In addition, construction of dams and barrages blocks 

 reproductive exchange between groups of manatees, creating 

 isolated population units such as has occurred on the Volta 

 and Niger Rivers. A number of other dams have been proposed 

 for major West African rivers by international development 

 agencies and local governments. These structures may pose 

 similar threats to other local populations of manatees. 



A decrease in available food also threatens the continued 

 existence of West African manatee populations. Mangrove is 

 thought to be an important food item for manatees in estuarine 

 areas of West Africa and, in some places, it may be the only 

 food source. Throughout coastal West Africa, mangrove is 



30 



