RECENT SURVEY ON THE DISTRIBUTION
OF THE AFRICAN MANATEE
MASAHARU NISHIWAKI, MASASHI YAMAGUCHI,SHIGEMITSU SHOKITA
Faculty of Science, University of the Ryukyus, Okinawa

SENZO UCHIDA
Okinawa Ocean EXPO Memorial Park Aquarium, Okinawa

AND

TERUO KATAOKA
Toba Aquarium, Mie

ABSTRACTThe survey was made in travelling west African countries in 1980 and 1981
mainly on the distribution of African manatee, Trichechus senegalensis.
It was confirmed that the manatees were inhabiting the Senegal Riversystem.
Manatees were distributed sparsely between Guinea-Bissau and Liberia
through Sierra Leone and abundantly from Ivory Coast to Nigeria extending
to Mali. Considerable numbers were in Cameroon and Gabon. The mostabundant area was in the Niger River and its tributaries with connected swamps.
According to the literature, the southern limit of the distribution is in
Angola, but we were not able to enter the country to confirm it.
INTRODUCTION

A fundamental thing for the study of an animal distribution is to determine whether only one or more than one species are present. In an attempt to answer the
species question, the senior author examined the sirenia collection at the British
Museum (Natural History) in 1973. Also, through the kind cooperation of Dr.
Chales Roux (Museum Nationale d'Histoire Naturelle, Paris), the senior author
studied the skeleton of a male manatee in Abidjan, Ivory Coast and found no evidence that more than a single species of African manatee exists. This agrees withprevious findings (Hatt, 1934; Kaiser, 1974; Rice, 1977; Husar, 1978).
Since then, the senior author has visited Dakar and Abidjan twice for preparatory survey on the status of the animals. In the summer (July-August) of 1980
and the winter (January-March) of 1981, the present authors shared in area toperform extensive field survey.
Brief report on the survey was aurally presented by the senior author at themarine mammal symposium, International Theriological Congress III on 17 August 1982 in Helsinki. The present report was rewritten with some corrections,particularly the estimation of living numbers were to be left to the future studies.
Sci. Rep. Whales Res. Inst.,

No. 34, 1982, 137-147

NISHIWAKI, YAMAGUCHI, SHOKITA, UCHIDA & KATAOKA

138

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METHOD
The principal method of survey was to collect information through interviewing
local zoologists or biologists, fishermen at market places and general inhabitants byshowing photographs of the animal. Information on the climate and other environmental conditions were also recorded. The group members often walked
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139

into the river valley, swamps or other places where manatees might occure. One of
the most difficult problem was to identify the animals in muddy colour who quietly
submerged in the water for most of the day and surfaced to breathe by exposing
only a small portion of the muzzle tip.
DATA COLLECTION

Senegal (Republique du Senegal)
Investigation on geographical and environmental conditions along the Senegal River was made to determine the northern and western limit of the distribution of
the manatee. Two group members flew from Dakar to Saint Louis and one ofthem further proceeded to Richar<l Toll, Podor, Matan along the border between
Senegal and Mauritania.
The Senegal River is very broad at its mouth where sand bar stretches to thesea and blocks high waves, so the water around the estuary is calm. Since thearea (Saint Louis as its center) is heavily industrialized, it seemed difficult for manatees to inhabit. Naturally no report of manatee sightings were obtained in thisarea. Similarly, we were unable to collect data of recent years in Dakar district.
This area which used to be a quiet lagoon has now turned to dry land. Recent
extreme dry weather apparently affected the river and subsequently the manatee
habitat.
Survey at Richard Toll was greatly facilitated by Dr. Morel, French ornithologist stationed there, through the cooperation of Dr. Alioune Ndiaye of Dakar.
According to Dr. Morel's information, manatees are decreasing, but a considerable
number of animals are still inhabiting Lac de Cuiers. At Matan, no report was
obtained to indicate the existence of manatee.
The Senegal River meets a flow from Lac de Cuiers and winds widely on its
way to Podor. The river is incredibly dark brown in colour and flowing further tothe vast land of savannah. There seemed to be little possibilities of the animals feeding on water grass, because no forage would be available in this area.
Therefore it seemed that manatees were not able to live there, at least from Lac deCuiers to Matan except in the secluded parts of Lake Lac de Cuiers and swamps.
Native people of Matan gave us no report of living manatees. Matan is so hot inJuly that even Dakar people feel it too hard. Environmental condition seemed to
be too severe for manatees to survive in summer. However since the head watersof Senegal River is said to be connected with that of the Niger River in the vicinityof Bamako during rainy seasons, there is possibility of some manatees are recruitedfrom the Niger to the Senegal. Based on what we have heard and on the examination of local conditions, a rough estimate of the manatee population in Senegal,
would be a few hundred.
Gambia (Republic of the Gambia)-Liberia (Republic of Liberia)
We only collected data that manatees were inhabiting the Gambia River.
To collect clear evidences of manatees existance there, our stay was too limited in
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NISHIWAKI, YAMAGUCHI, SHOKITA, UCHIDA & KATAOKA

Bissau (Republica da Guine-Bissau), Conarkry (Republique Populaire Revolutionaire deGuinee), Freetown (Republic of Sierra Leone) and Monrovia (Republic of Liberia).

Ivory Coast (Republique de Cote D' Jvoire)In the Ivory Coast geographical feature altered during August under influence of tropical rainbelt which shifts to the north in summer in the northernhemisphere (Beadle, 1978). In Abidjan, we exchanged all available informationand knowledge on manatees with Dr. Francis Laugine, French veterinarian anddirector of the Abidjan Zoo. With his assistance, we used cars and a small
plane of Cesna type for survey. We sighted considerable number of manatees invarious rivers, swamps and lagoons. This area holds a large population of manatees as well as the Niger does. The number of the animals in this country may
amount to several thousands. There were some suspicions that manatees were caught
and eaten by native people. Catch of manatees had been prohibited since the timeof French domination and was still in effect. But poachers catch and eat manatees
without leaving any evidence of carcass or bones and keep the fact secret for longtime. So there is no effective procedure of conservation. The situations are similar to dugong catch regulation in Indo-Pacific (Nishiwaki et al., 1981). Dr. Laugine plans a project of manatee research which may start in near future.
Ghana (Republic of Ghana) with information about Togo (Republique Togolais) andBennin (Republique Populaire du Bennin)
Investigation in Ghana was enhanced through the cooperation of Dr. Kazumori Minami of the Noguchi Memorial Institute for Medical Research, Universityof Ghana, and Dr. R. Kumar, Indian entomologist, of the Department of Zoology,
University of Ghana. Survey in the Lake Volta area was carried out under theirguidance. According to Dr. J. Vanderpuye, Ghanian researcher of Volta Basin
Research Project, no manatee inhabits the Akosombo dam area. Mr. A. K. Opoku
of the Volta River Development Authority, informed us that he heard a few years
ago that there had been abundant manatees in Asukawkaw River Arm, east coastof Lake Volta, about 9 km north to Akosombo. Dr. E.Q.A. Asibey of the Department of Game and Wildlife, Ministry of Forestry, told us that manatee catch was prohibited by law, and because of that, reports oflocal manatee catches hardly reachedto the government officer. However, one catch was reported in the West Arm of
Lake Volta in 1964 and another in Central Three Corner area in 1980, and someanimals were seen in the River Tano (west Ghana) sometime before, but none atpresent. During the construction of Akosombo dam which was completed in 1965,(Obeng, 1969), series of manatee skeletons were excavated, which are kept at the
Department of Zoology, University of Ghana: photographs of them were taken.
In the former description (Rappold, 1975), the manatee distribution was reported along the coast line of Ghana, but no fisherman in Cape Three Point, Elmina, Cape Coast, Accra, and of Terna, reported occurences of the animal in thesea. Although someone told us that an individual or individuals of such animal
were caught by fishing net in Angola, th_ere was no dependable evidence of the inSci. Rep. Whales Res. Inst.,
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cident. It was suspected, therefore, that the report might have been of dolphinsor sharks. Togo and Bennin seemed to be quite different in political, economic
and other features. There is little possibility of the manatee distribution, partly
because there is no big river such as the Niger or the Congo (Zaire) Rivers in theirterritories.
Through the assistance of Japan International Cooperation Agency (JICA),
we were able to obtain some information in a relatively short period of time.

Mali (Republique du Mali) and Niger (Republique de Niger)
In the vast desert area of extremely dry Mauritania (Republique Islamiquedu Mouritanie), northern Mali and the major land of Niger, exceptional green
patches can be seen in Mandingo Plateau in the up stream of the Senegal River.
The upper Niger River also reaches to this high plateau area with its central town
named Bamako, Mali. Although the river is not very wide at Bamako area, volumeof the river water fluctuates largely between dry and rainy seasons. The Niger
River flows to northeast and continues into the wilder area, forming Inland Niger
Delta, and reaches to Tombouctou (Timbuktu). After Tombouctou, the river
gradually turns to southeast and crosses the border to Niger.
Collected data in the area indicate that considerable number of manatees arein the Inland Niger Delta, and some are inhabiting the lower stream neigbouring
to Neamey, but the population size is scarcely known. The river basin is the only
place in the dry desert area for manatees to survive.
Nigeria (Federal Republic of Nigeria)
Investigation in this country resulted us something through the help of local
scientists. Dr. C. B. Powell of the School of Biological Sciences, University of Port
Harcourt, gave us a valuable report that abundant population of manatees had beenin Lake Kainji located in the middle flow of the Niger River and its tributary of the
Benue River. However, over killing caused the manatees to decrease in number
and now there may be a few hundred in the lake.
An important and reliable information was provided to us by Mr. A. B. Wilsonof the Nigerian Institute for Oceanography and Marine Research. He told usthat there were still many manatees in the Benue River. Although Dr. Powellspoke as a few hundred, his estimation was likely a few thousand. Dr. Akihiro
Takihara, Medical Officer of the Embassy of Japan to Nigeria, told us that he sawsome manatees kept alive by local people near by Makurde located on the side of
the Benue River.
People said that occurrences of manatees had been counted before (Rappold,
1975 ), but the number has been decreasing. Mr. Wilson informed us that an animal
was tangled in a fisherman's net at Port Harcourt. He identified the animal as amanatee by seeing our photographs. If it is true, his report sounds like a manatee
was taken from the sea, but the fact was that, Port Harcourt is located on the riverside, a little up stream from the mouth. Brackish waters may be flowing in fromtime to time, but salinity of waters is low in the very wide estuary. Some individSci. Rep. Whales Res. Inst.,
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NISHIWAKI, YAMAGUCHI, SHOKITA, UCHIDA & KATAOKA

uals might be washed out to the sea with strong current, against the animal's swimming effort.

Cameroon (Republique Unie du Cameroun)
The coastline of Cameroon faces the Gulf of Guinea, and it may be divided
geographically into two sections; high rocky coast of volcanic lava in the northwest
and low swampy and sandy coasts in the south (Ngwa, 1967). Because of this difference in topography, the west section (former British Cameroon) appears to haveno manatees in small and rapid rivers flowing down from the Mount Cameroon(altitude 4070 m, active volcano). A small Zoo (Zoological Garden) has been
estab.lished at Victoria, but its caretakers knew nothing about manatees in the district (South-West Cameroon). Fishermen in this town had some knowledge of theanimal, called " Maiga ", but they denied its occurrences.
There is a well-developed estuary, near the commercial capital of Douala,
into which two rivers (R. Mungo and R. Wouri) are flowing, and the local residents
informed us that there were manatees in the upstream of the River Mungo. However, the littoral district is heavily populated and urbanized, so it is hardly considered that there are large number of manatees. The Museum of Douala has apictorial display of a manatee as one of the significant components of the local fauna.
There may remain a considerable number of manatees in the Sanaga River
System, which is the largest in the country. Local residents interviewed at a riverside market at Edea described that the animal, called " Maga'', lived along theentire river except in the rapids, and that the manatees were eating grasses in theriver. Although it is prohibited to kill manatees by law, they occasionally catchthem for meat in order to entertain visiting dignitaries, with special permissions.
It appeared that, from what the people described, there were wide-spread incidents
of poaching activities, at least near the population centers. It is also told that there
was a licensed manatee hunter, Mr. Ngoye Samuel, at Mal Jeown near Mouanko
village, south of Douala, who possessed a special permit for manatee hunting, whichmight be for local festivity.
Gabon (Republique Gabonaise)
In the vicinities of Libreville, the capital of Gabon, manatees had been caught
very rarely from Baie de Mondah and Estuaire du Gabon. This report is based on
personal communication between the group members and the missionary people at
Donguila, and Dr. Domart, Direction des Chasses et Piches, Ministerie de !'Agriculture. The manatee is called as " Manga " in Gabon.
Approximately 150 km south to Libreville lies the city of Port-Gentil which islocated at the mouth of River Ogoue, the largest river in Gabon. Mr. Bayona ofOgoue Marine Service, who regularly commute between the city and off-shore oilrigs for servicing, informed us that he had not seen any manatee at sea, althoughseen large number of whales and dolphins passing in dry seasons. The local fishermen at Port-Gentil and also those at the neighbouring place of Ntchengue village
mentioned that manatees were common in the River Ogoue and in the several conSci. Rep. Whales Res. Inst.,
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RECENT SURVEY ON THE DISTRIBUTION OF AFRICAN MANATEE

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nected lakes located· between Port-Gentil and Lambarene. Several individual
persons informed equally that the manatees were also common in the southerncoastal lagoons, such as Lagune Nkomi or Fernan Vaz. near Omboue and Lagune
Ndogo, near Sette Gama. According to Mr.Jean Wack of Libreville, who worked
as a timber merchant soon after the World War II and travelled frequently along
the River Ogoue, manatees were abundant there before. He described that someexperienced fishermen would lie in ambush for the animals in the river because
manatees had moved onto a certain particular route every time in search of the food,species of aquatic plants.
Since Gabon is less extensively developed, it holds vast rain-forest area andriver basins with relatively smaller population of about 1.3 million people in about
270,000 km 2 (density about 5/km 2 ) (Hancock, 1978), there may be large population of manatee in some of the above-mentioned localities. One of the group member went into the wilder swampy Ivendo River area where manatees may inhabit
abundantly. One of our problems was that though experienced scientists may findthe muzzle tip or a part of the body in muddy water and estimate abundance in thearea, it is very difficult for them to count number of the animals. Relatively dense
distribution of animals was presumed. A rough estimate of manatees may be several thousands.
The government has prohibited manatee hunting, but the situation was thesame as everywhere, there seemed to have no efficient measures to prevent local
poachings.

Angola (Republica Populare de Angola) and Congo (Republique Populaire du Congo)
As we were refused to enter into Angola and Congo because of political unstability due to the civil war, no survey was carried out in those two countries.
Only information collected through Dr. Akihiro Takihara was that manatees wereseen in Stanley Pool, a lake nearby Kinshasa, Zaire (Republique du Zaire). No
manatee was said to be seen in the Ubangi River, a big tributary of the Congo (orZaire) River, which flows from the territory of Central African Republic (Enpire
Centrafrzcain ), passing through Bangui, crossing the border to Congo and flowing
into Stanley Pool.
The town of Lubumbashi is located near the border of Zambia (Republic ofZambia). A report came from the area that manatees, called " Manga " were seen
in remote rivers and swamps. However, since the body length of the animals reported were 30-150 cm, it was so doubtful that we concluded the report was false.
The southern and the eastern limit of manatee distribution is still unconfirmed.
DISCUSSION AND SUMMARY

As a result of the recent survey in the west African countries, it is clear that the mostabundant distribution of manatee is in the Niger River and its tributaries and associated swamps. The rivers which hold secondarly abundant populations are the
Sanaga and the Ivindo Rivers, in Cameroon and Gabon, respectively. The norSci. Rep. Whales Res. Inst.,
No. 34, 1982

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Sci. Rep.

Whales Res. Inst.,
No. 34, 1982

145

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manatee ( Trichechus senegalensis ).

Sci. Rep. Whales Res. Inst.
No. 31- ,1982

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NISHIWAKI, YAMAGUCHI, SHOKITA, UCHIDA & KATAOKA

them and the western limit of distribution is in the Senegal River system. However, dispersing and fading distribution in both the western and the northernparts of the river were so scarce that we had once thought that it might be better toreport the Inland Niger Delta in Mali as the northern limit and the Gambia Riveras the western limit.
The African manatee was proved to have a delicate sense to avoid salt water,which unlike the American manatee, Trichechus manatus, which inhabits marine
environment as well as estuarine and freshwater habitat (Odel et al., 1978; Erdman,
1970; Hartman, 1979). Some local reports telling manatees were observed at sea
were supposedly false and disregarded in our records. We thought that dolphins,
whales or sharks might have been mistaken for manatees in those cases.
Based on the all collected data, we drew a distribution map of the African
manatee in west Africa trying to show recent status of the animal and hoping that
it would be a reference to some conservation measures.
The Niger River flows through extensive areas crossing the borders of countries, merges with other rivers, and is very long. If conservation of the African
manatee would be planned, conservation strategy by a single country would not beeffective. A conserved population in one country may be poached in other territories. Only properly organized extensive and long standing project would workfor this purpose. Almost every country we visited, prohibits the manatee hunting
by law. But we were informed in many places that the actual status and conditionof manatees and poaching incidents had scarcely reached Government Officials because of people's fear of punishment. It should be noted that research projects byscientists stationing in the field for long periods, and who are able to establish goodterms with tribal chiefs and general local people of the district, are most desirable,
Dr. Laugini in Abidjan is a good example. Sufficient collection of local reports
and workable conservation plans would be available by those people.
While travelling many lands of severe natural conditions where many people
were nearly starved, we realized that the conservation of this species must be very
difficult because of delicious meat and easy hunting by local people. Saving thosepeople from poor status by developing agricultural and other improvement andprogress must have superior priority than establishment of conservation measureson manatee. However if we wait until these conditions are fulfilled, it should be
too late for conservation of the African manatee.
ACKNOWLEDGMENT

We should like to express our sincere gratitude to the number of people, scientists,
local residents, fishermen and so on, who gave us help in collecting information as
the greater part of study was based on those hearings. We specially appreciatefollowing people who kindly gave us particular helps and were able to have names
during the survey; Dr. Alioune Ndiaye, Director du Projet P.N.U.D. R.A.F.,
Senegal, Dr. G. J. Morel, Orstom, Richard-Toll, Senegal, Dr. F. Laugine, Zoo
D'Abidjan, Cote D'Ivoire, Dr. K. Minami and Dr. K. Minakami, Noguchi MemoriSci. Rep. Whales Res. Inst.,
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RECENT SURVEY ON THE DISTRIBUTION OF AFRICAN MANATEE

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al Institute for Medical Research, Accra, Ghana, Dr. R. Kumar, Department of
Zoology, University of Ghana, Legon, Ghana, Dr. E.QA. Asibey and Mr. C. K.
Manu, Department of Game and Wildlife, Ministry of Forestry, Ghana, Dr. J. N.
Raybould, Volta Lake Research and Development Project, Akosombo, Ghana, Mr.
D. N. Quaynor, Fishery Research Unit, Terna, Ghana, Dr. C. B. Powell, School of
Biological Science, University of Port Harcourt, Mr. A. B. Wilson, Nigerian Institute for Oceanography and Marine Research, Nigeria, Dr. Akihiro Takihara,
Messers Akikazu Nakamura, Norihiro Kobayashi, Daiko Okura, the Embassy ofJapan to Nigeria, Mr. James B. Ndeffo, Douala, Cameroon (guide, taxi-driver),Dr. Domart, Ministerie de I' Agriculture, des Eaux et Forets, Gabon, Dr. Jean
Wack, Libreville Gabon, Mr. Jean-Pirre Bayona, Port-Gentil, Gabon, Dr. Jean L.
Deval, IRAF, Gabon, Prof. T. Kano and Mr. T. Takeda, University of the Ryukyus,
Japan, and from the preparatory survey by the senior author, till the end of thisstudy, Miss Marie-Jeanne Ndiaye of the Broad Casting Station, Dakar, Senegal,
has given us generous help in collecting information, contact among group members while travelling and valuable advices for our survival in the countries quite
different from home, who has understandings in Japan and Japanese since she has
been in Japan for technical study.
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BEADLE, L. C., 1978. The inland waters of tropical Africa. Longman, London, 368 pp.
ERDMAN, D.S., 1970. Marine mammals from Puerto Rico to Antigua. J. Mamm., 5(3): 636-639.
HANCOCK, G. (ed) 1978. African guide. World of information. England., 366 pp.
RAPPOLD, D.C.D., 1975. Large mammals of west Africa. Longman Group Ltd., London.
HARTMAN, D.S., 1979. Ecology and behavior of the manatee (Trichechus manatus) in Florida. Special publication No. 5, The American society of mammalogists.
HATT, R. T., 1934. The American museum Congo expedition, manatee and other recent mammals. Bull.
Amer. Mus. Nat. Hist., 66: 533-566.
HusAR, S. L., 1978. Trichechus senegalensis, Mammalian species No. 89, The Amer. Soc. mammalogists., Institut
Pedagogique Africa et Malagache ed., 1975. Geographie. Classiques Hachette.
KAISER, E. K., 1974. Morphology of the sirenia. S. Karger.
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NGWA, J. A., 1967. A new geography of Cameroon. Longman, London, 151 pp.
OBENG, D. K., 1969. Man-made lakes. Ghana Univ. Press.
0DEL, D. K.,J. E. REYNOLDt and G. WAUGH., 1978. New records of the west Indian manatee Trichechusmanatus from the Bahama Islands. Biol. Conserv., 14: 289-293.
RrcE, D. W., 1977. A list of the marine mammals of the world. NOAA Tech. Rep. NMSF. SSRF. US Dept.
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No. 34, 1982