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Location Madagascar, Toamasina
Central coordinates 48o 26.00' East  17o 34.00' South
IBA criteria A1, A2, A3, A4i
Area 90,000 ha
Altitude 750 - 790m
Year of IBA assessment 2001

Asity Madagascar (Affiliate)

Site description This is the largest lake in Madagascar, situated 170 km north-east of Antananarivo and 7 km north of Ambatondrazaka. It lies in a tectonic basin 40 km long and 9.5 km wide, located between the Grand Angavo escarpment in the west and the Mangoro–Alaotra escarpment in the east. Its depth is 1.0–2.5 m during the low-water season and 4 m during the high-water season. The water is fresh, and turbid with suspended silt due to intense erosion of the deforested hills that surround the lake. The lake is fed by the Sasomanga and Sahabe rivers in the south, and by the Sahamaloto and Anony rivers in the north-west. The only drainage river, the Maningory, flows out of the north-eastern part of the lake. The lake-bottom sediments consist of thick layers of sand, black mud and grey clay. Natural, permanent marshes occur along the lake margin, especially in the southern part of the site. The largest are located to the south and east of the Antanamalaza peninsula and in the part drained by the Maningory. There are also wet grasslands. The lake vegetation was formerly dominated by water-lilies Nymphaea, but these have decreased in extent due to competition with non-native water-hyacinth Eichhornia and water-fern Salvinia. In the marshes, sedges Cyperus and reeds Phragmites dominate. Secondary savanna covers the surrounding hills.

Key Biodiversity See Box and Tables 2 and 3 for key species. Eighty species are known from the site, of which 13 are endemic to Madagascar. Lake Alaotra is an exceptional site for waterbirds. It formerly held two highly threatened endemic species, which were probably confined to the lake, but which may now be extinct: Tachybaptus rufolavatus and Aythya innotata. The former was last recorded in 1985 and the latter in 1991. Furthermore, the flocks of Anas melleri that occur on the lake constitute the largest congregations known for this species, and Ardea humbloti also occurs regularly (in its only eastern site), though it is not proven to have bred.

Non-bird biodiversity: Lemur: Hapalemur griseus alaotrensis (CR). Carnivore: Salanoia concolor (VU).

Populations of IBA trigger species

Species Season Period Population estimate Quality of estimate IBA Criteria IUCN Category
Meller's Duck Anas melleri resident  1993-1994  150 individuals  medium  A1, A2, A3, A4i  Endangered 
Madagascar Pochard Aythya innotata resident  1991  present  A1, A2, A3  Critically Endangered 
Alaotra Grebe Tachybaptus rufolavatus resident  1985  unknown  A1, A2, A3  Extinct 
Madagascar Grebe Tachybaptus pelzelnii resident  1993-1994  1 individuals  medium  A1  Vulnerable 
Madagascar Pond-heron Ardeola idae non-breeding  1993-1994  7 individuals  medium  A1  Endangered 
Madagascar Heron Ardea humbloti resident  1993-1994  8 individuals  medium  A1  Endangered 
Madagascar Marsh-harrier Circus macrosceles resident  1993-1994  4 individuals  medium  A1  Vulnerable 
Madagascar Rail Rallus madagascariensis resident  1993-1994  12 individuals  medium  A2, A3  Vulnerable 
Madagascar Snipe Gallinago macrodactyla resident  1993-1994  37 individuals  medium  A2, A3  Vulnerable 

IBA Monitoring

2009 not assessed not assessed low
Good - based on reliable and complete / representative data

Whole area of site (>90%) covered by appropriate conservation designation  No management plan exists but the management planning process has begun  Very little or no conservation action taking place  low 


IUCN habitat Habitat detail Extent (% of site)
Wetlands (inland) Freshwater lakes and pools; Permanent herbaceous swamps and bogs; Rivers & streams  major

Land use

Land-use Extent (% of site)
agriculture -
fisheries/aquaculture -

Further web sources of information 

Alliance for Zero Extinction (AZE) species/site profile. This site has been identified as an AZE due to it containing a Critically Endangered or Endangered species with a limited range.

References Delacour (1930), Hawkins et al. (2000), Nicoll and Langrand (1989), Payne (1960), Pidgeon (1996), Rand (1936), Voous and Payne (1965), Wilmé (1993), World Wide Fund for Nature–Madagascar (1997), Young and Smith (1989).

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Recommended citation  BirdLife International (2016) Important Bird and Biodiversity Area factsheet: Lake Alaotra NPA. Downloaded from on 23/10/2016

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