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Location Madagascar, Mahajanga
Central coordinates 46o 31.00' East  15o 55.00' South
IBA criteria A1, A2, A3, A4i
Area 78,814 ha
Altitude 0 - 25m
Year of IBA assessment 2001

Asity Madagascar (Affiliate)

Site description The site lies 20 km from Mahajanga. Bombetoka Bay is delimited, in the north, by a line from Katsepy in the west to the headland just north of Boanamary in the east, and, in the south, by the Marovoay flood-plain. The bay consists of mangrove islets (c.43,500 ha) separated by channels (c.21,500 ha at high tide) and mudflats (c.8,500 ha at low tide), with shallow subtidal waters in the estuary. The water is shallow (less than 5 m deep at low tide), except towards the mouth, and is very turbid. Northern mangroves are relatively degraded (3–4 m high), while those toward the south are in better condition; likewise, those on the coast are more intact than those in brackish, inland areas, where the canopy is 6–8 m high. The largest mudflats lie immediately seaward of the mangrove islets. A muddy bar crosses the mouth of the estuary, c.10 m wide and covered with scattered mangroves. The Marovoay wetlands comprise a vast area of rice-fields, marshes with Cyperaceae, and a large reservoir, Lake Amboromalandy.

Key Biodiversity See Box and Tables 2 and 3 for key species. Sixty species are known from the site, of which 10 are endemic to Madagascar. The occurrence of a large, seasonal congregation of Anas bernieri (the largest known), and of several individuals of Threskiornis (aethiopicus) bernieri, in the Bombetoka estuary, is notable. The eastern part of Lake Amboromalandy is very rich in waterbirds.

Non-bird biodiversity: Sirenian: Dugong dugon (VU; present, according to local people).

Populations of IBA trigger species

Species Season Period Population estimate Quality of estimate IBA Criteria IUCN Category
Madagascar Teal Anas bernieri resident  1997-1998  85 individuals  A1, A2, A3, A4i  Endangered 
Madagascar Grebe Tachybaptus pelzelnii resident  1997-1998  present  A1  Vulnerable 
Lesser Flamingo Phoeniconaias minor non-breeding  1997-1998  present  A1  Near Threatened 
Madagascar Heron Ardea humbloti resident  1997-1998  present  A1, A2, A3  Endangered 
Great White Egret Ardea alba non-breeding  1997-1998  700 individuals  A4i  Least Concern 
Egretta dimorpha non-breeding  1997-1998  286 individuals  A4i  Not Recognised 
Madagascar Fish-eagle Haliaeetus vociferoides resident  1997-1998  present  A1, A2, A3  Critically Endangered 

Land use

Land-use Extent (% of site)
agriculture -
hunting -
water management -
other -
Notes: Collection of eggs and young of waterbirds.

References Delacour (1932), Hawkins (1993a), Langrand (1987), Rabarisoa (1994), Rabarisoa et al. (1995), Ségalen (1956), Thorstrom and Rabarisoa (1995), Watson et al. (1993).

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Recommended citation  BirdLife International (2016) Important Bird and Biodiversity Area factsheet: Bombetoka Bay - Marovoay NPA. Downloaded from on 27/10/2016

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