The site consists of 12 main islets, in three groups: (1) northern sandy islets: Nosy Foty (6 ha), Nosy Fasy (5 ha), Nosy Faty (1 ha) and Nosy Hao (10 ha); (2) northern rocky islets: Nosy Hara (115 ha), Nosy Vaha (1 ha), Nosy Lakandava (5 ha) and Nosy Anjombavola (30 ha); and (3) southern islets: Nosy Anambo (10 ha), Nosy Valiha (150 ha), Nosy Tanga (50 ha) and Nosy Manonoka (75 ha). The northern rocky islets are karstic and covered by a mixture of grassy vegetation and xerophilous shrubland including Pachypodium. The sandy islets are flat, covered by grass, Ipomoea mats and small Casuarina trees. The southern islets are more or less rocky, except Nosy Anambo, which is flat and sandy. The rocky islets are often covered by trees and palms such as Bismarckia. The islets are surrounded by coral reefs. Four other rocky islets north of Manonoka also support some breeding bird species.
See Box and Table 3 for key species. The site is home to two pairs of Haliaeetus vociferoides: one pair on Nosy Tanga, next to Cape St Sébastien, and one pair on Nosy Hara in the centre of the archipelago. Significant numbers of terns, including Sterna caspia, S. dougallii, S. fuscata, S. bengalensis, Anous tenuirostris and A. stolidus, have been observed on Nosy Fasy, Nosy Foty, Nosy Faty and Nosy Valiha, not all of them breeding. In July 1997, on Nosy Fasy, about 600 pairs of S. bergii (with 50 young) and 2,000 pairs of S. fuscata were recorded, while on Nosy Foty there were 1,500 pairs of S. bergii (60% breeding, with c.300 young), 30 pairs of S. fuscata and 50 pairs of S. caspia (with young), and on Nosy Faty there was a flock of S. dougallii.
Non-bird biodiversity: Marine turtles are present.
BirdLife International (2021) Important Bird Areas factsheet: Cape Anorontany Archipelago NPA. Downloaded from http://www.birdlife.org on 05/12/2021.