Mapping of Geohabitats of the continental shelf of Tamandaré-PE
Reefs; continental shelf; Tamandaré Bay; Marine Protected Area; paleochannels
The Tamandaré-PE continental shelf, in the eastern Brazilian coast, is narrow (35 km), shallow with shelf break at 90 m water depth, has mixed carbonate and siliciclastic sedimentation and widespread occurrence of ridges and patch reefs. The habitat mapping was carried out using an interferometric swath system (EdgeTech 4600), digital processing of Landsat 8 image, surficial sediment samples and underwater videos to identify sedimentary cover zones and reef fields. Seven acoustic backscatter patterns represent hard-substrate habitats associated biogenic reefs (P1, P2 and P3) and soft sediment habitats where muddy to gravelly substrates develop (P4, P5, P6 and P7). Reefs attached to the Tamandaré Bay and coast have more complex relief with average of 4 m high with steep flanks and caves, reaching 10 m height in the seaward flanks. A second reef field, the Carapitanga Reef, has lower relief with average height of 2 m, but with knolls up to 6 m high, and depicts an advanced bioerosion stage. A muddy body occurs in between reef fields and into paleochannels, where there are large shrimp fishing activities.