Checklist of known ascidans from Vizhinjam bay, Kerala.
More than hundreds of species of ascidians have been reported to foul marine structures. In the current study ascidian samples were collected from three different habitats of Vizhinjam bay, during 2010 to 2012. The collection of the specimens were done during the low tides level, from a rocky intertidal area (station 1), bio fouling community of the pearl oyster cages of the CMFRI during the brushing process (station 2), and artificial seawalls such as cement block and pilling hull of barges. A total of 20 species of ascidians including 13 colonial and 7 solitary ascidians were recorded from the different habitats of Vizhinjam coast. In total of 20 species of ascidians collected, 19 species are non-native ascidians and 1 is native ascidian (Plate 1. 2 to 1. 9). Among the 19 nonnative ascidian species 16 are cryptogenic species and 3 are invasive. These cryptogenic species belongs to diverse families with maximum representation of Didemnidae (6 taxa), followed by Polyclinidae (5 taxa), Pyuridae (3 taxa), Styelidae (3 taxa), Ascidiacea (2 taxa) and Polycitoridae (1 taxa). Boulders, pier pilings and concrete stones present in the Vizhinjam coast can provide excellent habitat for the variety of sedentary organisms.