The Species Composition, Abundance and the Distribution of Seagrass Communities in Puttalam Lagoon

Abstract

The species composition, abundance and the distribution of different seagrass beds of Puttalam lagoon have been investigated. Eight species belonging to six genera were recorded during the investigation i.e., Enhalus acroida (I. F..)Royle Thalassia hemprichif (Ehrenb.) Aschers., HaIodule uninervis (Forsk.) Aschers in Bossiser, Syringodium isoetifolium (Aschers.) Dandy, Cymodocea rotundata Ehernb. et Hempr. ex Aschers., Cymodocea serrulata(R. Br.) Aschers, and Magnus, Halophila ovalis (R. Br.) Hook. F. and Halophila decipiens Ostenfeld. Two varieties of Halodule uninervis (narrow and wide) were also recorded during this investigation. The distribution pattern of the different species of seagrass beds showed a close association with different salinity values of the lagoon. It was found that the narrow variety of Halodule uninervis covered 75% of the potential areas of the lagoon. It was also observed that Enhalus acroides, Cymodocea serrulata and Thalassia hemprichii play a major role as substrata lor many important epiphytic forms of macro and micro algae. It was also discussed thai traditionalfishing methods prevailing in this lagoon show til great threat to the 'survival of the seagrass communities.