http://dr.lib.sjp.ac.lk/handle/123456789/753 Thu, 23 Apr 2026 10:23:06 GMT 2026-04-23T10:23:06Z http://dr.lib.sjp.ac.lk/handle/123456789/808 The Species Composition, Abundance and the Distribution of Seagrass Communities in Puttalam Lagoon Jayasuriya, P.M.A. 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. Tue, 01 Jan 1991 00:00:00 GMT http://dr.lib.sjp.ac.lk/handle/123456789/808 1991-01-01T00:00:00Z http://dr.lib.sjp.ac.lk/handle/123456789/807 The Distribution and the Species Composition of the Existing Mangrove Vegetation around Chilaw Lagoon Jayasuriya, P.M.A. The distribution pattern, species composition, zonation and the abundance of the mangrove communities around Chi/aw lagoon were studied. 15 typical mangrove species and 13 mangrove associates were listed. Quadrat sampling analysis shows that most of the western part of the lagoon is dominated by Excoecaria agallocha and Aegiceras corniculatum. Line transect analysis shows a prominent border to Rhizophora apiculata near the shore around most parts of the lagoon. Some rare mangrove species such as Xylocarpus granatum is common in the islands of Chi/aw lagoon. Mangrove area has been reduced due to the new developments and expansion due to aquaculture. Tue, 01 Jan 1991 00:00:00 GMT http://dr.lib.sjp.ac.lk/handle/123456789/807 1991-01-01T00:00:00Z http://dr.lib.sjp.ac.lk/handle/123456789/806 Preliminary Observations on the Purse Seine Fishery in the South-west Coast of Sri Lanka Dayaratne, Pauline Purse seine fishing in the south west coast of Sri Lanka became popular since 1982 and the number of boats increased to about 29 in 1984. In 1987 there were around 50 purse seiners operating in this region. A study of the purse seine fishery and its impact on other small scale fisheries were initiated in 1985. The paper presents the results of a surveyfor the period 1985 to 1987. Purse seinefishery is carried out only during the calm months (ie from October to April). 3 1/2 ton boats with inboard engines are used in this fishery. The length of the nets range from 150-210 meters and has an average depth of about 50 meters. The average catch per unit effort for purse seiners for 1985/86 season was about 185.7 kg/boat. The total production by the purse seine fishery in this area in 1987 was about 250 MT. This contributes to about 30% of the total small pelagic fish production in this region. Amblygas.er sirm dominates the purse seine catch. Other important species are Decapterus russelli, Rastrelliger kannagurta and Loligo singhalensis. Length frequency distribution studies of A. sirm show that the purse seiners fish in the same area and probably fish the same stocks as the small mesh gill netters in this region. Tue, 01 Jan 1991 00:00:00 GMT http://dr.lib.sjp.ac.lk/handle/123456789/806 1991-01-01T00:00:00Z http://dr.lib.sjp.ac.lk/handle/123456789/805 Marsh Vegetation of Muthurajawela Herat, Tissa R. Biologically marshes are among the richest, most productive ecosystems known and among the most interesting. Muthurajawela marsh is one such wet land which has a great effect on maintaining the proper ecological balance of the mangrove vegetation and the fauna and flora of the Negombo lagoon. An attempt is made here to understand the distribution patterns of vegetation, plant species of ecological significance and of special human interest, and to find out, if any, the presence of rare endangeredplants. It is hoped that the present study would be an initial step for much more detailed ecological studies of the ecosystem. Tue, 01 Jan 1991 00:00:00 GMT http://dr.lib.sjp.ac.lk/handle/123456789/805 1991-01-01T00:00:00Z