Volume 03 No. 02 July 1991
http://dr.lib.sjp.ac.lk/handle/123456789/753
2024-03-28T21:31:54ZThe Species Composition, Abundance and the Distribution of Seagrass Communities in Puttalam Lagoon
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.
1991-01-01T00:00:00ZThe Distribution and the Species Composition of the Existing Mangrove Vegetation around Chilaw Lagoon
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.
1991-01-01T00:00:00ZPreliminary Observations on the Purse Seine Fishery in the South-west Coast of Sri Lanka
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.
1991-01-01T00:00:00ZMarsh Vegetation of Muthurajawela
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.
1991-01-01T00:00:00Z