Jaffna Lagoon

Location: 90 50’ 0 N and 790 50’ 0 E to 90 20’ 0 N and 800 30’ 0 E; 1087208 N and 372066 E to 1031744 N and 445094 E; adjoining Palk Bay, in the Jaffna, Kilinochchi and Mannar Districts, of the Northern Province.

Area: c. 45,000 ha

Altitude: Sea level

Overview: The Jaffna lagoon is a semi-enclosed water body connected to the Palk Bay. It is surrounded by a dry zone land mass and due to being more greatly influenced by freshwater input, has different physical conditions to that of the larger Palk Bay. The lagoon contains a number of coastal wetland habitats and is an important breeding area for numerous marine species. Jaffna lagoon has been identified as an IBA by BirdLife International.

Physical features: The lagoon opens into the north eastern part of Palk Bay by way of three narrow openings and one wide opening, and is also influenced by tides in the Bay. The lagoon is long and narrow, extending from Elephant Pass in the southeast to Kayts in the northwest. The lagoon is relatively shallow with the maximum depth being less than 3 m. The shoreline is composed mostly of sandy soil while the bottom is mostly mud. The salinity in the lagoon is greatly influenced by rainfall and freshwater run-off from surrounding areas, and varies from a low of around 10.3 ppt during the rainy season to a high of around 45.49 ppt during the dry season. The lagoon is located in the dry semi-arid zone with an average temperature of around 270 C and an annual rainfall between 500-700 mm. Most rain is received during the northeast monsoon from October to February.

Ecological features: The lagoon is surrounded by a dry zone land mass dominated by sandy areas and dry zone scrublands. The lagoon contains extensive inter-tidal mudflats while mangroves are found along the shores of the lagoon. The shallow depths and muddy substrate support prawns, crabs and small fish species such as leiognathids, engraulids and clupeids.

Noteworthy fauna: The lagoon and adjoining areas are important for numerous waterbirds.

Noteworthy flora: Predominantly mangroves

Land use: Fisheries, particularly prawn fisheries.

Possible changes in land use: Fisheries are currently restricted due to the security situation and would increase if the security improves in the area. Vegetation such as mangroves is liable to be cleared for security reasons.

Hydrological and biophysical values: The lagoon plays a role in flood control during times of heavy rainfall. Being part of the larger Palk Bay area it plays an important role in regimenting tidal movements, currents and salinity in surrounding water bodies.

Social and cultural values: Fisheries have been important economic activities of coastal communities, and many are engaged in small scale fisheries using traditional methods such as cages, traps and cast nets.

Scientific research and monitoring: Some studies have been undertaken by the Jaffna University and the DFAR prior to the conflict situation.

Conservation education: Information not available

Recreation and tourism: Information not available

Conservation measures taken: Information not available

Conservation measures proposed: The Jaffna lagoon has been proposed as a SAM site by the CCD.

Disturbance and threats: Clearing of shoreline vegetation for security reasons has degraded much of the mangroves in the area. The development of the Sethusamudram Ship Canal is also likely to impact upon the ocean circulation, physical conditions and biological cycles within the Palk Bay area, and could affect the biodiversity and biological cycles within the lagoon.

Land tenure: State owned

Management authority and jurisdication: DFAR for managing fisheries, and the CCD for management of the coastal zone. The Jaffna DSS also has jurisdiction over adjoining lands.

References: Sachithanathan (1969); Sachithanathan and Perera (1970); Sivalingam (2005)