Closing the knowledge gap of seagrass habitats in Sri Lanka

August 22, 2016

LK5 Project Update: Jan thru June 2016

In the first half of 2016, NARA’s activities contributed entirely to covering the knowledge gap on seagrass habitats in LK5’s study area.

NARA conducted a desk review of existing seagrass data and prepared base maps of the sampling locations from Mannar to Jaffna. The field studies revealed diverse seagrass patches along the coastal area from Walepadu to Iranathivu islands.

Samples were also taken from locations near Palk Bay, and coastal areas around Jaffna islands. Enhalus acroidas followed by Cymodacea were the two most present seagrass species. Halophila and Halodule, which were the major constitutes of the stomach content of dugongs analysed by NARA, were found in tiny patches in the study areas.

NARA also studied the threats to seagrass habitats. The survey initiated a ranking of the impact of fishing gears on seagrass beds and associated seagrass fauna. Illegal fishing gears on the seagrass beds, such as gill nets, trammel net, disco nets, monofilament and bottom set gill nets were still used by the communities, causing damages to the habitat. Some marine aquaculture, such as commercial seaweed farming, was also found to be degrading seagrass beds.

NARA made also water analyses and discovered that some seagrasses were damaged due to environmental pollution – anoxic conditions were observed and higher phosphates in the water column were observed in some locations. Seasonal loss (dying) of seagrasses was observed in the shore area.