May 22 is the International Day for Biological Diversity. This year’s theme is the biodiversity of islands. Sri Lanka is often referred to as a biodiversity hot spot, but one of its key ecosystems, coastal lagoons, have rarely received much attention. A new report seeks to highlight their importance and improve steps towards sustainable management.

Freshwater fishing in Negombo lagoon Photo: Hamish John Appleby/IWMI
Freshwater fishing in Negombo lagoon
Photo: Hamish John Appleby/IWMI

Negombo Lagoon is just a short drive north from Sri Lanka’s bustling capital, Colombo. Every few minutes huge airliners sweep in over its waters to land at the nearby international airport. Yet, despite its close proximity to the metropolis, the lagoon is alive with wildlife. Dozens of fisherfolk make a living from its shallow waters, and the local markets teem with freshly caught shrimps and fish.

Sri Lanka’s coastline is dotted with brackish lagoons. Until recently, there had been no systematic attempt to survey and document these unique ecosystems. Now, a newly published report, Lagoons of Sri Lanka: From the origins to the present, published by the International Water Management Institute (IWMI), has assessed the state of the country’s 82 lagoons and highlighted the challenges they are likely to face in the twenty-first century.

The research team visited a variety of lagoons along Sri Lanka’s nearly 1,400 kilometers of coastline, interviewing local residents and lagoon users. They wanted to understand the social and economic value of the lagoons as well as their natural wealth.

Women inspecting the catch Photo: Hamish John Appleby/IWMI
Women inspecting the catch
Photo: Hamish John Appleby/IWMI

“The great variety in the types of lagoons is striking,” says IWMI’s Herath Manthrithilake, one of the authors of the report. “Some of the lagoons on the southeast coast are almost completely cut off and have very high salt levels. Consequently, wildlife is scarce. Others are more open, and are constantly replenished by tides and diluted by streams, rivers and canals draining into the water. These are often fantastically productive and biodiverse.”

For many years the lagoons had attracted little interest beyond the local communities that relied on them for fishing and other wetland products such as reeds. Recently, however, local groups have woken up to the fact that the lagoons could be a draw for tourists. Sri Lanka is undergoing a tourism boom. Visitor numbers are currently rising by 30% a year and many are attracted by the island’s spectacular wildlife. The opportunities for new livelihoods are clear, but competing lagoon users may have very different ideas about how best to manage the resource.

Photo: Hamish John Appleby/IWMI
Man crossing the Kelani river
Photo: Hamish John Appleby/IWMI

“We need to better understand the social and economic value of our lagoons,” continues Manthrithilake. “We know that many are biodiversity hot spots, but we can make a better case for their sustainable management if we can work out how they interact with people’s livelihoods. This report is a first step, but much more research will need to be carried out to ensure that the island’s lagoons endure as thriving community resources.”

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Silva, E.I.L.; Katupotha, J.; Amarasinghe, O.; Manthrithilake, H.; Ariyaratne, R. 2013. Lagoons of Sri Lanka: From the origins to the present. Colombo, Sri Lanka: International Water Management Institute (IWMI). 116p.