An urban safe haven

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A little pocket of water on an island in the middle of the Heen Ela Sanctuary is where a small number of fish with white spots on their heads were discovered. Surrounded by the greenery of trees and shrubs this island provides just the right shade needed for the Day’s Killifish to breed and survive.  

Where they came from still remains a mystery and it is believed that they may have been there right along or washed to the island by the river water. But no matter where they came from they are now here to stay and breed, in an environment that is safe and protected from predators and human destruction.  

The Heen Ela marsh is the nearest remaining marshland to the Colombo city and consists of about 45.32 hectares (112 acres) and five natural islands. The marsh is situated in Rajagiriya Kotte of the Sri Jayawardenapura Divisional Secretariat in the Colombo district. The Heen Ela marsh was declared a sanctuary in September 2021.

Many years ago the Heen Ela marshland was a paddy field. After 1977 cultivation ceased in this paddy field and water hyacinth, hydrilla and hundreds of over grown trees, bushes and ferns started to grow there. Inside this marsh lay a rich biodiversity and animal life that many people were yet to discover. Unknown to many this marsh is home to many varieties of birds, fishing cats, water monitors, porcupines, otters, water snakes, terrapins and two types of bats (fruit bats and Micro Chiroptera bats, that eat around 3,000 insects a day and around 1,000 mosquitoes per day at night).

Exotic freshwater fish

The Flying Fox (Maha Waula), the Grey Heron, Purple Heron, Brahminy Kite, Large Egret, Intermediate Egret, Little Egret and the Purple Coot (Purple Swamp Hen), monitor lizards, the Sri Lanka Keelback Water Snake, the Saltwater Crocodile – the largest reptile in the world, the Indian Green Frog, the Sri Lanka Wood Frog, 11 species of butterflies and 11 species of dragonflies are among the other species found in this marsh.

In 2003 President, Organisation for Aquatic Resources Management (OARM), Shantha Jayaweera, did a brief study on the birds in the Heen Ela marsh and found that there are around 73 species of birds out of which 40 are aquatic or marshland birds. Then came the discovery of another new exotic freshwater fish found in the Heen Ela marsh.

An adult pair of the Robertson’s Cichlid also known as the False Fire-mouth Cichlid or the Turquoise Cichlid (Amphilophus robertsoni) was discovered by Jayaweera and V.G.Samantha of OARM on 14 August 2018.

“The pair of Robertson’s Cichlids were caught in a fishing net and later identified by Jayaweera. The female Robertson’s Cichlid was injured after it was caught in the net and died. But the male Robertson’s Cichlid who had minor injuries to its tail and fins survived. The male fish was 17 ½ cm long. This new exotic fish species belongs to the ornamental fish trade and is not found in Sri Lankan waters,” Jayaweera said.

The latest discovery at the Heen Ela marsh is the Day’s Killifish (Aplocheilus dayi) also known as the Uda Handaya or Nala Handaya. Endemic to Sri Lanka the fish was named after the Inspector-General of Fisheries in India Francis Day (1829-1889), who first reported this fish, but identified it as Aplocheilus panchax at the time. The males and females have a black dot at the rear end of the base of their dorsal fin. They are dorsally olive and laterally dull yellow in colour and the entire body has tiny, jewel like, emerald coloured reflective spots interspersed with tiny red dots. The females lay 50 to 150 eggs and its diet consists of small insects, insect larvae and fish fry.  

Three species of killifish

“There are three species of killifish – the Day’s Killifish, the Werner’s Killifish (Aplocheilus werneri) and the Dwarf Killifish (Aplocheilus parvus) – in Sri Lanka. The Day’s Killifish and the Werner’s Killifish are endemic and endangered to Sri Lanka while the Dwarf Killifish is indigenous to Sri Lanka. The endemic Killifish live in the lowland wet zone,” Jayaweera explained.

He said they are found in the Ratnapura District and the Kalutara District and the male grows from 5 to 6 cm long while the female is a little smaller. “Their body is shaped in such a way as to live on the surface of the water. Their dorsal area is straight and they live on the surface. Its dorsal fin is towards the back of the fish. They have a shiny green colour and the mouth is a semi-circle shape. The Day’s Killifish are not very active. They catch and eat insects that fall into the water. When they get scared they go underwater. They live in shady, shallow and clear water,” Jayaweera said.

He added that due to development their habitat is destroyed and if the water area they live in is interrupted they cannot live there. “If the trees over the stream are cut and the water gets hot the Day’s Killifish cannot survive there. They need vegetation on both sides of the water to survive. In Colombo areas there are only a few small habitats left for the Day’s Killifish. You find killifish in rivers, streams and canals. But the Day’s Killifish is only found in shady areas with shrubs and trees as mentioned,” Jayaweera explained.

They are found in pocket areas, in areas where there is a slow movement of water or a movement of water, he says, and streams drying up due to the building of houses and the cutting of trees has resulted in loss of habitat. “The use of pesticides during cultivation has also contributed towards the loss of this species. They get destroyed when digging to erect canals. The Day’s Killifish was earlier found in the Attidiya sanctuary but is now no more. Due to a decrease in numbers the International Union for Conservation of Nature (IUCN) has listed the Day’s Killifish as Endangered,” Jayaweera said.

Day’s Killifish in Heen Ela

They are presently found in the Baddegana Wetland Park and the Diyasaru Park said Jayaweera. “This killifish species is found in estuaries and not in main canals. They can also be found in areas where rain water gets collected. A small number was found at the Heen Ela Sanctuary recently. The Heen Ela Sanctuary has many small islands and these islands have streams with a slight flow of water. When we did a research in this area more than 20 years ago we found the Day’s Killifish in a marshy area at one end of the Heen Ela. Now there are no fish in this area because the paddy fields are cut and the area destroyed,” Jayaweera said.

He went on to say that the area was dug up and large pools made and all the fish got wiped out. “We went to this island before but didn’t find any fish. But this time when we went to the island we found some fish in small numbers. This island is different to the other islands in the sanctuary because it has a good habitat that is suitable for the Day’s Killifish. The island has small shrubs, small streams and a muddy area. The fish could have washed to this island with the river water and started breeding there because the habitat is good for them. We don’t know for sure how they came there,” Jayaweera explained. 

Jayaweera is hoping to bring more fish from the Diyasaru Park and Baddegana Wetland Park to increase breeding and also to introduce new genes to the existing fish at the Heen Ela Sanctuary.

This island presently has 30 fish species, says Jayaweera and they include the Hora Dandiya endemic to Sri Lanka, the Spiketail Paradise Fish (indigenous), the Snakeskin Gourami and the Sri Lanka Walking Cat Fish. “Most of the Walking Cat Fish species are no more because scavengers released into these areas have eaten them. The Spiketail Paradise Fish and the Snakeskin Gourami are both found in slow flowing water areas. Some of these fish have come from the sea, others were introduced to this area and others are indigenous. Half the fish species found on this island are those that were introduced,” Jayaweera said.

Biggest marsh linked to the Colombo city

“The Heen Ela Sanctuary is the biggest marsh linked to the Colombo city. It was declared a sanctuary by the Environment Ministry last year. I told the Environment Ministry Secretary Anil Jasinghe that Heen Ela is a high biodiversity area and should be declared as a sanctuary. The Biodiversity Secretariat and the Environment Ministry were informed about the importance of this area,” Jayaweera explained.

Today, the Heen Ela marsh is not what you would see many years ago. The Heen Ela marsh area belongs to the Sri Lanka Land Reclamation and Development Corporation (SLRDC). Prior to it being declared a sanctuary it was overgrown with water hyacinth and salvinia. It was polluted with plastic and polythene. The water was dirty and mucky. 

At the time a plan was drawn up by the OARM to make this area habitable for birds and animals. The project cost is Rs 6.2 million and is funded by the United Nations Development Program (UNDP). The UNDP/GEF/SGP Project started cleaning the marsh in 2018/2019. Today, the water is clear, the area is rich in biodiversity and fauna and flora are flourishing.

“The marshlands in the Colombo area need to be protected as many are destroyed annually to make way for development. In lowland wetlands in Sri Lanka, marshy bog lands are one of the richest in diversity and make them one of the most important eco systems within this eco region. But for the past 30 years, within the Colombo metro region as well as in the surrounding areas, explosive population increases due to natural birth rates as well as the internal migration for new economic and social opportunities, there has been a steady increase of pressure for successive governments to release more lands for housing and other infrastructure,” Jayaweera said.

Today, there are only a few isolated marshes he says that remain intact, providing vital refuge to the remaining wild life and native flora and the Heen Ela sanctuary/ marsh is one of them.

(Pix courtesy Shantha Jayaweera)

By Risidra Mendis