Prabath Monerawila in his fish shack. (Picture courtesy Aruna) Endemic varieties of inland fish
A Sri Lankan young man who owns a successful freshwater fish business says that inland fishery is a neglected area.
Prabath Monerawila, whose fish shack (malu lella), located in Panagoda, roughly 20 minutes from Colombo, is critical of the government’s lethargic attitude though there is an approved fund amounting to $184 million to develop the sector.
Speaking to Colombo-based Aruna daily newspaper, Prabath says that he has been selling fish for about ten years. Usually, he has around 15 varieties of freshwater in his shack every day., a rarity by any standard. Some popular fish varieties he has on offer face the threat of extinction from Sri Lanka’s rivers, lakes and swamps.
The endangered species include hunga (stinging catfish), magura (walking catfish – named for its ability to crawl on land to find food), aanda (eel), thelia (garfish), kawayiya (climbing perch), sidaya, pirinilaya, koraliya (green chromide), lula (striped snakehead) and freshwater shrimp.
The fish in high demand in Prabath’s shack is lula. A well-grown one is sold for Rs.800 a kilo. It is also a native of India, Pakistan, Bangladesh and some Southeast Asian countries.
His daily catch of fish comes from areas like Bolgoda lake, Wewala, Kahapola and Polgasowita. Supplies from Embilipitiya, Anuradhapura, Udawala, Padawiya, Mahakandarawa and Ulukkulama discontinued temporarily after the curfew resulting from the lockdown to contain the spread of Covid-19, and he hopes the supplies to resume soon.
According to a survey, 24 percent of Sri Lanka’s inland fish are endemic. These species are threatened with extinction. Others are depleted due to the interaction of deforestation, urbanization, gem mining, pesticides, exploitation, water diversions, and introductions of exotic species.
Methods proposed by experts to reverse the decline include captive breeding, better watershed management, translocation, and regulation of fisheries, especially that for aquarium fishes.
I remember joining a media trip in the 80s to Kalutara district where there was a government-funded project to develop freshwater fish as an attempt to develop a protein-rich diet in rural areas. During Prime Minister R. Premadasa’s government, almost every home in the area had a tank to breed varieties of freshwater fish, but mostly due to aggressive opposition from Buddhist priests, the project hit a roadblock.
The first exotic species of fish introduced to the low country inland waters was Tilapia Mosambica (Oreochromis mossambicus). This species bred profusely and its increasing availability led to the commercialization of inland fisheries.
Later another species of Tilipia was introduced. Three major varieties of Chinese carp and three Indian carps, which are now of particular importance in aquaculture, were also introduced. These fish were introduced for inland fisheries, mainly due to the low availability of protein for the rural people, especially in the dry zone.
Native fish resources are also threatened with the introduction of invasive species. Prabath says that an imported variety called Night Fish is destroying the local fish population. “It is ruining our native fish resources by consuming their eggs and the young.”
Of the 97 species assessed for Sri Lanka’s red list of threatened freshwater fishes, 61 are endemic to the Indian Ocean island. Of these, 12 are considered critically endangered, and ten vulnerable, according to a survey.
Prabath says freshwater fish is rich in nutrients than the sea fish and comes fresh without refrigeration. After the Kovid-19 many people have started to consume freshwater fish as researches have shown freshwater fish boost immunity, he adds. Mangrove jack fish (thambalaya), our biggest freshwater fish is facing extinction, he says.
In a separate interview with Mongabay website, a young Sri Lankan fish enthusiast, Pathum Madhusanka, says Thalangama Lake, an urban water body near Colombo, is plagued by at least two invasive predatory fish species that are contributing to the decline of the native aquatic life. These species are alligator gar, a native of North America and Clown Knifefish, a Southeast Asian fish.
There’s growing interest among fish breeders in Sri Lanka to cultivate “monster fish” — exotic, large, often carnivorous species — and alligator gars have become a popular fish in many Sri Lankan commercial aquariums to the detriment of inland species, says Madhusanka.
A list, compiled this year, recognizes alien invasive species as a big threat to the island’s freshwater fish. It identifies 30 such alien fish species in Sri Lanka’s natural freshwater habitats.
Another expert, Sampath Goonetillake says, “Not all the exotic fish released to the natural waterways can be listed as invasive.” For a fish to be considered invasive, it must directly impact native species by competing with them for resources or directly feeding on them.
“We also have observed species such as gouramis, zebras, platy fish in natural waterways that are still not considered invasive, though it is extremely important to keep a watchful eye over them,” Goonetillake said.
Sri Lanka banned imports of knifefish in 2003 and piranhas in 1998. Still, these kinds continue to be locally bred, and accidental releases remain a risk
Sri Lanka has over 103 river basins covering an area of 59,217 hectares but has no natural lakes. However, there are over 12,000 man-made lakes on the island. Tanks or reservoirs make up the main water bodies in the dry zone where freshwater fish breeding is flourishing. (Partly based on Aruna interview by Vajira Liyanage) – newstrails.com
