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Survey shows sharp dip in Lanka’s fish stocks
An independent ecosystem survey carried out on Sri Lanka’s coastal marine resources after forty years found that fish stocks have depleted rapidly to one fifth of what it was. This was due to several factors including overfishing and high level contamination by microplastics.
A Norwegian Research Vessel named “Dr. Fridtjof Nansen” completed the ecosystem survey around the coastal waters of Sri Lanka. The research was commissioned by the National Aquatic Resources Research and Development Agency (NARA) with the support of Norway’s Institute of Marine Research of Norway (IMR). The survey’s preliminary findings were released this week.
“In the last fisheries stock survey carried out from 1978-1980, it was estimated that seabed demersal fish resources were nearly 250,000 to 350,000 tons. However, our recent study found that they had depleted to 53,000 tons as overfishing, microplastics pollution and illegal fishing had a huge impact on the depleting marine resources,” NARA’s senior scientist Dr. Prabath Jayasinghe told the Sunday Times. He was the co-cruise leader of marine survey .
The survey also found that important habitats like estuaries, mangroves, and coral reefs were vulnerable to human activities such as local pollution and construction activities, and also from climate change and general heating. “The number of fishermen has been increasing since the 2004 tsunami, while aquaculture and tourism put pressure on coastal resources. The growing population of Sri Lanka has substantially increased the pressure,” he said.
The survey was part of the EAF-Nansen Programme implemented by the Food and Agriculture Organisation (FAO) in collaboration with Norway’s IMR and funded by the Norwegian Agency for Development Cooperation (Norad). “The total swept area biomass estimated from the survey was 53,000 tons, excluding jellyfish, garbage, coral debris and sponges that came up with the trawl. Looking at the biomass on the shelf (20-100 m depth) in the different regions of the North West coast gave the lowest biomass estimate of Sri Lanka of 967 tons. The highest biomass in the coastal zone was found on the shelf off Batticaloa with an estimate of 8173 tons,” the preliminary findings of the survey said.
Dr. Jayasinghe said that as the survey indicated, Eastern coastal waters consist of rich marine resources, including fish larva and baby fish, compared to other regions. Therefore, he said special steps needed to be taken to ensure the breeding stocks were maintained for sustainable marine harvest.
The preliminary findings also revealed that the waters around Sri Lanka were contaminated with microplastics, and the vast majority of which are in the secondary category, indicating that packaging material, industrial applications and fishing gear are major sources.
“The survey covered one season of the year, and the results, as such, are a snapshot. Microplastic particles were found throughout the survey area on all sampling stations. The highest concentrations were found in the seas off the North Western region of Sri Lanka. This region was highly polluted with microplastics, compared to other regions, while the northeast coast and the south coast showed the lowest number in the samples,” the report added.
Expressing severe concern over contamination by microplastics in Sri Lankan waters particularly in the Western costal sea, Dr Jayasinghe said immediate steps should be taken to stop further sea pollution which would destroy the rich marine resources left.