An international team of scientists and fisheries experts was due to release more than 1,000 large fish at a fish sanctuary at Tonle Sap Lake in Siem Reap province from March 4-6. The operation aims to save some of the world’s largest and most endangered fish species, considered iconic symbols of Cambodia.
Zeb Hogan, an American research biologist at the University of Nevada, Reno, said the move was “the first step in an effort to restore populations of the largest freshwater fish in the Mekong”, according to a statement from March 4 press release of Wonders of the Mekong, a project funded by the United States Agency for International Development (USAID).
“Fish sanctuaries have proven to be an effective tool for protecting aquatic biodiversity and boosting fish biomass. It is one action, among many that are needed, to bring these species back from the brink of extinction,” said Hogan, who is also a principal investigator for Wonders of the Mekong.
Among the species to be released are the critically endangered Mekong giant catfish (Pangasianodon gigas), one catch of which currently holds the record for the world’s largest freshwater fish at 293kg, although the biologist French sailor Daniel Pauly and other experts have claimed that it can weigh up to 350 kg.
Also depicted is the endangered iridescent shark (Pangasianodon hypophthalmus), which is not a shark despite its name. The shark catfish species was once a regional staple, but its numbers have dwindled dramatically over the years.
Then there is the critically endangered giant barb (Catlocarpio siamensis), the largest species of carp in the world. It was designated as the national fish of the Kingdom in March 2005 by Royal Decree No. NS/RKT/0305/149 and is protected by Article 18, Chapter 2 of Royal Decree 33 on the management of the fisheries sector, adopted in March 1987.
“More than 1,000 individual fish will be released at a government-run fish sanctuary, Old Fishing Lot No. 4 in Tonle Sap Lake, a short drive and boat ride from Siem Reap town and the famous temples of Angkor Wat,” the statement said.
Ranging in size from 0.3 to 1.6m, most of the fish are juveniles that have been reared by the Fisheries Administration (FiA), in partnership with Wonders of the Mekong. “By tagging fish before release, researchers will have a unique opportunity to study animal survival, growth and movement,” he said.
Ngor Peng Bun, fish ecologist and dean of the Faculty of Fisheries Science at the Royal University of Agriculture, said in the statement: “The purpose of this event was to reintroduce endangered fish bred in captivity and follow their fate.
“We need to better understand the effectiveness of fish sanctuaries as a refuge for endangered fish; this posting today will inform future conservation practices and help us understand if these methods are effective in supporting the restoration of wild populations of these species,” he said.
The statement adds that as the largest lake in Southeast Asia by area – but not by volume – and home to more than 300 species of fish, Tonle Sap Lake “is a hotspot for water biodiversity. land and a UNESCO biosphere reserve”.
“Historically, it has served as a crucial nursery for endangered giant fish and for many other migratory fish populations in the Mekong basin. In recent years, these fish have come under increasing threat from upstream damming, overfishing and drought.
“To combat these threats to fish populations, a series of government-run fish sanctuaries and community conservation areas have been established in Tonle Sap Lake, forming one of the largest networks of aquatic conservation areas in the world,” he said.
FiA Director General Poum Sotha said in the statement: “The Cambodian government has taken steps to establish fish sanctuaries, protect core areas of the Tonle Sap Biosphere Reserve, and formalize community fishing and fisheries. associated reserves – these actions have made Cambodia an ideal place to initiate restoration of threatened fish stocks in the Mekong.
“Today is part of a multi-year effort to test the effectiveness of using Cambodia’s vast network of fish reserves for the reintroduction of captive-bred endangered fish back into the wild. The ultimate goal is to protect the fish until they grow big enough to reproduce, to support fisheries and biodiversity,” he said.