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Mekong River and the Iconic Giant Catfish
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During the past few years FISHBIO has been researching the structure and characteristics of fisheries in villages in the Mekong River basin to assess their significance to the local communities. As we have learned from past experiences, some of the most cost effective fish sampling can be done in local fish markets. The fish markets make it possible to sample many more species of fish without spending the time and effort to capture them. This technique can be very effective when trying to determine the presence/absence of species over a large spatial scale, or identifying undocumented species in the Mekong River basin.
Perhaps the most iconic species of the Mekong River is the Mekong giant catfish (Pangasianodon gigas). Giant catfish are highly migratory fish, traveling hundreds of miles upriver to spawn; however, dams to the north have isolated much of their spawning habitat. Known as the world's largest freshwater fish, Mekong giant catfish are capable of reaching almost 10 feet (3 meters) in length and an excess of 660 pounds (300 kilograms). Over the past century their population has dropped by 80 percent due to overfishing and loss of spawning habitat (IUCN Red List). International efforts are under way to save this iconic species. It is now illegal to harvest wild giant catfish in Thailand, Lao PDR, and Cambodia, however enforcement is nearly impossible. On a recent trip we spotted a suspected Mekong giant catfish (pictured above) at a morning market in Luang Prabang, Laos PDR. We recorded as much information about the specimen as possible and collected a tissue sample for DNA analysis.
The Mekong River Basin supports the largest freshwater fishery in the world, with harvests over 2.6 million metric tons per year and a great deal of subsistence fishing. Concerns over the wild fisheries and food security in the Mekong River basin have been on the rise in recent years due to a better understanding of the impacts of climate change on the basin, and a growing movement to increase the number of hydroelectric dams. There are currently 13 dams that have either been built, or are under construction, and another 47 are said to be in the works or under development. Some of the proposed dams may further limit the Mekong catfish's access to spawning habitat. Due to the high fish species diversity and the degree to which people rely on these fish as protein, altering the distributions of fish has the potential to affect livelihoods and food security for millions of people. Given the uncertain future of hydrology in the basin, there is an urgent need for informative studies on fish species distribution and migration patterns in the Mekong River basin.
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IN THE NEWS: Recent stories you might have missed...
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Officials predict good salmon fishing season off California coast
Press Democrat
Federal regulators badly overestimated how many chinook salmon would return to the Sacramento River last fall, a key criteria used to set the sport and commercial fishing season. Nevertheless, scientists expect there will be plenty of salmon to allow fishing off of California and Oregon, officials said. "Despite our shortcomings in forecasting, there will be a bunch of fish around next year," said Chuck Tracy, spokesman for the Pacific Fishery Management Council in Portland, Ore. "It will probably provide a pretty good opportunity for most fisheries."
Read more >
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Army Corps ordered to move fish above Yuba River dams
Sacramento Bee
Federal wildlife officials have ordered the U.S. Army Corps of Engineers to ensure that salmon, steelhead and sturgeon are able to surmount its two dams on the Yuba River. The National Marine Fisheries Service, in a biological opinion released late Wednesday, concludes that Daguerre Point and Englebright dams threaten the survival of the fish species. The order does not require removal of the dams, but that is one potential outcome. The Corps is required by March 1, 2014, to start an interim program to move fish around the dams using a "trap and transport" system, likely involving water trucks... Read more >
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Calif. delta tunnel plan would increase pumping
San Francisco Chronicle
The amount of water pumped out of the Sacramento-San Joaquin River Delta would significantly increase and some species would be harmed if massive tunnels are built to move water around the fragile ecosystem, according to thousands of pages of documents released by state officials Wednesday.
Additionally, more than 110,000 acres of fish and wildlife habitat would be created in the delta, representing the largest habitat restoration in state history. Officials stressed that the plan is preliminary and that they expect significant changes before it becomes final... Read more >
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A Bold Plan to Reshape the Central Valley Flood Plain
Bay Citizen
Jacob Katz stood shin-deep in a flooded rice paddy that is often dried out at this time of year. He thrust his hand into a writhing mass of baby salmon in his net and plucked three of the silver fry from the wind-whipped water's surface. In late January, five acres of this farmland in Yolo County was flooded and stocked with thousands of weeks-old Chinook salmon. It was the beginning of a three-year experiment that conservationists and government officials hope will provide scientific data to help guide a sweeping transformation of riverfront lands throughout the Central Valley, California's prolific farming region... Read more >
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Expect Large Numbers Of Fall Chinook Returning To The Columbia
Columbia Basin Bulletin
Fishery officials predict a return to the mouth of the Columbia River this year of 353,500 adult "upriver bright" fall chinook salmon, a total that would be the fourth largest on a record dating back to 1964. Larger totals were recorded, just barely in 2003 and 2004, and by a total of 420,000 in 1987, according to data compiled in the July 2011 Fall Joint Staff Report compiled by the Oregon and Washington departments of fish and wildlife. The estimated URB return to the Columbia last year was 325,100 fish... Read more >
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Thailand pushes ahead with Xayaburi dam project
Asia Sentential
Over the opposition of environmental groups and the governments of other countries in the Mekong Basin, the Thai government is pushing ahead with the construction of the controversial Xayaburi Dam, environmentalists say.
Although the Cambodian and Vietnamese governments have expressed concerns about the dam and work was supposed to stop until further study has been completed, preliminary construction on the giant dam deep inside Laos, is continuing, according to International Rivers, which opposes the structure... Read more >
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