Fish in the Mekong River are in trouble and scientists from NSW and Queensland are travelling to Laos to help develop fish ladders so they can get past barriers in the river.

"The two-year project, funded by the Australian Centre for International Agricultural Research (www.aciar.gov.au), is allowing NSW and Queensland Department of Primary Industries (DPI) scientists to help Laos scientists develop techniques to help fish migrate past dams and weirs and rehabilitate declining fisheries.

"The grant involves these scientists working closely with researchers in Laos from the National University of Lao and the Living Aquatic Resources Research Centre," NSW DPI research scientist at Narrandera Fisheries Centre, Dr Lee Baumgartner, said.

Dr Lee Baumgartner said the Mekong River was home to more than 1000 native fish species and was one of the most diverse river systems in the world, containing unique freshwater dolphins, stingrays and large freshwater catfish.

"However, recent development has seen the construction of thousands of dams and weirs, which have obstructed fish migrations throughout the Mekong Basin.

"Fish are a major source of food and protein for communities along the Mekong, but in some areas dams and weirs have caused fish to decline so rapidly that river communities are starting to suffer," he said.

The ACIAR project will seek to determine the swimming ability of migratory fish by constructing an experimental fishway; a channel that allows fish to migrate around or through an obstruction.

Dr Baumgartner said fishways have been widely constructed in Australia and are very effective at providing migration pathways for native fish. However, in Laos there are currently no functional fishways.

Scientists will initially install the experimental fishway on a known migration barrier and use it to determine the maximum swimming speed of Mekong River fish. Once this is known the team will build and install a permanent fish ladder based on the parameters determined in these experiments.

The fish ladder will provide a pathway for migrating fish to continue their upstream migrations. If successful, these structures will then be built in other areas of Laos where fish communities are in decline.

Dr Baumgartner said the research would also have direct application in Australia, because many fish families found in the Mekong also exist here.

"Although most Australian fishways are successful for large fish species, scientists have had significant trouble assisting the migrations of very small fish species. Small species are very abundant in the Mekong River, so we hope information generated from the research in Laos will allow the construction of more efficient fishways in Australia," he said.

"The Mekong also has a number of species that are highlighted as potential invasion risks to Australia. Australia scientists will closely study these species and gather important inform-ation to help develop control programs if these fish should inadvertently arrive in our rivers."

Photo available from sarahc@sf.nsw.gov.au

More information

Fishways

Staff profile of Lee Baumgartner

Media contact: Sarah Chester (02) 6036 2110 or 0417 207 669