The Ngao River, which is part of the Salween River basin, is largely inhabited by ethnic Karen communities who rely on river-derived foods like fish and snails and rely in the river for drinking, bathing, and irrigating crops. The local villages along the Ngao River communities have created a network of community-run conservation zones in response to suspected declines in fish abundance. These conservation zones are protected from any harvest of aquatic life throughout the year, although some catch-and-release angling is allowed by visitors for a fee.
Dr. Aaron Koning of the Atkinson Sustainability Center Fellow, Cornell University, has been working in northern Thailand for several years in the Ngao river watershed. His research has encompassed many aspects of river health, including the effect of changing agricultural practices might have on algal production in Thai rivers, how the consumption of algae and aquatic insects by fish can affect community structure and ecosystem processes, and the potential for small, community-based conservation reserves to protect aquatic biodiversity and support local food security. Dr. Koning has documented that the protected zones have been highly effective and that there are substantially more fish in conservation zones compared to the non-protected areas.
The villages in this basin rely heavily on these fish as a food source, however, very little is known about the basic life history many of the fish in the Ngao river basin. Even among the Mahseer that are found in this region, it is suspected that there may be multiple species.
During the International Mahseer Conference (Paro, Bhutan Dec 2-8, 2018), Aaron learned of the success in Bhutan with tracking Mahseer and the valuable knowledge that has been gained on fish movement there. With the help and support from several partners, including Dr. Apinun Suvarnaraksha from Meajo University, Thailand, and the Fisheries Conservation Foundation, Aaron secured the equipment and funding to begin a telemetry study on the mahseer species in the Ngao river.
The goal of this current project is to learn how Mahseer move among these reserves throughout the year. Fish will be tracked to document their migration patterns for spawning, as well as how they use the conservation zones. This knowledge will aid in understanding the impacts of the current conservation zones as well future sustainable management actions for Mahseer populations throughout the Ngao basin.
Each fish that has been implanted with a radio-transmitter will be detected when it swims near a receiver station. Fish can also be detected with a manual tracker, shown here. This allows researchers to travel along the river and see if they can find any of the tagged fish that would be swimming or holding in an area between receivers.
During the trip, Dr. Zeb Hogan from National Geographic and the host of the “Monster Fish” TV show, and Stefan Lovgren, a National Geographic photographer, joined the team while they were on the river. Stefan prepared a story the effects of community conservation, including the Thailand example. His article can be found here: https://www.nationalgeographic.com/environment/2019/04/sanctuaries-help-fish-recover-southeast-asia/