Climate change in Northern Mongolia presents extremely serious ecological and economic risks. Air temperatures have already risen by 1.7°C over the past 40 years. In recent years, hot dry summers followed by harsh winters have resulted in massive  livestock die-offs called zuds. In the zud of 2009-2010, an estimated 8 million head of livestock died, pushing many of their owners into poverty and driving migration from rural areas into the city. Mongolia’s aquatic ecosystems and growing freshwater fisheries may also be at risk from climate change. Lake Hovsgol is an ancient rift lake that contains nearly 70 percent of Mongolia’s fresh water. The “Blue Pearl” is also a premier destination within Mongolia, both for Mongolians and for foreign tourists. Despite Lake Hovsgol’s importance and designation as a national park, it is threatened by climate change, rapid unplanned development, and poorly enforced conservation laws. Given the lack of adequate monitoring, it is difficult to determine the extent to which these stressors have already altered the lake’s ecology.

 

Over the last decade, the recreational fishery for taimen (Hucho taimen, the world’s largest salmonid) has been growing rapidly, bringing much needed income to rural areas. An illegal commercial fishery for the endemic Hovsgol grayling (Thymallus nigrescens) also appears to be growing, although data are scarce. Taimen and Hovsgol grayling are endangered species, and the combined impacts of fishing and climate change on their populations are poorly understood. Salmonids like taimen and grayling are extremely sensitive to warm water and associated low oxygen levels, and both species in Mongolia are at the southern edge of their range where climate change impacts are likely to be most strongly felt. This project aims to improve the understanding of links between climate and the ability of Lake Hovsgol and its major outflow, the Eg River, to support important and endangered fish species. A strong understanding of Mongolia’s lakes and rivers, by well-trained Mongolian aquatic scientists, will be crucial if mining, tourist development, and fisheries are to be sustainable in a changing world.

 

 

During the first quarter of 2013, Dr. Bud and her U.S. collaborator Dr. Jensen worked on analyzing data collected during the summer and fall 2012 expeditions. These data include temperature records from loggers set in Lake Hovsgol and the Eg and Uur Rivers, fish morphometric information collected primarily in Lake Hovsgol, and bioenergetic data collected in fall 2012 at the Eg and Uur Rivers. The team has initiated collaborations with other scientists in the United States (Dr. Clyde Goulden of Drexel University and Dr. Simon Hook of NASA) and Mongolia (Dr. Bazartseren Boldgiv). The latter collaboration is aimed at combining water temperature data with in situ air temperature measurements at the Hatgal meteorological station, located near the southern end of Lake Hovsgol, and at Dr. Boldgiv’s research site on the lake’s eastern shore. Dr. Goulden is contributing water temperature data from sampling conducted by his group in the 1990s, while Dr. Hook is contributing surface water temperature estimates derived from satellite remote sensing. Preliminary analysis of the water temperature data from Lake Hovsgol shows a presumably rare upwelling event in which cold bottom waters at a 50-meter-deep site on the western shore were brought to the surface. The team is currently analyzing Dr. Boldgiv’s wind speed data to see if this upwelling event could have been caused by unusually strong winds. The project team also focused on data compilation and analysis, as well as planning for the 2013 field season and identifying and pricing equipment to be purchased. Planning activities have included identifying suitable student and park ranger participants and discussing project plans with them; reserving a research vessel; and coordinating tentative dates for the upcoming joint Mongolian-U.S. expedition planned for the summer of 2013.