Artemia population changes on Urmia Lake

The dynamics of Artemia population of Urmia Lake was investigated to provide the technical information, which is necessary for sustainable management of Artemia in Urmia Lake. The study covers different aspects comprising of monthly estimation of Artemia biomass and cysts, annual evaporation of Lake water, average precipitation in catchment areas and also water turbidity in Urmia Lake, during the 2004-2007. Results showed dramatic decline in the Artemia population compared to the previous years, Reduction of average annual precipitation and increased water usage in Urmia Lake catchment area during last decade, has reduced the annual quantities of flowing waters to the Lake. Although the estimated trophic state index (TSI) which indicated the mesotrophic condition during the studied period, therefore, exceeding salinity to higher than the saturated level had adverse effects on phytoplankton growth. Furthermore, nutrient transfer by the rivers to the lake caused to produce of halophilic bacteria and other obtrusive protozoas which has created very unsuitable condition for Artemia grazing. These events confirm the role of salinity as a major environmental factor that affects Artemia resources in their natural habitats. It can be proposed that a method to manage the lake ecosystem and its Artemia population through construction dividers, such as dikes between the north and south parts of the lake to reduce the salinity at some parts of Urmia Lake will be applicable.

Iranian Fisheries Science Research Institute

Published