Monitoring of Artemia stocks in Urmia lake

Abstract

Monitoring of Artemia Stock in Urmia Lake ( with less than 5 billion m^3 ), between 2001-2003 in order to survey of Artemia population dynamic and some water abiotic factors such as WT , salinity and transparency using Thermometer, refrectometer and sechi disk, were done montly. Phytoplankton with Rotner sampling device and Artemia (different life stages) were sampled by planktonic net from 7 suit stations(3 layers, surface, 2.5 and 5 meters with 3 replications) which were selected from 12 sites used in previous Artemia stock assessment project Graphs drawed by excell sotware in different layers , months and sparation between north and southern parts of the Lake(±SD ,SE), showed WT fluctuated from 3 degree centigarade in December 2001 to 29 degree in November 2003 with the same changes in different layers. Salinities from 290 ppt in Autumn 2001 to 340 ppt in summer of 2003 increased. Northern part of the lake had higher salinity than the southern. There were not any differences between different layers in salinity changes, transparency were as the dept of water and there were no any phytoplankton in samples. Number of cysts in surface was 1933±850, in northern part 1782±998 and in southern 2032±1061. At 2.5 meter dept 327±110T 229±107 and 363±110 cysts wer counted respectively. At 5 meter dept there were 419±124, 181±62 and 282±65. Other numbers of biological stages were counted as cysts in thre layers, nort and southern parts of the lake. Data concluded that cysts and biomass were dominated in southern part but at surface and 2.5 meter dept respectivel.