International study on Artemia
LXIII. Field study of the Artemia urmiana (Günther,
1890) population in Lake Urmiah, Iran
G. Van Stappen, G. Fayazi, P. Sorgeloos-2001
Hydrobiologia, 466(1-3): 133-143
Abstract:
Lake Urmiah is a large (total surface 4750–6100
km2 in recent times) thalassohaline hypersaline lake (150–180
g l-1 in the period 1994–1996),
located in northwestern Iran. It is the habitat of the endemic Artemia
urmiana. Over the period July 1994–January
1996 a sampling campaign was organized: 36 fixed sampling stations,
distributed over the entire lake's area, were sampled weekly to determine
water temperature, salinity and transparency. At each occasion a filter net
was dragged over a distance of 400 m in the superficial water layer to
assess the density and composition of the Artemia population. A
more limited sampling campaign focused on the annual fluctuations in
chlorophyll concentration and on the reproductive behaviour of the brine
shrimp population. Several stages of brine shrimp survived during winter
months (water temperature 3°C) at low
densities. Compared to available data for the Great Salt Lake, USA, Lake
Urmiah shows a low algal biomass and overall low Artemia density.
The increasing grazing pressure of the developing brine shrimp population in
spring seems to prevent the phytoplankton from reaching high blooming
concentrations, and oviparity is the dominant reproductive mode throughout
the reproductive season.
(Laboratory of
Aquaculture &
Artemia Reference Center, University of Ghent, Rozier 44, B-9000 Ghent,
Belgium, tel: +32/9/264.37.54, fax: +32/9/264.41.93,
e-mail: gilbert.vanstappen@rug.ac.be)