Detecting the Spatial Distribution of Artemia at Urmiea Lake
M. Ahadnejad Reveshty
University of Zanjan, Dept. of Geography
Email: mo_ahadnejad@yahoo.com
Introduction
Artemia is an aquatic crustacean belonging to the subclass of ostracoda, characterized by a bivalve, generally calcified carapace with a hinge along the dorsal margin. It is a fine benthic marine fauna living in saline water, called Artemia Cysts (Brine Shrimp Eggs). Because many ostracoda species have ecological limitations controlled by temperature, salinity, oxygen, food and other factors, they can provide an important tool for pale-oceanographic reconstruction. Artemia is a marine fauna with a very vast geographic extent throughout the world. Presently over 500 different species of artemia have been recognized in 500 different geographic locations. Presently artemia in Iran has been found in 18 different geographic locations in saline lakes and lagoons but Urmia Lake is known as the largest habitat for this fauna. Due to Artemia’s nutritious values it is used as a significant food source for most aquatic fauna as shrimps, caviars, and shells. Annual consumption of Artemia cyst in world aquaculture centers increased from 60 tones in 1980 to 2000 tones in year 1994.
Artemia is a collection of certain sibling species as well as super species differing from each other due to their reproductive isolation. In general two different type of artemia naming bisexual artemia and parthenogentic artemia breed in two different ways as ovoviviparous and oviparous during a year.
Previous Work & Necessity of Research
The first written report concerning the Urmia Artemia was prepared in 1899 by Ghanter. In 1976 another research presented by Clark & Bowen relating Artemia and its breeding condition in Urmia Lake. An extensive research conducted by Dr. Azari Takami in 1992 revealed that Urmia Artemia is certain species unique for Urmia Lake and is different from the others; therefore he named it as Artemia Urmiana. In 2002 concurrent with the establishment of The Artemia Research Center in University of Urmia a lot of researches are conducted in this center. Besides that artemia farming under laboratory conditions is also being experimented in this center.
Temporal and spatial distribution of artemia has been discussed so far using sampling technique while other enhancement techniques as remote sensing and satellite data has not been seriously considered .The present research mainly focuses on enhancement techniques for artemia detection in Urmia Lake using land sat TM data and image processing techniques.
Study Area
Urmia Lake as the largest habitat for artemia and the largest water body in Iranian plateau is located between two major provinces of East Azarbaijan and west Azarbaijan. The lake is bounded between 37 4 - 38 17 latitudes and 45 13 - 46 longitudes. The lake covers an area between 4000- 6000 km2 averaging around 5000 km2. 20 permanent and seasonal rivers as well as a few submarine streams and springs feed the lake. Average salinity of the lake ranges between 220- 300 mg/lit depending upon temporal and spatial conditions .Due to the ecological heritage of Urmia Lake it is recorded as a protected habitat in the world by the United Nations.
Biological Characteristics of Artemia Urmia
Urmia Artemia is one of the seven polygamy species (male and female) yet recognized in the world. The artemia feeds alga and other saprogenic material in the lake. Table 1 compares biometric indices of Artemia Urmiana (male and female) with other artemia throughout the world.
|
Biometric indices/Location | Tanzania | China/ Yanshing lake | Ghazaghestan | Artemia Great salt lake(USA) | Urmia Artemia |
|
Male Body | length/mm | 8.86 | 10.44 | 10.16 | 9.22 | 12.47 |
|
Male Body | length/mm | 10.99 | 12.53 | 11.43 | 12.51 | 16.45 |