Investigating on the possibility of increasing production in the Vahdat’s Dam in Eest Azarbaijan-Iran

The Lake Vahdat’s dam ( Kordkandi reservoir ) is located in 75 kilometers eastern of Tabriz in the East of Azerbaijan province With 37°59’ and 46°55’of latitude and attitude ,respectively. The purpose of the Dam is, storage of 6 million m3 of Ojan chai river for aquaculture use in the region. This study was carried out to investigate the possibility of increasing production in the Vahdat’s Dam and some biotic and abiotic factors of lake, such as physico-chemical properties of water, planktons, bentics, icthiology and characteristics of lake's bed were focused. Due to the area of the lake and proximity of the stations to each other, the entrance and estuary of the river as one station and lake as the second station were designated. In the case of phytoplankton, 42 genera were identified from 5 phylom, with 59% Cyanophyta and 21.5% for chlorophylls. For zooplankton, the highest frequency and variety related to the Rotatoria were 50.9% in the spring , which fed by fish and their larvae due to Omega-3 fatty acide. After Rotatoria, Ciliaphora were the most frequent. For Bentics, two sampling steps were carried out in the winter of 2007 and spring of 2008. The high biomass of Tubificidae was showed 0.034 gr ) 84.35/ m3)and 0.42 gr (143.7 /m2) in the winter of 2007 and spring of 2008, respectively. For Ictiology study, the high percentage frequency of fish related to Carassius auratus 42% and Hypophthalmichthys molitrix 38%. The biodiversity of fishes in the lake were confirmed by 12.5 % Alburnus hohenackeri , 87.5 % Carassius gibelio, Carassius auratus, Cyprinus carpio, Hemiculter leucisculus, Hypophthalmichthys molitrix, Hypophthalmichthys nobilis and Ctenopharyngodon idella. One of the most important environmental factors for aquaculture is temperature condition.Now, warm water fish were farmed in the behind of the Dam. The optimal temperature for these fish should be 15-30 ° C. According to the synoptic station of Bostanabad, the temperature of the study area of the Wahdat’s Dam is more than 15 ° C in the four months of the year (from June to September) which is suitable for aquaculture of Cyprinidae. The ice freeze days of the Bostanabad is about 124.6 days , anually. Therefore, the production of warm water fish has been faced with extreme temperature limitation in this lake and only in the short time of the year (mid-spring to end of summer) favorble condition exist for warm water fish farming. Based on the average area of the lake, the production capacity of Cilver Carp and Big head is estimated to be 2.34 and 1.73 tons,respectively.Therefore, assuming of average weight ( 15-20 gr) of fingerlings, 10000 and 7500 number of fingerling shoud be needed for silver carp and big head,repectively.accurding to decresing of variety of bentices founa,increasing of carp production or any other bentic feeder species is needed to manually feeding.In addition to the favorable chemical conditions of water for aquaculture and due to the limited volume of water during summer and suitable temprature of water in spring and fall can farm the fish in the top of the dam. In this regard (HDPEG) cages was established with 750 m3 and 800-1000 number of fish per cge ( 60% cilver carp, 20% big head, 20% carp)with 4.5 ton potential of production. The suitable dimensions of cage are 25-30 diameter, 5 height.There are ten cages fed by artificial food and natural production. Of course there is tourism potential opportunity which can think about that in this area.

Iranian Fisheries Science Research Institute

Published