Publication Date:
2021-05-19
Description:
This study was done in 2008 on agricultural sewage for aquaculture in six stations. Two stations were in AhvazKhorramshahr
road near sugar cane plantation sewage in west Karoon, Two stations were in Ahvaz-Abadan road
in sugar cane plantation sewage in east Karoon and Azadegan sewage and two stations were in agricultural
sewage in the north of Ahvaz. Monthly Samplings of planktons, physical, chemical parameters were taken
during Aprile to March 2008. In addition seasonal sampling of benthic fauna and fish were carried out. Heavy
metal and toxic samples were done only one time during the study period. Measurement of some parameters
such as temperature and pH were done during sampling procedure and other parameters were measured in
laboratory based on standard methods. Heavy metal concentrations were measured with polarography and
voltammetry techniques and toxic substances were extracted and concentrated to determine the concentration of
them in water using GC device. For identifying phytoplanktons, 1 liter water from middle depth was sampled in
each station and 4% formalin was added. Zooplankton were sampled monthly using 55µ plankton net. Fish
samplings were done using cast net regarding regional condition, and sampling from benthic invertebrate of river
were done using Petersen grab with 15.5cm*15.5cm.
Results of water quality index (WQI) from Koushk Talaieh (station1), Artificial lake station (station 2) ,
Farabi(station 3), and Azadegan aquaculture sewage station (station4) showed that water quality is in group
four. WQS index was used for Maleh(station 5) and Pumping station ( 6 station) stations due to high levels of
salinity. The WQS results showed that water quality of these stations were moderate to low. Heavy metals in
water, the ordination is as follows:
Ni 〉 Zn 〉 Pb 〉 Cu 〉 Co 〉 Cd 〉 Hg
Mercury levels in all cases were less than the standard and all the elements have been somewhat less than
chronic toxicity level. The values of all studied metals are lower than the WHO limit. The results indicated that
chlorinated pesticides in all samples are at low level and they are at acceptable levels for aquaculture.
In this study, 34 genus of phytoplankton from Bacilariophyceae (diatoms), Cyanophyceae, Chlorophyceae and
Dinophyceae were present with 11, 8, 14 and one genus respectively and the percentage of frequencies were
respectively 37.64, 34.26, 23.24 and 4.87%. In general phytoplanktons of wastewater were in modest condition
for using in aquaculture.
In this study, about 1,000 samples of zooplankton in 6 stations were identified and counted during the year. The
high percentage of zooplankton were belonged to three groups of protozoa (mainly ciliates), Rotifer and
copepods were. The Rotifers with more than 90 percent frequency had the maximum prevalence. The dominant
rotifer species was Brachionus calciferous. Although in this study the dominant group of zooplanktons was
rotifers but the frequency is not high. Therefore we cannot call this circumstance as eutrophic condition,
however the growing trend of high food phenomenon has announced.
High benthic diversity was observed in Artificial lake wastewater station and Azadegan aquaculture sewage
station. The most frequent taxa were in Azadegan aquaculture sewage station during autumn and winter which
belonged to resistant Chironemidae larvae. In Koushk Talaieh, Farabi and Maleh stations, Chironemidae was
dominanted and in Pumping station Coleoptera was dominant group. Hilsenhoff index showed that most of
waste water stations were in poor to very poor condition, indicating that they were heavily contaminated. The
data analysis of macrobenthose data in wastewaters based on Satropi and biological value (Z) showed that
potential of fish production in Azadegan and artificial lake was high during the year. These two water sources
have suitable situation for potential production and biological value, therefore with special plans for culturing
low demand fish would be possible.
In this study, 7 fish species belongs to 7 genera from 4 families were collected. Freshwater and marine water
species was observed in the catch composition. According to the results of the four studied stations, Artificial
lake station and Farabi had the highest number of catch which mostly belonged to Acanttopetrus Latus and Liza
Abuo.
In general, based on biological parameters, such as zooplankton frequency, all stations had similar conditions but
in terms of phytoplankton, Azadegan aquaculture sewage station, Pumping stations and Farabi wastewater have
better condition for aquaculture. The FBI index showed that the artificial lake station and pumping station are
more suitable for aquaculture activity. Low demand fish is recommended for Azadegan aquaculture sewage
station. Artificial lake station had lower primary production but it is more suitable for aquaculture because of its
lower FBI index value. Most of the fish presence was in the artificial lake station and Farabi wastewater which
belonged to two predominant species of Acanttopetrus Latus and Liza Abuo.
In general, based on biological and non-biological parameters, artificial lake station in the west Karoon and
Azadegan aquaculture sewage station have better water quality than the other stations for aquaculture activities.
This requires management action and special schemes.
Description:
Iranian Fisheries Science Research Institute
Description:
Published
Keywords:
Agricultural
;
Brakish waters
;
Aquaculture
Repository Name:
AquaDocs
Type:
Report
,
Refereed
Format:
146pp.
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