Publication Date:
2021-05-19
Description:
Anzali international wetland on the southern coast of the Caspian Sea has unique features and has a strategic role
in maintaining the ecological balance of animals and birds.Anzali wetland is one of the most
important ecosystem for fishes spawning and zooplankton groups are the first consumer in this ecosystem . he
aim of this study was to investigate the changes in fish communities in March(1393) to May(1394 ). Profiles of
chlorophyll a, total phosphorus, total nitrogen, oxygen saturation and brightness levels were used to assess the
degree of Eutrification wetland.Water analysis was conducted according to Standard Methods (APHA. 2005) .
Physical and chemical sampling was used for the Ruthner. Data from this study showed that the annual average
amount of total nitrogen was 0.519 ± 1.025 mg/l with minimum and maximum 3.187 and 0.279 mg/l
respectively. The annual average total phosphorus was 0.137mg/l , with minimum and maximum 0.11 and
0.752mg /l respectively. The annual average total concentration was 47.4µg/l, with minimum and maximum 0.11
and 0.752 µg /l respectively. Mean water temperature was 19.2± 7.4 with minimum and maximum 9.5 and 32 °
C respectively. The annual average total pH wa 8.12 ± 0.6, with minimum and maximum 0.11 and 0.752mg /l
respectively. The average annual amount of dissolved oxygen in all four regions of Anzali wetland was 2/6 ± 8/7
mg/l. According to the results, all areas except the western region of Anzali wetland (wetland Abkenar) are in
the range of hypertrophy of trophic levels Based on these results and considering trophic index, chlorophyll and
depth of transparency within the confines of hypertrophy in all areas of Anzali wetland. Generally all wetland
areas are within the confines of Trophic Based on the concentrations of nitrogen and dissolved oxygen.
Phytoplankton groups are very important producers in the anzali lagoon that have a significant role in the
quality of water and the need to be constantly study their sequence and density.The
surveywas conducted in six workstations March 1389-Feb 2012.Samples were taken for a liter of water with
polica( P.V.C ) and fixed with formalin to 4% ratio. Five ml of the sample after becoming homogeneous,
was sequestration for 24 hours in the laboratory and identified and counted by invert microscope. Based
on the results of this reviews 67 genus (22, 26, 9, 5, 1, 2, 1, and 1 genus respectively of
the Bacillariophyta, Chlorophyta, Cyanophyta branches, Cryptophyta, Euglenophyta Chrysophyta,
Pyrrophyta, the Xanthophyta) were identified. The results showed that the phytoplankton density was the
most in Sorkhankol and Komeh Aghajani stations with annual average of 24387483±5643414 and 20381250
± 5488084 per liter respectively.The Bacillariophyta ( particularly Cyclotella) was dominant in all of stations
but high density of blue green algae (Cyanophyta) in Komeh aghajani station from July to mid-October have
caused the annual average of these phylum is more than Bacillariophyta. In General, the average density of
phytoplankton was the highest in summer than other seasons and was the lowest value in the fall. The number
of the genus identified in this survay is less than previous studies. Compare this survey with the
last studies reviews shows that diversity is reduced in the current situation in the anzali than previous studies.
According to thestatistical analysis of the Kruskal Wallis, the density of phytoplankton had significant
differences in the different months, stations and seasons (p 〉0.05). phytoplankton phylums have significant
differences (p 〈 0.05) together.
Zooplankton status was evaluated in 10 stations of different areas of the Anzali wet land during March 2014 to
February2015. Sampling was done by tube (PVC) and passing through of 30 micron planktonic net. The
samples were identified and counted by invert microscope. A total of 72 Genus (1, 8, 4, 35, 15, 2, 1, 1, 1, 1,
3) of phylum Actinopoda, Rhizopoda, Ciliophora,, Rotatoria, Arthropoda, Gastrotricha, Mollusca, Tardigrada,
Nematoda, Porifera, Annelida) were identified. The results showed that the maximum and Minimum annual
average density of zooplankton was observed with 12383 ±9667 and 1539± 312 ind.lit-1 in Komeh Sheijan
station and West Wetlands Center station Respectively.The population was more in the summer than in other
season phylum of Rotatoria, Rhizopoda, Ciliophora and superclass Copepoda formed 59, 8,30 and 3 percent
of the density respectively. According to the results the populationof zooplankton is ncreased compared to past
studies. According to the statistical analysis Kruskal Wallis there were not significant
differences between density of zooplankton in different stations, months and seasons (p 〉 0.05), but significant
differences were found in between different phylum (p 〈 0.05).
Benthic macro invertebrates were studied as a pert of a main project titled” Studying the variation of Aquatic
communities in Anzali wetland”. 10 sampling site were determined and 3 replicate of sediments were monthly
collected using a 400cm2 Van veen grab during years 1393-4. One additional sediment sample were gathered to
determine TOM% and Grain Size. 14 macroinvertebrates taxa were identified as Chironomidae (Insecta,Diptera)
and Tubificidae(Annelida, Oligochaeta) were dominant.Maximum and minimum densities of
macroinvertebrateswere observed respectively in station 5 with 609±1119 n/m2
and station 1 with 93.32±27.92
n/m2
. Silt and clay constitute more than 85 percent of wetland bottom sediments with maximum of 93.2±27.92
percent in station 2 and minimum 72.21±27.92 in station 5. CCA analyse revealed no accordance of TOM% andsilt&clay% vectors with Tubificidae and total benthic fraquencies while Chironomidae frequency is in
accordance. Intensifying eutrification process in Anzali wetland has effected its biota as the benthic fauna are
almost limited in to most tolerant taxa which reflect the day after day increasing pollution Anzali lagoon.
Anzali lagoon was important as a rich source of fish some 50–60 years ago when the catch was dominated by
diadromous fish, mostly Rutilus frisii kutum.Endemic and exotic fish ecosystems are valuable fishes and
veryimportant for biodiversity, water indicators and source of protein in the human food supply. Fish
identification and stock assessment are very important for determination of age composition, diversity,
abundance, distribution andintroduce of commercial fishes and exploitation.
Sampling of this research was performed monthlyin 14 stations during 2013-2014. Catching fish, random
sampling, species counted, fixation, biometric, sex determination, sex maturation stages, age composition were
done according standard method . All data were recorded and analyzed in EXCEL and SPSS software.
During one year, 6764 number of fishes was caught. Then, they were counted and weighed. Fish number for
biometric and identification was 2775. The freshwater fishes of Anzali Lagoon comprise 25 species in 7 families
and 23 genus . the most diverse family being the Cyprinidae with 19 species 15 genus.The maximum length
was recorded 590 to 655 mm. Three species from exotic fishes similar to Carassius gibelio, Gambusia holbrooki
and Hemiculter leucisculus were constitutedthe highest density with 63/59 percent in Anzali lagoon. The fish
have been distributed at all sampling stations. Three species of big fishes similar to grass carp, Commoncarp and
pike were constituted 2.4 percent of the total catches. Commercial fishes were constituted 59 percent of the
caught fishes. Maximum number belonged to Carassius gibelio (1718 pieces) and Hemiculter leucisculus (1471
pieces). Sex ratio was done on 344 specimens with 93 male and 251 female.Sex ratio of Carassius gibelio (gold
fish) was determined 12 (male) to 133 (female). Age composition was measured between 1 to 13 years.
Maximum age of Carassius gibelio 5 years. Theoldest fish(13 years) was allocated to Cyprinus caprio species.
Statistical analysis between average total length, fork length and total weight in five districts of wetland area of
statistical significance between groups and within the group show at 5% level (p〈0.05).
Description:
Iranian Fisheries Science Research Institute
Description:
Published
Keywords:
Trophic index
;
Phytoplankton
;
Zooplankton Benthic Macroinvertebrates
;
Communities Fish
;
Carassius gibelio
;
Hemiculter leucisculus
;
Gambusia holbrooki
;
Aquatic
Repository Name:
AquaDocs
Type:
Report
,
Refereed
Format:
152pp.
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