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Abundance and distribution of Veneridae family in the Hendijan coast, Khuzestan province (Persian Gulf) were studied in a period from summer 2005 to spring 2006. Sampling was done seasonally with vanveen grab from 5 stations. Stations were located 0.5 mile apart and samples were collected from approximately 8 m depth. In this study 5 species of Veneridae were identified: Circenita callipyga, Gafrarium pectinatum, Bassina calophylla, Paphia gallus and Paphia textile. The abundance and percentage of frequency for each species were measured. The highest frequency of occurrence was observed in Circenita callipyga with ratio 88.69% and abundance 8668 No m-2 and other species had low ratio. Juveniles had 9.93% in ratio and 971 No m-2 in abundance. The effect of temperature, salinity and particle size of sediment as three main environmental parameters on benthos frequency were investigated. Significant relation was found in frequency and particle size between 63-125 micrometer but there was no significant relation between frequency and other factors. Diversity indices showed poor diversity of Venerid population in the north of the Persian Gulf.

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Diazinon is commonly used for pest control in the agricultural fields surrounding freshwater reservoirs. So this study was conducted to determine the sub-lethal toxicity of this organophosphorous pesticide, contaminating aquatic ecosystems as a pollutant, and its effects on histopathology of testis and ovaries common carp, Cyprinus carpio. Diazinon was applied at sub-lethal concentrations of 60 µg/l and 120 µg/l at 30 days. The histhopathological effects of diazinon on testis and ovaries tissues of Cyprinus carpio were determined by light microscopy. In this study, negative effect of diazinon on the testicular and ovarian tissues of common carp is investigated. The degeneration of seminiferous tubules, atrophy and vacuolation in testicular tissues are most important changes observed in treated fish by diazinon. The atretic oocyte and degenerative cell phagocytize in ovarian tissues of fish exposed to diazinon were seen. Histopathological changes were significantly increased related with increasing diazinon concentrations.

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In this study, reproductiv cycle, gonadosomatic Index and maturity of klunzingeri was studied in the Eastern Coast of the Khuzestan province. Sampling took place during a period from April 2004 to March 2005. A total of 1880 fish specimens were studied morphologically and 974 of them were investigated in the labratory. The average values of lenght and weight were measured for both sex (19/11±1/49 cm, 73/43±13/71gr and 17/97±1/15cm, 85/91±20/95 gr) for male and female respectively. The Maximum values of GSI were recorded in November for both sex and reached to the minimum levels in July for femele and in Agest and September for male. The maturity lenght of this species was measured. The maturity lenght of this species was measured 14.5 cm for both sex. According to the cyclic changes in GSI, the spawning was considered to take place in November and Decemer.

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In this research, spirulina was imported form Indonesia to Iran. After microscopic evaluation by identification key according to appearance, diameter, length of cell and trichome in liquid and semi-solid media, species had been known as Arthrospira platensis. This microalga has been cultured in laboratory condition throughout 40 days and concentration of cell was calculated in different periods. At first, it was cultured in 350ml containers after that it has been cultured under green house condition and transferred in 1.5 l containers. The best growth showed in 18 day period in 300 ml container that was prepared with 20ml of Spirulina inoculums with 17500 cell/ml concentration, florescent light (40w) with 16hour light and aeration for 24 hours. In this condition concentration of cell was counted by neobar lam 127500 cell/ml. J treatment among 1.5 l containers had maximum concentration about 400000cell/ml. This microalga has been cultured in outdoor with greenhouse condition and when the size and concentration of spirulina was suitable then biomass was harvested and produced dry product of spirulina.

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This experiment was conducted in earthen ponds of the Azadegan fish culture site, Ahvaz, Iran. In this method (two - crop at year) in first stage pond were stocked at rate of 1000 silver carp fingerlings (92. 30±2.77 g), 1000 common carp (10.47±2.64g), 200 grass carp (101.43±14.92g), 200 bighead carp (107.17±14.26g) per hec. in second stage, pond were stocked at rate of 1000 silver carp fingerlings (130.80±5.77 g), 1200 common carp (9.57±2.45g), 200 grass carp (118.92±12.95g), 200 bighead carp (161.13±9.43g) per hec. In common method (one crop at year) pond were stocked at rate of 1200 silver carp fingerlings (71.23±2.62g), 1200 common carp (2±0.5g), 200 grass carp (75.07±4.42g), 200 bighead carp (79.70±3.21g) per hec. After culturing period in both systems (130, 215, 332 days) crop were harvested. The results showed that production of two-crop method was 7151 Kg/ha and in the other method was 6516 Kg/ha. The profits of two-crop system was 77196000 rials(≈8345 US$) while in the other method (one crop in year) was 37008000 rials(≈4000 US$).

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This research was done in 4 stations in shadegan wetland and one station in jarrahy river during 2008-2009. Monthly sampling was carried out by using of quadrate (625 cm2/area) and Peterson grab(225cm2).Total organic matter and grain size were measured by ignition loss method and sieve series method respectively. Totally 14 groups of macrobenthic were identified .The individual of Chironomidae family were the most abundant group (91 %) and the Oligocheats was the second group (4%).according to benthic frequency the highest and the lowest abundanancy was observed in Attaish and Shadegan out let station (in Doragh creek) respectively .The result of TOM and grain size analysis showed that in all station more than 78% silt-clay were observed and the range of TOM percentage was (3.14-18.17).The highest and the lowest value were measured in Muleh and Gar Gar stations respectively. The comparing of benthic animals abundancy in recent study and previous study in 1996-1997,showed that the macrobenthic was obviously more abundancy in Attaish and Rogbeh stations in the recent study. This increasing can be caused by high abundancy of the individual of Chironomidae family as the tolerant animals group, in disturbed and polluted condition. Also the range of diversity indices (H´) was from 37% to 99% that showed unstable and unfavorable ecological condition.

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Abundance and distribution of Veneridae family in the Hendijan coast, Khuzestan province (Persian Gulf) were studied in a period from summer 2005 to spring 2006. Sampling was done seasonally with vanveen grab from 5 stations. Stations were located 0.5 mile apart and samples were collected from approximately 8 m depth . In this study 5 species of Veneridae were identified: Circenita callipyga, Gafrarium pectinatum, Bassina calophylla, Paphia gallus and Paphia textile. The abundance and percentage of frequency for each species were measured . The highest frequency of occurrence was observed in Circenita callipyga with ratio 88.69% and abundance 8668 No m-2 and other species had low ratio. Juveniles had 9.93% in ratio and 971 No m-2 in abundance. The effect of temperature, salinity and particle size of sediment as three main environmental parameters on benthos frequency were investigated. Significant relation was found in frequency and particle size between 63-125 micrometer but there was no significant relation between frequency and other factors. Diversity indices showed poor diversity of Venerid population in the north of the Persian Gulf.

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Food diet of Mudiskipper Fishwas considered seasonally ,in samaeily creek of mahshahr ,from Creek System of Musa Bayduring an Annual duration from Summer 2008 to the Spring 2009.Fishes were captured using Sachook and air gun.After fish caught and incision of biological samples ,the identification of food types of the gut contents were taken into consideration.the results of such biological analysis from 85 mudskipper individuals belonged to Periophthalmodon schlosseri species,with Average Total Body Length of:10.07±0.27cm ,the Average weight of :8.75 ±0.67 gr, Average ( RLG) Index of Intestine being at:0.96±0.0.04 (0.52-1.45).Therefore this species is considered as carnivorus ,where according to gut content Analysis,the main food diet of this species during the study time has been crabs,where miscellaneous food intake according to their percentage of occurrence respectivey were shells,insect and the least accidental intake was prawn.

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In this study frequency and composition of plankton in Shadegan wetland was carried out in 5 stations during 2007-2008. Genus qualitative identification and their composition and quantitative frequency aspect were studied (for phytoplankton chlorophyll a). Frequency of total 42 genus phytoplankton in 4 classes Bacilariophyceae (Diatom), Cyanophyceae, Chlorophyceae and Dinophyceae are 69.4, 22.22, 10.15 and 5.16 percent respectively and Diatoms are most dominant. In which Cyclotella and Nitzschia genus have the most abundance. In this manner, Frequency of total 24 genus zooplankton 4 groups Rotifera, Copepoda, Protozoa and Cladocera that are 80.47, 17.30, 2 and 0.23 percent respectively and Rotifers are most dominant. Phytoplankton has two frequency peak: first in the summer and the second with less in the early fall. Rogbh and Etysh have the most diversity in all of the stations. Mean annual primary production are 1.67 gC/m²/d and maximum and minimum are 4.67 and 0.50 respectively. Absence of indicator species that eutrohic lakes such as Peridinium and Ceratium and none blooms of Cyanophyceae, are rejected the existence of conditions eutrophic. Other evidence, including presence macrophyta, the low water turbidity and high plankton diversity is an indicator of the quality of all of which are relatively natural wetlands. New input waste water agricultural to wetlands can first increase primary production by high nutrients and according occurrence of chaos theory and environmental stress, stress factors, first increase species diversity and in continuation status diversity decreases .

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This investigation was carried out monthly between September 2005 to October 2006 with shrimp trawl that had mesh size of 24 mm in order to recognition, estimate the frequency and distribution of Penaeidae shrimp in Mahshahr creeks (Darvish, Doragh, Ghazaleh,Ghanam, Bi had, Patil and Zangi). A total of 1925 individuals which belonged to 3 species of Penaeidae family were captured. Their mixture composed of Metapenaeus affinis with 60.62%, Parapenaeopsis stylifera with 37.73%, and Penaeus semisulcatus with 6.65%. In this spescies female sex had more frequency than male. Maximum abundant also existed in June to August 2006 . Ghazleh creek had maximum abundant of shrimps . All species were in juvenile and pre-adult stages (had length range 44-129mm). However, based on ANOVA analysis, we observed significant differences between monthly frequency of shrimps (p≤0.05). Frequency of shrimps was higher in warm month.

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Polycyclic Aromatic Hydrocarbons (PAHs) are stable organic compounds that their carcinogenic properties have been proved. This components enter to the organisms body throught food chain and affect the consumers adversely. This study was conducted in order to consider the effect of water soluble fraction of crude oil on the accumulation of PAHs in muscle tissue of Pseudorhombus elevatus of The Persian Gulf. It was performed in spring 2005 in the ecology research center of The Persian Gulf. Two solutions with 0ppm and 12ppm dosages of crude oil were prepared with Anderson method and seawater. Then 24 fish from this species that were caught randomly from 6 stations of The Persian Gulf were exposed to 0ppm and 12ppm dosages of crude oil for 8 days in long-term bioassay examination. After 8 days exposed fish were freezed and packed seprately and sent to the laboratory for determination of PAHs accumulated in their muscle. PAHs measurment was done with GC-FID model varian 3400. In this research, the amount of each compound of PAHs was detected. Then total PAHs in each dosage was calculated seprately. The result of data analysis shows that the mean accumulation amounts of PAHs ( STD) in tissues of testifier Pseudorhombus elevatus was 929.66  2.51 ppb. Also the mean accumulation amounts of PAHs ( STD) in tissues of Pseudorhombus elevatus which were exposed to 12 ppm dosage of crude oil was 3843  13.52 ppb. According to T-test test we concluded that there is a significant difference (p<0.05) between two mentioned dosages of crude oil from their accumulation point of view in muscle tissues of this species. In other words exposing fish to 12ppm of crude oil can increase the accumulation of PAHs in comparition with testifier fish. On the other hand, the high amount of PAHs in the testifier fishes is due to pollution of The Persian gulf.

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Feeding of Shah – koolee which is one of the economical and popular fish in the northern part of Iran was studied in the area of the Sefidrood river. Carry out this research, 539fish were cought at selected stations from the scashore estuary to Kisum From April to August 2000 Intestinal content of sixty eight speciment in different sizes was collected and after primary biometry, their gastrointestinal system was removed and studied. Relative gut length (R.L.G) was 0.74 and the special charactristics showed that the main food of Shemaya is zooplankton. The vacuity index (C.V) was 23.5 percent Which proves that Shemaya is among greedy fishes. Instestinal examinations of Shan – koolee Shows that Three phytoplanktonal order including Crysophyta, Chlorophyta and Cyanophyta and two zooplankton order including Copepoda and Cladocera were the major food items consumed by this fish in Sefidrood river. In addition, some different organisms bigger than phytoplankton and zooplankton such as Chironmidae larvae and Gomphonaema were in its diet. Studies of Shah-koolee migration in Sefidrood river shows that spawning is more important than feeding.