فصلنامه بوم شناسی آبزیان
سال یازدهم شماره 2 (پیاپی 41، پاییز 1400)

The aim of this study was to evaluate the effect of trichlorfon on brain acetylcholinesterase, serum catalase enzymes, and gill and liver tissues of golden fish in the presence of vitamin C. The fish (10±0.5 g) were exposed to water-soluble trichlorfon for one month in four treatments as 1 control (no poison and vitamin), 2 (0.4 mg/l trichlorfon), 3 (0.4 mg/l trichlorfon and 200 mg/kg food vitamin C) and 4 (200 mg/kg food vitamin C), with 3 replicates. The results showed that trichlorfon significantly decreased the acetylcholinesterase activity compared to the control treatment, but the administration of vitamin C with this poison significantly (P˂0.05) increased the activity of this enzyme compared to the treatment without vitamin C. Trichlorfon did not significantly change the catalase activity compared to the control (P˃0.05). Trichlorofon caused necrosis, edema, shortness, slashing, and hyperplasia of secondary lamellas in the gills tissue of fish. This poison also caused bleeding, necrosis, and swelling of hepatocytes in the liver tissue, but because of the antioxidant properties of vitamin C, the administration of this vitamin reduced the severity of this tissue damage. According to the results, vitamin C with antioxidant properties improved enzymatic conditions and reduced the severity of gill and liver tissue damage caused by trichlorfon.

The present study was conducted to evaluate the effects of nanosilver coating on the reduction of fouling fish cages of rainbow trout in the Ayush dam of Khorramabad from winter 2016 to autumn 2016. The nets were applied for antibacterial properties according to the exhaustion method The samples were collected from net panels (0.0625 m2) that were attached to the PVC frame, located at a depth of one meter from the side of the fish culture cages, and wet weight was measured, then it was identified with valid authentication keys. In this study, three genera of green algae and diatom were identified. The analyses showed that Do, temperature, and pH were positively and significantly correlated with Tetrasporaceae, wet weight and algae cover percentage. The Seasonal nanosilver panels treatment was free of fouling. Nanosilver coating can provide at least three months of effective protection against biofouling conditions. Nanosilver occupies the interstices of the polyamide polymer chain and interacts strongly with single pair electrons of nitrogen hence a coordinated complex is formed.

This study evaluated the supply of fish in Golestan province by designing a questionnaire. For data analysis, Friedman, Kruskal Wallis, and Mann Whitney u test were used. The results showed that the per capita consumption of fish sellers was 62 kg. The total area of fish shops was 1431 square meters, and 225 people directly worked there. 44.4% of the total fish sales were retail sales. About 89% of fish was supplied by brokers through two types of supply chains for farmed fish and one chain for marine fish, each with 3 brokers levels. The average daily sales of any fish shop are between 45 and 530 kg. About 56% of the province's fish are exported, and 16.6% of marine fish and 34.4% of farmed fish are provided from outside the province. The sellers under the age of 35 believed that advertising is the main factor in selling the fish.  sellers with high school diplomas or lower education believed that fish quality and freshness are the main effective factors in sales, but sellers with education higher than high school diplomas believed the factors i.e., the amount of fish waste, promotion and fish size in sales. Sellers with more than 16 years of sales experience considered fish size as an important factor in sales. Therefore, in addition to optimizing the market facilities due to the export of fish to other provinces, it is necessary to pay attention to the needs and priorities of the province's residents according to the findings of Golestan fish sellers.

In the present study, the effect of different concentrations of hormone ethinyl estradiol was investigated on microalgae Cheatoceros muelleri. Seven different concentrations (250, 500, 1000, 1500, 1750, 2000, and 2500 μg/l) of the hormone were measured by a replicate control treatment. Factors including the size of chlorophyll a, specific growth coefficient, and protein content were measured in microalgae C. muelleri. The results showed that at concentrations of 250 and 500 μg/l, growth rate and chlorophyll a content in hormone-treated samples increased significantly compared to the control. In contrast, more protein was observed at the concentration of 250 μg/l than in the control group in microalgae. The results of this study showed that increasing the treatment period in most concentrations had a significant effect on growth inhibition and in some cases caused the growth of microalgae. Higher concentrations of the hormone also affected the growth inhibition, chlorophyll amount, and protein contents of C. muelleri.

Biological control using marine bacteria is part of the integrated management to control harmful algal blooms (HABs). The aim of the present study was to investigate the frequency and diversity of bacteria in HAB-exposed regions in Hormozgan province and to evaluate their algicidal activity against Cochlodinium polykrikoides. Seasonal frequency of bacteria in 10 stations throughout the coastal regions of Hormuz Island, Bandar Abbas, and Bandar Lengeh showed maximum frequency in St 1, St 6, and St 10 in spring. We identified 10 bacterial families in sediment samples, which dominantly belonged to Vibrionaceae, Entrobacteriaceae and Pseudomonadaceae with 29%, 14 %, and 12% frequency, respectively. While in seawater samples Entrobacteriaceae and Vibrionaceae were dominated with 23% among 6 identified families. Approximately, 13.33% of sediment-isolated bacteria and 9.09% of seawater-isolated bacteria were able to kill whole algal cells. The extracted metabolites of the active isolates exhibited significant algicidal activity with LC50 values ranging from 90.28±3.14 to 1029±45.94 µg/ml. This study presented an overview of the frequency and diversity of bacteria in the investigated areas and provided eight algicidal isolates for future studies on the biological control of HABs.

In this study, we investigated the effects of sediment grain size and seasonal change on the structure of macrobenthic communities in the south and southeastern shorelines of the Caspian Sea for one year using a hand corer. Sediment sampling was performed at four stations (Sari, Sisangan, Khajeh Nafs-Ashuradeh, and Bandar-e-Turkmen wharf) with different substrates. Results of PERMANOVA analysis showed a significant interaction effect between the season and the sampling station. The dominant species composition varied in each station at different seasons. Stenogammarus sp. and A. improvisus and P. eichwaldiana contributed to 100% dissimilarity between Bandar-e-Turkmen and Farahabad shorelines in summer, winter, and spring. In all seasons, Stenogammarus sp. was dominantly present in most sampling replications with a uniform frequency at the Sari shoreline. C. albidus and C. littoralis species were dominant in Khajeh Nafs-Ashuradeh and Sisangan stations during four seasons, respectively. Based on dbRDA plots, the sediment organic matter and electrical conductivity in summer; salinity, pH, and silt percentage in autumn; sediment organic matter and pH in winter; and organic matter and percentage of clay in spring had a substantial role in the distribution of macrobenthos and their frequency differences.

In this study, we examined the effect of herbal medicine Hemolax in neutralizing of 5 mg/lit glyphosate poison in the liver of zebrafish, Danio rerio. We also examined the combined effects of poison and Hemolax as well as the effects of each drug separately for 10 days in Zebrafish. This experiment was designed in five treatments and three replications. According to the results of liver tissue, histopathological effects in the drug–toxin treatments were less than the groups that were consumed the drugs.