نشریه علوم آبزی پروری ایران
سال دهم شماره 2 (پاییز و زمستان 1401)

This study was conducted in sturgeon farms along the Caspian Sea coast in Gilan province. The aim was to evaluate the quality of incoming water and effluent of 6 farms. Sampling was performed from April to December 2017. Turbidity parameter by turbidimeter, total soluble solids by TDS meter, orthophosphate and total phosphate by Ascorbic acid method of antimonyl tartrate, ammonium by initial generation distillation, nitrate by cadmium reduction method, dissolved oxygen with Winkler method, coliform bacteria were measured by MPN, oil and fat by gravimetric method and other parameters were measured by standard methods. There was a significant difference in the mean of the parameters in all centers. The average field phosphate was measured 0.17±0.05 mg / l, which was much higher than the WHO standard. Also, the average field effluent turbidity (29.69±1.60 Ntu) was slightly higher than the EPA standards WHO showed. Also, according to the obtained results, the average of total water-soluble solids showed values much higher than the standard of the World Health Organization with an average of 4466.07± 87.70 (mg/l). Another parameter considered in the present study was the average number of coliform bacteria in the effluent, which showed high values compared to the standard. Based on these results, treatment of effluent before its release into aquatic environments is recommended, which in addition to reducing the transmission of microbial contamination, minimizes the risk of atrophy and reduces the effects on the health of aquatic organisms.

Despite demanding for aquaculture products have been continuing to grow, developing this diverse enterprise is limited by lack of adequate water resources and lands. To overcome these issues, intensive aquaculture facilities could be used with water recirculating or reuse systems. One of these innovative facilities is in-pond raceway system (IPR). IPRs are effective intensive aquaculture facilities for regions with high water consumption and limited land resources and they are categorized as hybrid or integrated systems. In fact, this system overcomes the problems and bottlenecks of each system by combining various features and advantages of other aquaculture systems. These developing facilities are consisting of several rectangular raceways installed in a pond. IPRs design is more efficient than the ponds and cages due to greater accessibility for feeding, grading, harvesting, and disease treatments and by comparing with other systems, it has significantly more profit and production yield. This study reviews the main components, stocking, feeding, and aquaculture management of fish in IPRs.

This study aimed to investigate the taxonomic status of Salmo trutta inhabiting the Mardoogh, Liqvanchai (Urmia Lake basin), Haraz (the Caspian Sea basin) and Jajrud and Karaj (Namak Lake basin) rivers, and Salmo caspius (from the Caspian Sea) using the geometric morphometric method. Samplings were done using an electrofishing device in the rivers and beach seine/gillnet in the sea. To prepare geometric data, the photographs were taken from the left side of the specimens, then 16 landmark points were defined and digitized on the two-dimensional (2D) images. The data were analyzed using Discriminant Function Analysis (DFA), Principal Component Analysis (PCA), Canonical Variate Analysis (MANOVA/CVA), and cluster analysis. The intra-species morphological variations between the two studied species from the Caspian Sea basin showed significant differences in the morphometric traits, including snout position, body depth, and caudal peduncle length and depth. Based on the DFA and PCA, they were separated from each other. The results related to the interspecies examination categorized the S. trutta populations of the three studied basins in three clusters, separated from the S. caspius cluster. The resulting differences showed the morphological flexibility of these populations to their environmental conditions. The geometric morphometric method identified the studied groups at the intra and inter-species levels in terms of morphology, which helps to evaluate the stock assessment of these species and consider them as separate species in the future.

In this study, short-term storage of rainbow trout (Oncorhynchus mykiss) eggs in different environments and time periods was investigated. For this purpose, fish eggs were stored for one, four and seven days at refrigerator temperature (4°C) and in the natural ovarian fluid, Cortland buffered with Hepes and Tris-HCl, at pH=8.4. The individual egg wet and dry weights, egg diameter, storage fluid pH, fertilization, eyed and hatching percentage were measured. The results showed that egg storage time did not change wet and dry weights significantly, while egg diameter were increased significantly (P<0.05). The pH level decreased significantly with increasing storage time in all environments (P<0.05) although the highest decrease were observed in ovarian fluid,  Survival rates including fertilization, eyed and  hatching rates  were measured and indicated that the highest survival rates were obtained for eggs stored in Hepes environment. So, the artificial medium buffered with Hepes could be recommended for short-term storage of rainbow trout eggs.

Magnetic fields interact with biological systems and affect the metabolism of microorganisms such as microalgae. In fact, it can change the rate of photosynthesis and the composition of macromolecules inside the algal cell. These fields can affect the growth of microorganisms in three ways: inhibiting, stimulating, and null. For this purpose, in this study, the growth of the microalgae, Nannochloropsis oculata and Spirulina platensis, under a static magnetic field of 2.5 mT in a bubble column photobioreactors have been investigated. All conditions, including culture medium, light intensity, temperature, pH and inoculation rate for a period of 14 days were considered the same for all photobioreactors. The results showed that the static magnetic field with the intensity of 2.5 mT is a growth stimulant and has increased the biomass productivity of the studied microalgae by 34% and 10%, respectively. Also, Gompertz growth model has shown more compliance with experimental data in the conditions where microalgae have been affected by the field.

Gammarus is the largest genus of aquatic crustaceans in the family Gammaridea, with more than 200 species worldwide. These crustaceans are very important components of the food chain in running waters. Therefore, their population changes can affect all communities, especially the health of fish stocks, and disturb the balance of the ecosystem. Due to their small size, high abundance and sensitivity to environmental conditions, they are suitable as indicator species for evaluation. This study investigated the genetic diversity of the genus Gammarus between different populations in Golestan National Park. After sampling, the common identification keys were used to identify the basic morphology and the COI mitochondrial gene sequence was used to conduct molecular studies. Genealogical relationships were determined by maximum likelihood (ML) method. The genetic distance in the populations and some indices of genetic diversity (number of haplotypes (h), haplotype diversity (Hd) and nucleotide diversity (Pi)) were calculated. Based on the results of the genealogical trees, the samples were placed in two separate clades (western and central) and separated from the gene bank samples with high bootstrap. The results of molecular variance analysis showed that the diversity between populations (72.49) is more than the diversity within populations (27.51) and the value of Fst index (0.68) shows the significant genetic difference between populations and the limitation of gene flow. Haplotype diversity is equal to 0.94, the highest and lowest of which is related to Khandushan River (1.00) and Golestan Spring (.40). Also, among the identified haplotypes, 17 haplotypes had only one individual, which indicates the high diversity of Gammarus populations in Golestan National Park. Also, G. komareki was identified as a dominant species complex with many hidden species in the region that have not yet been accurately identified.

This experiment aims to evaluate the effect of colored microplastics (MPs) on oxidative stress indicators in Gambusia holbrooki. This study hypothesized that the risk of oxidative stress in fish may be different based on MPs’ color. In this study, fish in 7 experimental treatments with two replications, including the control group and six experimental groups, were exposed to 150 micrograms per liter of colored MPs (white, green, yellow, red, blue, and black colors) for 14 days. In the end, some oxidative stress indicators were assayed. Furthermore, the bioaccumulation potential of MPs was measured with an FTIR instrument. The results showed that the activity of superoxide dismutase in the liver of fish exposed to black, yellow, and red MPs is significantly higher than in the control group (P<0.05). In addition, exposure of fish to black, green, and red MPs led to a significant increase in the activity of catalase, glutathione-peroxidase, and glutathione-reductase in liver cells (P<0.05). These results showed that the risk of oxidative stress in fish exposed to black, green, and red MPs was significantly higher than other colored MPs.

River water is used for various purposes more than water from any other source. This study was designed and implemented to evaluate the water quality of the Tajan River by the Iran Surface Water Quality Index (IRWQIsc). Considering the establishment of polluting sources on the banks of the Tajan River (various agricultural, industrial, urban and domestic wastewaters), sampling was done at 9 stations with 3 repetitions in two seasons (January 2021 and June 2021), and 11 water quality parameters including; BOD5, COD, ammonium, nitrate, phosphate, turbidity, pH, fecal coliform, electrical conductivity, dissolved oxygen and total hardness were measured using standard methods in the laboratory. In the present study, the average amount of BOD5, COD, ammonium, nitrate, phosphate, turbidity, pH, fecal coliform, and electrical conductivity increased in both seasons from upstream to downstream stations, dissolved oxygen in both seasons from above It decreased downstream and the total hardness did not have a regular trend from upstream to downstream. The results of the study of the IRWQIsc index showed that this index was between 23.7 and 70.08 in the cold season and between 64.21 and 16.35 in the hot season for all the stations of the Tajan River. In general, the water of the Tajan River was placed in the descriptive-qualitative class of medium and bad, and the closer the agricultural lands were to the studied stations, the more the water pollution was. The most important source of pollution in the study area; Indiscriminate harvesting of sand and paper mills in Mazandaran, fish breeding farms, animal husbandry, sewage of Sari city, surrounding villages, effluents of paddy fields, and agricultural fields. In this regard, attention to the comprehensive management of water resources and assessment of environmental effects should be prioritized.

This study aimed to determine fecundity in relation to age and size, and the correlation between fecundity and egg diameter with whole body weight, total length and age in migratory kutum, Rutilus frisii, to Sefid River, southern Caspian Sea. Ripe females were caught about 1000 m far from the river mouth using beach seine with 20 mm mesh size during their migration season in March 2021, and they were transferred into ponds of Shahid Ansar propagation and restoration center for bony fishes of Caspian Sea, Rasht city. The propagation of females was done using hormonthrapy (Ovaprim). The total length, body weight, and age of specimens were measured before artificial propagation and the weight of the gonad was measured. One gram of egg was sampled randomly and fixed into a glass containing formaldehyde 5%. Then the precise weight of the egg samples was determined using a digital scale. The examination of 98 female specimens with a weight 540-2710g (1231±384, Mean±SD) showed that working fecundity of 23577-92029 (49643±16185) eggs per individual, relative fecundity of 25.4-58.1 (40.7±6.8) eggs per gr / body weight and eggs diameter of 1.67-1.99 (1.84±0.06) mm. The working fecundity was raised with increasing fish age and size but relative fecundity decreased by increasing age and size.

The present study was performed to determine the nutritional value and fatty acids profile and amino acids in canned Skipjack tuna and yellowfin fish and compare them with their fresh meats. The amounts of protein, fat, moisture and ash in fresh Yellowfin were 6.71, 5.88, 84.66 and 0.85%, and in canned fish 39.6, 5.65, 86.56 and 0.82%, respectively, whereas, in fresh Hoover, they were 7.44, 5.24, 83.44 and in canned fish 7.65, 5.96, 83.79 and 0.8%, respectively. There were no significant differences in nutritional value (P>0.05) between those fresh and canned ones. In fresh and canned treatments, glutamic acid, lysine, leucine, arginine and alanine were identified as the most amino acids. The number of amino acids in canned Yellowfin and Skipjack tuna did not decrease significantly compared to fresh meat (P>0.05). In canned and fresh products, palmitic acid (20.65-22.03 mg/g) was the highest than other fatty acids (P<0.05). The lowest fatty acids belonged to eicosenoic acid (1.49-1.34 mg/g). In all treatments, the omega-3 fatty acid was higher than the omega-6 fatty acid (P<0.05). No significant difference was observed in the nutritional value between Yellowfin and Skipjack tuna (P>0.05). Although differences were found between the canned and fresh tuna meat, the present study showed the high nutritional value of canned Yellowfin and Skipjack. Since canned meat has higher safety and shelf life compared to fresh meat; products processed with vegetable oil may be a better choice than fresh meat for people who need an increase in essential fatty acids than fresh meat.

Regeneration is an endogenous process that culminates in restoring tissue and organ function completely. While the regeneration capacity in mammals is limited to specific tissues, lower vertebrates such as zebrafish can regenerate entire organs and most adult tissues. MicroRNAs are small non-coding molecules that regulate various biological processes (such as repair, differentiation, apoptosis, etc.) by controlling the expression of target genes. An important challenge in the study of microRNAs is to identify and predict the genes that are targeted by these small molecules. In recent years, various methods such as microarray, northern blot, and qRT-PCR have been introduced to identify the target genes of microRNAs, but the high cost has limited the use of these methods. With the advancement of computational methods and bioinformatics algorithms, target genes of microRNAs can be identified and predicted at a lower cost. In this study, an attempt was made to identify the genes and microRNAs involved in the repair and regeneration processes of zebrafish (Danio rerio) tissues using the software of Target Scan and DIANA databases with a bioinformatics approach. This research showed that the expression of Stat3, Dot1l, Pax6b, Smarca5, Mmp9, Cx43, Tnfb, Sox2, Ascl1a, and Hspd1 genes is most likely to be regulated in the process of repair and regeneration of zebrafish tissues under the influence of different microRNAs. Therefore, the mentioned genes can be suitable candidates for the laboratory investigation of genes involved in the tissue repair and regeneration process of the desired species.