فصلنامه شیلات
سال هفتاد و ششم شماره 3 (پاییز 1402)

Mitochondrial genome is an ideal model to study evolution and phylogenetic relationships. In this study, complete mitochondrial genomes of six species of Caspian sea sturgeon including Persian sturgeon, Russian sturgeon, Ship sturgeon, Sterlet sturgeon, Starry sturgeon and Beluga sturgeon along with separate nucleotide and amino acid sequences of 13 PCGs per each genome including ND1, ND2, ND3, ND4, ND5, ND6, ATP6, ATP8, COX1, COX2, COX3, ND4L and CYTB were retrieved from NCBI database and compared. The results obtained from sequence distance analysis by DNAStar software based on complete mitochondrion genome showed high genetic similarity (99 %) between Persian and Russian sturgeon. Also, the lowest similarity (95 %) was observed between Sterlet and Starry sturgeon. In phylogenetic analysis by MEGA7 software, two main clusters with two sub-clusters for one of the main clusters were identified. Persian and Russian sturgeon species were grouped in first sub-cluster, Ship and Sterlet species fall in the other sub-cluster and Starry sturgeon with Beluga formed a different distinct cluster. The results obtained from the comparison of the 13 PCGs sequences were similar to the sequences of the complete mitochondrial genomes. The most difference in nucleotide sequences were observed in CYTB, ATP6, ND2, ND5 and ND6 genes and the lowest difference for ND4L gene. The results obtained from the comparison of the 13 genes amino acid sequences were different as the order of the species was changed and 100 % genetic similarity were observed for some genes such as COX3 and ND4L genes. Based on the results of the present study, mitochondrial genome sequences could be used for phylogenetic analysis and clustering of different species of sturgeons. However, the accuracy of investigations by complete mitochondrial genomes is higher than the nucleotide sequences of the genes, and using the amino acid sequences is not suggested due to their codon nature.

Phosphorus plays an important role in the growth of algae, production of fatty acids and metabolic processes such as energy transfer and photosynthesis. This study aimed to determine the effect of different phosphorus (P) concentrations on the growth, biomass, phenolic content and antioxidant properties of Microcystis aeroginosa and Anabeana variabilis. After identifying and isolation the desired cyanobacteria, in a completely randomized experimental design was conducted with four different concentrations of Phosphorus in the media, including zero, 0.5, 64 and 256 µgP/L, each in triplicates, using BG11 medium for a 10- day period culture. The average cell density in the treatments of 0 (control), 0.5, 64 and 256 µg/L of P for M. aeroginosa were recorded at 5.2×105, 6.4×105, 10.6×105 and 11.3×105 cells/mL, respectively, for A. variabilis were 2.8×105, 3.4×105, 7.7×105 and 1.4×105 cells/mL, respectively. The amount of total phenolic for M. aeroginosa were 0.5, 1.5, 5.12 and 7.75 mg gallic acid/ DW and for A. variabilis were 4.12, 4.9, 9 and 66.0 mg gallic acid/DW. The DPPH free radical inhibition percentage for M. aeroginosa were equal to 20.51, 22, 23 and 39.23% and for A. variabilis, 25.9, 32.56, 45.12 and 34.1% were calculated. The results showed that the highest growth, photosynthetic pigments and total phenolic as well as antioxidant content were obtained for M. aeroginosa at a concentration of 256 µg/L of P and for A. variabilis at concentration of 64 µg/L of P. Therefore, it can be concluded that the requirement of P in algae is different according to the species, so that each species shows the highest growth rate and other biological activities at a certain concentration of P. Also, understanding the growth of cyanobacteria in relation to the concentration of nutrients in which lead to their bloom is importance for their management of natural water resources, especially fresh and drink waters.

Due to rapid aquaculture development, limited supply of fishmeal and its increasing cost and demand, using plant derived feed ingredients such as legumes (lupin and peas), oil seed cakes (soy bean, cottonseed, and rape seed), cereals (corn, rice and wheat), meals of protein rich leaves, concentrates and isolate of non-edible oil seeds (jatropha, castor and neem) as fish feed ingredients is compulsory. However, the major challenge in utilizing the protein rich plant ingredients is the presence of anti-nutritional factors. Anti-nutritional factors are compounds which reduce the nutrient utilization and/or feed intake of aquatic animals and are important in plant origin feed ingredient contents of feed formulation. These factors can cause malnutrition or reduced micronutrients and minerals uptake. The most important anti-nutritional factors include protease inhibitors, phytic acid, saponin, tannin, cyanide, oxalate, gossypol, non-starch polysaccharides, phytoestrogens, mimosine and mycotoxins. There are various traditional and recent technologies, which can be used to reduce the levels of such anti-nutrient factors. Several processing techniques including fermentation, germination, dehulling, autoclaving, soaking etc. are applicable to reduce the anti-nutrient contents of ingredients. However, investigating and appreciation of effective methods and optimizing the conditions of their application is still very demanding. In addition, each aquatic species has tolerable threshold for each of the anti-nutritional substances, which should be considered before choosing the processing method. Other issues including the environmental concerns of the processing method and its economic viability also deserve special attention.

In recent years, many bioactive compounds has been extracted, described and purified from cephalopods. These invertebrates are a very rich source of sulfated polysaccharides with new structures.  The aim of this study was investigation of anticoagulant Glycosaminoglycans extracted from Sepia Pharaonis tentacles. Following the separation of their tentacles terminal portion, 21g of the wet weight was freeze-dried. First, glycosaminoglycans were extracted using 5g wet weight and 4g dry weight, separately, by Cetyl Piridinium Chloride cationic salt. In order to do identification of extracted glycosaminoglycans and compare with heparin, the FTIR spectrum was used. Activated Partial Thromboplastin Time (APTT) and the Prothrombin Time (PT) methods were used for anticoagulation properties. Results showed that 5g (wet weight) and 4 g (dry weight) of tentacles contain 250 and 800 mg of the Glycosaminoglycan, respectively. Also, the FTIR spectrum results confirmed the presence of heparin-like compositions among extracted glycosaminoglycans. Investigating the anticoagulation properties indicated that the extracted compositions have this property and increasing concentration enhance the clotting time of the human blood, significantly. According to the present study results, squid tentacles contain glycosaminoglycans which could act like heparin but significantly weaker antithrombotic feature than heparin.

Bacteria release membrane vesicles into the extracellular environment but their activity is unknown. In this study, the use of extracellular vesicles isolated from the probiotic Bacillus licheniformis to protect rainbow trout fillets against spoilage and reduce of fillet quality was investigated. The probiotic B. licheniformis was isolated from edible fish. Probiotic vesicles were also made using the ultracentrifuge protocol. There was a significant difference in the size of probiotic-derived vesicles after 8, 24 and 48 hours of incubation. The results showed that after incubation until 16 hours, the number of cells increased to 8.09 10 108 CFU / ml. The pH reduced and reached to 4.002 at 24:00, which was the best incubation time for the bacterial growth. The vesicles derived from the probiotic B. licheniformis were collected and exposed to Shewanella putrefaciens at a concentration of 1011-107 vesicles per ml to confirm the antibacterial activity at 1011-10 vesicles per ml. Ml, with 44.34% had the highest inhibitory power of bacterial growth. Finally, rainbow trout stored at 4 ° C after covering with vesicles derived from probiotics and 0.5% sodium erythorbate were stored for 5 days, followed by red markers and Fillet quality indicators were examined. The results showed that the freshness and quality indicators of fish including peroxide, TVBN, total count of fillet bacteria and thiobarbituric acid in the group receiving probiotic-derived vesicles were lower than control group and the low-dose vesicle-derived group. Of probiotics. According to the results of this study, membrane vesicles isolated from the probiotic B. licheniformis have the potential for use in the food and storage industries while maintaining the appearance of fillets, and this new substance is a beneficial antibacterial agent for a long time and increase the longevity of fish fillets.

The discharge of nanoparticles, including silver nanoparticles used in various industries into the environment, and their potential toxic effects on plants, animals and humans has raised global concerns, highlighting the need for more research on this topic. The aim of this study was to investigate the toxicity of silver nitrate salt (AgNO3), γ-irradiated (10 kGy) (AgNPs-γ) and non-irradiated (AgNPs) silver particles synthesized by the alcoholic extract of bee propolis at different concentrations (10, 50, 100, 200 μg/l) on Chlorella vulgaris microalgae. The results demonstrated that exposure to AgNPs-γ and AgNPs and silver nitrate salts increased growth inhibition (%) in a dose-dependent manner (P<0.05). Moreover, cell viability (VC %), microalgal cell density/biomass (μ/L) and chlorophyll-a concentration decreased. In contrast, electrolyte conductivity/living cells (electrolyte leakage (EL %) increased in the exposed groups, compared with the control group (P<0.05). These results showed the following trend in inducing toxicity, inhibiting growth and photosynthesis in Chlorella vulgaris: AgNO3 < AgNPs < AgNPs-γ.

In this study, in order to evaluate the possibility of cryopreservation of C. calcitrans, 4 cryoprotectant agents (dimethyl sulfoxide, methanol, glycerol and ethylene glycol), each with different concentrations (2.5, 5, 10, 15, 20, 25% (v/v)), were taken as experimental treatments. Then, microalgae samples were placed at -196°C for 30 days. After that, in order to determine the best treatments, re-cultivation of microalgae was carried out and growth performance, biochemical composition and fatty acid profile were measured. After thawing, regrowth of microalgae cells was observed in 15 out of 24 treatments. The highest final cell density (4.13x106 cells/ml) was observed in DMSO15. After thawing, in the treatments in which the cells were reproduced again, the viability ranged between 8.26 and 28.19 percent. Maximum viability index were recorded in DMSO15, DMSO10 and ME15, respectively. Biochemical composition analysis showed that there was a significant increase on the lipid content in the experimental treatments compared to the control group (p<0.05). No significant difference was observed on the fatty acid profile(p>0.05). The results showed that the cryopreservation of C. calcitrans can be successful only if we use DMSO (5-15%) or ME (10-15%) as a cryoprotectant, and the best results are obtained when using DMSO at the level of 15%.

The present study was conducted in order to monitor the water of the reservoir behind the Boostan Dam using the phytoplankton population and Palmer index for one and half years. The sampling was done seasonally in five stations from depths of 0.5 to 3 meters using One-liter Ruttner sampler. After identifying phytoplankton species; the Shannon-Wiener diversity index, Margalf richness index, Simpson index, Pillo's species uniformity index, and also Palmer's pollution index were determined. According to abundance, 5 phyllums were the dominant phytoplankton groups; Bacillariophyta (56%), Chlorophyta (23%), Cyanophyta (13%), Euglenophyta (4%), and Pyrophyta (4%). In this area, the Shannon-Wiener diversity index showed an average level of biodiversity. The highest value of the Pielou (0.88) and Simpson (0.95) indices were obtained in the summer. The lowest value of the Margalef index was calculated in the summer with a numerical value of 2.82. The results of Palmer's index showed that the water of reservoir behind the Bostan Dam is categorized at the level of very high organic matter pollution.

In terms of catch, Jinga shrimp (Metapenaeus affinis) occupies the first place in the waters of Khuzestan province, and the livelihood and economy of the local fishing community of this province depend on that. To this end, this study used LBB model as a new and powerful method based on length data to obtain length indicators for management of Jinga shrimp fishery in coastal waters of Khuzestan province in 2021. The estimated B/BMSY value of Jinga shrimp stock of 1.3 indicates that the stock of these shrimp is in a relatively healthy condition but is on the verge of overfishing. The values of F/M (reference value below 1) and B/B0 (reference value 0.4-0.5) also confirm this. The B/B0 value was estimated to be 0.47, which means that the exploitation rate of the stock is 53%. The ratios M/K, F/K and Z/K were also estimated to be 0.65, 1.7, 1.11 and 2.81, respectively. The results related to the length in the first catch (Lc), the optimal length in the first catch (Lc-opt) and the optimal length of the catch (Lopt) showed that their values were 13.24, 0.24 and 0.30 mm, respectively. In this study, the ratio of Lc/Lc-opt was greater than 1, and the indices Lmax5%/Linf and L95%/Linf were calculated with values greater than or equal to 0.8, respectively. However, the ratios of Lmean/Lopt and Lmean/ LF=M were almost less than 1, showing that the harvest is not optimal. According to the results of this study, although the stock of Jinga shrimp is healthy, in order to ensure the maximum biomass of the cohort and prevent overfishing of Jinga shrimp in the long term, a proper management approach should be adopted based on the important length indicators.

In the present study, changes in the quality indices and shelf life of fresh fillets of narrow-barred Spanish mackerel (Scomberomorus commerson) and Javelin grunter (Pomadasys kaakan) were investigated over a 12-day storage period in the refrigerator using sensory, chemical (pH, TVB-N, PV, TBARS), and microbiological (mesophilic and psychrotrophic bacterial counts) indices. The sensory scores of both fish fillets reached less than 4 (the acceptable limit for consumer acceptance) on the sixth and eighth days of storage, respectively. The mesophilic and psychrotrophic bacterial counts in the fillets of both fish increased with an increase in storage days, although the rate of increase was different between the two groups, and psychrotrophic bacteria increased to a greater extent with an increase in storage days. The pH of the fresh mackerel and grunter fillets decreased from 6.52 and 6.24, respectively, at the beginning of the storage period to 7.49 and 7.25, respectively, on the final day of storage. The TVB-N level in both fish increased with an increase in storage days and reached 28.36 mg N/100g in mackerel and 36.25 mg N/100g in grunter on the twelfth day of storage. The lipid oxidation indices, namely PV and TBARS, in the fillets of both fish were significantly higher at the end of the storage period than at the beginning. The results of sensory, microbiological, and chemical indices showed that the maximum shelf life of narrow-barred Spanish mackerel and Javelin grunter fillets is 6 and 8 days, respectively.

In order to investigate the changes in the population indices of Otolithes ruber fish during the years 1992 and 2022, the biometry of 3551 tigertooth croaker fish was done and the average length 42±8 cm and 38±7 cm, respectively. The average weight of this species was 642±130 grs in 1992 and 638±180 grs in 2022. The relationship between fork length and body weight for the year 1992, was W=0.012*L2.95 (R2=0.85, N=750) and for the year 2022, was W=0.05*L2.56 (R2=0.86, N=703). Von bertalanffy equation for this species in the northern waters of the Oman Sea (Sistan and Baluchistan Province) was calculated in 1992 and 2022, respectively as Lt =66 (1-exp (-0.41 (t +0.32)) and Lt =66 (1-exp (-0.59 (t +0.32)). The maximum sustainable yield (MSY) and the ratio of current biomass to initial biomass (B/BV or B/B0) in 1992 and 2022 was estimated as 1293 tons, 0.40 and 2417 tons, 0.35, respectively. The ratio of spawning potential based on length in 2022 and 1992 were 0.4 (0.36-0.44) and 0.5 (0.4-0.59), respectively. Based on data of decrease in the average length, increase of fishing, total mortality and ratio of the fishing mortality to the fishing mortality of the maximum sustainable yield (F/FMSY >1), it can be concluded that there are reasons for overfishing.

In the research, the demographics of recreational fishermen of some fishing clubs in Tehran province were investigated. The research was done in a period of one year, with monthly face-to-face interviews with the recreational fishermen present in the clubs from March 2022 to March 2023 by a researcher-made questionnaire. Demographic factors including: gender, age, marital status, education, occupation and monthly income were investigated through questionnaires. The data obtained from the questionnaire was analyzed using SPSS software. The results showed that men participate in recreational fishing much more than women. In addition, the age distribution was different, adults (31 to 40 years old) participated the most. While people under 10 years of age did not participate in this field. Among them, people with higher education (bachelor's degree) had the highest participation compared to people with low education. This study provides more insight into the fishing culture in Iran. In addition, this partnership model can be used for future recreational fishing partnerships.