نشریه علوم و فنون شیلات
سال دهم شماره 2 (پیاپی 34، بهار 1400)

Fish are among the organisms that have the ability to bioaccumulate these metals. The aim of this study was to investigate the concentrations of aluminum, vanadium, tin and chromium in the muscle tissue of tapeworm and assess its potential risk. For this purpose, 30 pieces of fish were caught in July 2017 from Bushehr port, Persian Gulf. Samples were prepared according to standard laboratory methods and the concentration of heavy metals was measured using ICP-OES. The concentration of elements in the muscle tissue of fish for human consumption was compared with international standards, as well as the estimated daily, weekly absorption in children and adults, their permissible consumption and risk indicators of consumption of this fish against carcinogenic diseases. The results showed that the mean concentrations of aluminum (23.9 ±10.3), vanadium (0.15 ±0.07), tin (5.41 ±2.2) and chromium (0.34 ±0.12), based on micrograms per gram, fresh weight was observed in muscle tissue.  The absorption of the studied metals in the muscle tissue of fish was Al> Sn> Cr> V. The results showed that the permissible consumption of heavy metals with the exception of aluminum was lower than the standard of the World Health Organization. The calculation of the risk index showed that aluminum in both groups of adults and children and chromium in children have values ​​of more than one, in this regard, with continuous monitoring of heavy metal surfaces in fish offered in the market

The socio-economic data of shrimp fleet in Bushehr province for 2019, were collected in order to determine the role of this fisheries in creating employment, income and development of coastal areas of the Persian Gulf. The data were collected using a questionnaire. The fishing fleet of shrimp in Bushehr province includes 470 vessels, that, in addition to shrimp, catch fish and other aquatic animals outside the shrimp fishing season.Based on the analyzes, the number of fixed job created by shrimp fishing fleet in Bushehr province, were 3756.2. The total number of jobs created (fixed, temporary and seasonal) was calculated to be 3934.2. Fixed job and the total number of job opportunities created (fixed, temporary and seasonal) by each vessel were 8.0 and 8.4 people, respectively. Analyzes showed that more than 98% of the annual income and livelihood of crews and their families depend on shrimp fleet. The annual working hours of each of the personnel working on the vessels were calculated to be 2110.2 hours, which in 2019 was about 2% less than the full-time equivalent working hours on a national scale (2107 hours) and 3% more than the full-time equivalent working hours on an international scale (2000 hours).

This study was conducted to determine the temporal and spatial distribution of Opusia indica in the Hara Biosphere Reserve in the Persian Gulf. Seasonal sampling (four seasons) was performed from winter 2019 to autumn 2019. Sampling was done in five regions and three habitats within each region using metal quadrats with dimensions of 25 × 25 cm. In each habitat, environmental parameters including temperature, salinity, dissolved oxygen, pH along with organic matter and grain size were measured. The results showed that the abundance and biomass of Opusia indica have decreasing trend with increasing habitat complexity. Seasonally, the highest abundance and biomass were observed in winter and autumn, respectively, and the lowest abundance and biomass were observed in spring. There was a significant difference between habitats and seasons (p <0.05). Salinity showed a significant difference between habitats but didnchr('39')t have seasonal changes. While temperature didnchr('39')t show a significant difference between habitats, but it had seasonal changes. There was a significant difference between dissolved oxygen levels and pH between habitats and seasons. Significant changes were observed between habitat and seasons in sediment grain size, while the amount of organic matter showed only differences between habitats. Also, analysis of Kendall correlation between environmental factors (temperature, salinity, dissolved oxygen and pH) with abundance and biomass showed that there was a significant correlation between these environmental factors but no significant correlation was observed between abundance and biomass with the amount of organic matter. The results help to better understand the situation of this species in the mangroves ecosystem.

The aim of this study was to investigate the rate of changes in liver enzymes in the plasma of Epinephelus stoliczkae under the exposure of different concentrations of potassium dichromate during 21days in vitro.

200 pieces of Epinephelus stoliczkae with average total length 29.6±2.2cm and average total weight389.5±92.4g were caught from the Oman Sea. Three treatments of 3.6, 7.31 and 14.6mg/L chromium(three replications and one control) were selected to sub-lethal toxicity test. The fish were exposed to chromium for 21 days and at 0.5, 1, 7, 14 and 21 days after the start of the experiment to measure the levels of liver enzymes aspartate aminotransferase(AST), alanine aminotransferase(ALT) and alkaline Phosphatase(ALP), blood was obtained from tail stems of fish. The amount of enzymes was measured using photometric method and values ​​were expressed inU/L.

The highest and lowest levels of liver enzymes in Epinephelus stoliczkae were: aspartate aminotransferase=198.16±6.21-298±10.28, alanine aminotransferase=38±2.56-81±2.19, alkanin phosphatase=118±4.21-177±2.7U/L.Over time, the amount of liver enzymes in different treatments increased compared to the control group and showed a statistically significant difference(P<0.05).For all three liver enzymes, the highest amount was recorded in the third treatment and 21 day and the lowest in the first treatment and time of 0.5 days.

In this experiment,liver enzymes increased in response to an increase of chromium concentration and duration of exposure, which could be due to damage the liver cells and release of liver enzymes into the plasma.In general, liver enzymes can be used as biomarkers of pollution in natural environments.

This study was conducted to investigate the morphological variation of Planiliza abu in the Tireh (Tigris Basin), Kor (Kor River Basin) and Jegin (Hormozgan Basin) rivers using traditional (TM) and geometric morphometric (GM) methods. For this purpose, a total of 62 specimens were collected using electrofishing device and Salik net. In the Lab, 21 morphometric traits were measured. Then, to extract the morphological data in the geometric method, 16 landmark-points were defined and digitized on the photographs taken from the left side of fish using tpsDig2 software. The results showed that the studied populations had significant differences in 7 morphometric traits (P<0.05). The differences in the geometric method were those of the head size, body depth, pectoral fin position and caudal peduncle length. Based on the results, GM method showed higher accuracy to reveal the morphological variations in the generalist species of Planiliza abu, which can inhabit a wide range of habitats.

In this study, coastal sediments of Qeshm, Bandar Khamir and Bandar Laft regions in Hormozgan province were studied to determine the level of contamination of heavy metals lead, nickel, zinc, iron and copper by natural processes or human activities. In order to identify environmental pollutants caused by heavy metals, shovel sampling was performed from the sediments of these areas to measure the concentration of heavy metals and determine the enrichment index. The location of the samples was determined using a GPS device and sampling of surface sediments (tidal zone) was performed at 30 stations in the study areas. Atomic absorption of flame spectrometry was used to determine the concentration of heavy metals. The results showed that the mean concentrations of heavy elements lead, nickel, zinc, iron and copper in all sampling stations showed a significant difference (p<0.05). In terms of concentration of studied elements in Qeshm region (copper: 33.76 ± 1.88, zinc: 85.44 ± 2.75, lead: 31.79±  1.23, nickel: 34.17 ± 2.29 and Iron: 38000±691.21 μg/g) compared to Bandar Khamir (copper: 26.84 ± 2.30, zinc: 77.54 ± 2.12, lead: 24.71±  1.37, nickel:25.82± 1.30 and iron: 36810± 482.882 μg/g) and Bandar Laft (copper: 22.74± 2.42, zinc: 65.22±2.61, lead: 19.93± 1.32, nickel: 21.70±2.06 and iron: 35560±1014.56 μg/g) had higher contamination. The results also showed that the metal enrichment factor is low in all sediment samples and in terms of Müller geochemical index, the degree of soil contamination is in the category of non-contaminated soils.

Steroids are one of the most important and abundant secondary metabolites of marine sponges. The aim of this study was to investigate the antibacterial properties of steroidal fractions derived from the Persian Gulf sponge Axinella sinoxea. Extraction was first done by Acetone and then the fractions were separated through column chromatography with silica gel. Identification of steroidal fractions were done by thin layer chromatography (TLC) and gas chromatography coupled with mass spectrometry (GC–MS). Then, antibacterial properties of steroids were identified and minimum inhibition concentration (MIC) and minimum bactericidal concentration (MBC) were investigated by tubular dilution. Two types of steroids including Stigmasta-5,24(28)-dien-3-ol,(3β-24Z) and Ergosta-5,22-dien-3-ol,(3β,22E,24S) were determined. The extracted steroids showed different results regarding the growth inhibition and bactericidal effect on Gram negative (Escherichia coli, Klebsiella pneumoniae and Vibrio harveyi) and Gram positive (Micrococcus roseus and Staphylococcus aureus) bacteria at different experimental doses. In conclusion, promising results were found regarding the antimicrobial effects of the extracted steroids of the marine sponge from Larak island A. sinoxea. These findings reveal the necessity of more comprehensive investigations for the synthesis of pharmaceutical and antibiotic materials from the  bioactive compounds.

The Persian Gulf has a different environment for corals compared to other parts of the world. 17 coral islands and some coastal areas in the northern part of the Persian Gulf as well as Chabahar Bay in the Oman Sea are the most important coral regions of Iran. The inaccessibility of coral islands and the dispersion of research have led to inaccurate information on the number of coral reef species identified. In this research, by field study of some coral regions such as Shidvar, Farsi, Kharg, Khargo, Hindurabi and Nayband, as well as collecting studies conducted by other researchers in other coral regions, thorough information about the diversity of coral species identified in the Persian Gulf have been presented. According to studies, the number of species of coral reefs identified in the Persian Gulf waters is 96 species, which by calculating 6 species of coral reefs that are reported only from Chabahar Bay, brings the number of species identified in Iranian waters to 102 species. The identified species are from 13 families and 40 genera, among which, Merulinidae and Acroporidae each with 29 and 23 species, respectively, have the highest diversity in terms of number of species. After these two families, Poritidae with 11 species has more diversity than other families. Among the studied islands, Larak Island has the highest number of species.

In this experiment, head wastes were prepared and enzymatically hydrolyzed using alcalase (2.4 L) enzyme. The hydrolysate was fractionated by ultrafiltration with 10 kDa molecular weight cut-offs and the desired fraction was encapsulated following ion coagulation method (chitosan and triphosphate (TPP)) in nanochitosan capsules. Encapsulation process was optimized based on different ratios of chitosan:TPP and different concentrations (1, 5 and 10 mg/ml) of peptidic fraction. Finally, the degree of hydrolysis and the length of the peptides obtained from enzymatic hydrolysis were determined. The nanocapsules were examined for size, zeta potential and polydispersity index (PDI) using dynamic light scattering (Malvern, England). Structural and surface morphology studies including scanning electron microscopy (SEM) and infrared spectroscopy (FTIR) of capsules produced under favorable conditions were also performed. Particle size was measured in various concentrations and treatments in the range of 30 to 150 nm. The best results were obtained in the treatment of 2: 1 ratio of chitosan to polyphosphate and concentration of 10 mg / ml. The size, dispersion index, zeta potential and size of nanocapsules in the optimal conditions were 0.375, 2020 and 30.13 nm, respectively, and storage conditions at -20 °C had no effect on the quality of nanocapsules. Based on the efficiency study, it was found that fraction with a concentration of 10 mg/ml is well encapsulated by chitosan with an efficiency of 91.04 ± 0.18 percent. The results showed that chitosan-TPP could be used for nanocapsulation of bioactive peptides with an approximate molecular weight of less than 10 kDa.

Piscidin has a wide range in killing microorganisms including bacteria, fungi, viruses, parasites and has strong anti-tumor activity and plays a role in increasing innate immunity and also does not provide resistance against bacteria; Therefore, it is of great importance in aquaculture. In this study, piscidin gene of Sparus aurata in vector pTZ57R / T was cloned. In this research, ligation product was transferred to component cell of E. coli DH5α strain. Plasmid extraction was performed from single colonies observed in ampicillin plate. Confirmation of the accuracy of single colonies grown in this research was performed by direct PCR and sequencing. The amplified cDNA fragment of the gilthead seabream piscidin gene consists of 310 nucleotides and 57 amino acids. The results of this research show that piscidin gene has been successfully cloned in pTZ57R / T vector. Comparison of nucleotide sequence of piscidin gene in this study showed high similarity with piscidin 5  of Morone chrysops. The comparison of the amino acid sequence of signal peptide piscidin is quite similar to Dicentracin-like of that species registered in the genebank, and mature peptide piscidin sequence is similar in only three amino acids to Pleorocidin-like of Poesila farmosa and Dicentracin-like of Sphaeramia orbicularis. This study could be a step towards further studies of piscidin peptide.

The aim of this study was to identify different population broodstocks of Litopenaeus vannamei and effect of inbreeding and cross-inbreeding on genetic characteristics and inbreeding coefficient of offspring in the next generation. According to origin of broodstocks kept in hatcheries of Bushehr province in the first generation, different populations were identified through microsatellite method from Hybrid, High health and Molokai stocks then, in the next generations genetic characteristics of offspring from their inbreeding and cross-inbreeding were examined. The results showed that the amount of genetic diversity in Molokai and High Health stocks (0.46±0.09 and 0.50±0.07) was more than hybrid stock (0.38±0.06). The inbreeding coefficients of Molokai, High Health and hybrid stocks were 0.14, 0.31 and 0.41, respectively. Due to the low genetic distance between the hybrid and Molokai stocks, after mixing them together Molokai and High Health populations were introduced as the first generation broodstock. In the second generation, despite the high genetic diversity in the offspring of Molokai×High Health (0.47±0.12) and High Health×Molokai (0.39±0.08) than the offspring of Molokai×Molokai (0.19±0.04) and High Health× High Health (0.11±0.03), these values were reduced compared to the first generation. The lowest and highest inbreeding coefficients were related to the offspring of Molokai×High Health (0.268 ±0.18) and Molokai× Molokai (0.853±0.145), respectively. According to the results, it can be said that the lack of knowledge about the genetic characteristics of broodstocks and mating between individual relationships (full and half sib) can reduce genetic characteristics and genetic depression due to increased inbreeding coefficients in next generations.

In this study, the morphometric and meristic characteristics of Psettodes erumei in two regions of Bandar Abbas and Bandar Jask were investigated. Up to30 Psettodes erumei fish were prepared from each region and after performing bioassay operations, 29 morphometric characteristics and 9 meristic characteristics were measured and counted. According to the results, the average coefficients of variation in the morphometric characteristics of right-handed and left-handed fish in Bandar Abbas region are 0.34 and 0.41, respectively, and the average coefficient of variation of meristic factors of right-handed and left-handed fish is 0.14 and 0.17. The mean coefficients of variation of morphometric factors of right-handed and left-handed fish of Bandar Jask are 0.25 and 0.24, respectively, and the mean coefficient of variation of meristic factors of right-handed and left-handed fish is 0.10 and 0.10. Also, Psettodes erumei fish had a significant difference in 25 morphometric factors and 1 meristic factor between these regions (P <0.05). The height of the anterior fin, the height of the dorsal fin, the height of the ventral fin on the dark and light surface, the length of the base of the thoracic fin on the dark and light surface and the width of the mouth are the most important morphometric factors. There was no significant difference between the parameters measured in Psettodes erumei fish in any similar area (P> 0.05). According to these results, the differences between the morphometric and meristic characteristics are more pronounced, which is itself due to different environmental conditions in these two regions.

Oil pollution of waters, in addition to disrupting the physiological function of fish, leads to irreparable damage to human health during transmission through the food chain. Therefore, the possibility of accumulation of petroleum hydrocarbons in the edible tissues of fish is of particular importance. In this study, samples of yellowfin seabream (Acanthopagrus latus; Houttuyn, 1782) were collected from the Khowr-e Musa area in the Persian Gulf using bait traps. after twenty days of adaptation to the laboratory conditions (South of Iran Aquaculture Research Center), the fishes was divided into five groups with two replications in tanks containing 300 liters of seawater. The groups were then exposed to concentrations of 0, 2, 4, 8 and 16% water associated fraction (WSF).The results of the study of the amount of total petroleum hydrocarbons in the gills and kidney tissue showed a significant increase on days 10 and 20 of the experiment, which increased slightly with increasing WSF concentration (P <0.05). While liver and muscle tissue, considering exposure time and WSF concentration, no significant difference was observed (P> 0.05). The results of the present study showed the possibility of accumulation of TPH in the gill and kidneys of yellowfin seabream, under the influence of concentration and duration of exposure to WSF. Therefore, considering the high economic value of the Sparidae family, it seems necessary to provide appropriate management methods to control oil pollution in the Persian Gulf.

Squalene is an unsaturated triterpene hydrocarbon and is a precursor of steroids and cholesterol with antioxidant properties. The aim of this study was to isolate the squalene from the liver of the Persian Gulf spot tail shark Carcharhinus sorrah and to investigate its antimicrobial activity. Extraction was first done by methanol 70% and then, the squalene was separated through column chromatography with silica gel. Identification of the extracted squalene was done by thin layer chromatography (TLC) and gas chromatography coupled with mass spectrometry (GC–MS). Antibacterial properties of the squalene were identified and minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were investigated by tubular dilution. Identification of the extracted compounds by GC-MS confirmed the presence of the squalene in the shark liver. Antibacterial studies showed that the squalene inhibited the growth of Gram negative (Escherichia coli, Klebsiella pneumonia and Vibrio harveyi) and Gram positive (Micrococcus roseus and Staphylococcus aureus) bacteria. Therefore, this metabolite has the potential to be more investigated for developing new antimicrobial compounds.

The aim of this study was to investigate the antioxidant effect of cucumber hydrolyzed protein (Holothuria leucospilota) and its effect on microbial and chemical properties of silver carp (Hypophthalmichthys molitrix) at refrigerator temperature. Enzymatic digestion of cucumber muscle was performed using alkalase enzyme (1.5% of weight of raw material, 55 °C and 4hr). Surimi was prepared from silver carp fillet and added to it at two concentrations of 0.5 and 0.1 mg/ kg of hydrolyzed protein. Antioxidant activity, peroxide value (PV), total volatile nitrogen bases (TVB-N), thiobarbituric acid (TBA), pH, volatile fatty acids (FFA), aerobic mesophilic bacterial count and psychrotroph bacteria on 0, 3, 6, 9, 12 and 15 days were performed. The rate of free radical scavenging by cucumber hydrolyzed protein at 0.5 and 0.1 mg/ kg was 92.24% and 62.11%, respectively, which showed a higher value than the commercial antioxidant BHT (p< 0.05). The amount of peroxide in the treatment was 0.1 mg/ kg until the ninth day and in the treatment of 0.5 mg/ kg until the twelfth day was within the allowable range. The results of TVB-N, TBA, FFA, aerobic mesophilic bacterial and psychrophilic bacteria in both treatments and on the days of the study did not exceed the allowable limit. This study showed that cucumber hydrolyzed protein is able to control bacterial load and oxidation process in silver carp surimi. Treatments containing cucumber hydrolyzed protein could increase the shelf life of surimi for 9 days compared to the control treatment.