نشریه بهره برداری و پرورش آبزیان
سال دوازدهم شماره 4 (زمستان 1402)

Monitoring wetlands and especially their coastlines due to recording their periodic changes gives us a better understanding of the management of these areas. Remote sensing data and satellite images are one of the reliable sources for studying and interpreting changes in wetlands. In this study, Landsat images (TM-OLI) 2007 and 2018 were examined in order to examine the changes. After performing the required processing and corrections, the NDWI index was used to separate the water and land border. Accordingly, the maximum coastline changes were in the east, west and center of the wetland with distances of 10885.82, 5781.22 and 3370.830 meters, respectively, compared to 2007. The results of the study of the wetland water area showed that the area of the wetland had a decreasing trend 2007 to 2018 (100.06 and 29.5 km2, respectively) and the most changes were related to the eastern and central parts. Overall the results showed fluctuations of coastlines and water area in the studied years have been affected by changes in the water level of the Caspian Sea. Also, this study showed the efficiency remote sensing performance and NDWI index in identifying critical area in Anzali Wetland and better knowledge of the dynamic conditions of the wetland.

This study was conducted with the aim of investigating the effect of different levels of thyroxine hormone in rearing water and diet on growth factors in the early stages of growth of rainbow trout. The experiment was carried out in three stages: hatched eggs until complete hatching, hatched larvae until active feeding, and active feeding until weighing about 1 gram of fry fish. In each stage, the experiment was performed in three concentrations of thyroxine solution (0.03, 0.06 and 0.09 mg/liter) along with the control group (without thyroxine hormone) with 3 repetitions. Thyroxine was added to water in the first and second stages and to food in the third stage. At the end of the third stage, growth indicators were examined. The results showed that the highest final weight and length in treatment 9 were 1.53±0.04 and 5.85±0.31 cm respectively. The percentage of body weight gain and specific growth factors showed a significant difference compared to other treatments (p<0.05) and were 872.45±18.32 and 5.05±0.04, respectively. The highest food conversion rate and obesity rate in the control group were 0.78±0.004 and 1.14±0.07 respectively. According to the present study, thyroxine hormone has led to positive effects on growth factors in rainbow trout fry.

Samples caught by beach seine nets in the fishing season of 2019-2021 in the southern costal zones of the Caspian Sea were used to study reproductive biology of Cyprinus carpio. Totally, 435 sea carp, including 237 female and 198 male were sampled, and their age and maturity stages were determined over sampling period. The results indicated that age range of the sampled C. carpio varied from 1 to 6 years in males, from 1 to 9 years in females, and from 1 to 9 years in combined sexes. The highest frequency of samples was in the age group of 1 for males (54.4%), 2 for females (34%), and 4 years for combined sexes (26.6%). Frequency of fish observed in the V and VI maturity stages was 45.14% and 27.17%, respectively. According to the frequency of different maturity stages and also the trend of changes in Gonado-somatic index (GSI), two spawning peaks were observed in C. carpio, including weak peak occurred in December-January and strong peak observed in March-April. The female mean length at sexual maturity (Lm50%) was 27.7 cm. Absolute and relative fecundity (mean ± SD) of C. carpio were 429310±233479 and 668±319 eggs, respectively. Since, there was an overlap between the spawning peak of C. carpio and beach seine fishing period for bony fish, it is proposed that fishing season to be banned at the beginning of April.

In this research, the comparison of the effect of adding nanoparticles (clay, chitosan, TiO2 and bacterial nanocellulose) separately on the physical, mechanical and optical properties of the film prepared from the lantern fish protein was investigated. To prepare nanocomposite films, nanoparticles were added separately at 1 and 3% levels to the protein film solution extracted from the lantern fish. The results showed that with the addition of nanoparticles in the polymer substrate, the tensile strength of all films showed a significant increase. Elongation at breaking point in films containing nanoparticles of clay, TiO2 and bacterial cellulose increased significantly and the water vapor permeability improved in films containing nanoparticles (clay, cellulose and TiO2). Also, the moisture content of the films increased with the addition of nanoparticles and the solubility values showed a significant increase in the rest of the films containing nanoparticles, except for cellulose nanoparticles. The opacity of the films also increased with the addition of nanoparticles.

In this study, sampling of commercial vessels of Afsoon 1 was carried out in July 2020, at a distance of more than 10 miles in longitude24 50 to 24 60 and latitude 61 03 to 61 05. At the time of the study, trawl fishing was done 13 times at different times, 8 times during the day and 5 times at night. The total catch during the study period was 12306 kg and 8720 kg were caught during the day (about 71%) and 3586 kg at night (about 29%). The average catch per fishing effort (catch per hour) of the target species was 201 kg (67%) during the day and 63 kg (33%) at night, and the average catch per fishing effort (catch per hour) discard species were 71 kg (28%) during the day and 100 kg (59%) at night (P <0.05). The mean catch per fishing effort (catch per hour) of bycatch fishing species at 18 kg during the day and 9 kg at night were not significantly different from each other (P> 0.05). The Trichiurus lepturus species (64%) had the highest catch of target species, Epinephelus coioides species (53%) had the highest catch of bycatch fishing species and Ray fish (88%) had the highest catch of discard species. The Siganidae and Megalaspis cordyla species, appear to be active during the day and pipe fish, Anguiliformes and Belonidae species of night active.

The study is Considering the importance of the role of benthic communities in evaluating the ecological status of aquatic ecosystems and part of a research project in the southern coasts of the Caspian Sea (depths less of 30 meters) was conducted in 2019. The aim of this study was investigation of the distribution, density and biomass of macrobenthos organisms in the water at a depths of 5, 10 and 30 meters south Caspian Sea. Sampling was seasonaly at eight with using Van Veen Grab. Overall 34443 organisms of Polychaeta including 3 families, 4 genuses and 4 species. The results showed that the highest density at Sefidrood station with mean of 327±27.71 N/m2 and lowest was at Bandartoraman station with mean 77±5.33 N/m2. The highest of Polychaeta was in summer and depth 30 meters with mean 285±26.18 N/m2 and lowest density in spring and depth 10 meters with mean 38±10.81 N/m2. The highest biomass was in spring and depth 30 meters with mean 0.23±0.02 g/m2. The highest species was assigned to S. gynobranchiata with mean 352±19.74 N/m2 and frequency 80%. In general, the results showed that in most seasons of the year, S. gynobranchiata was the dominant Polychaeta species.

the aim of this research was conducted to investigation of rice husk extract on growth performance and expression of related genes (GH and IGF-1) in ozone fish fingerlings. For this aim, the number of 120 pieces of healthy ozone fish fingerlings (50 ± 2.6 g) was purchased and then was randomly transferred in tanks with a water volume of 1000 liters. They were fed for 60 days with different levels of rice husk extract in the basic diet (crud protein: 44.5%) including 0.5 , 1 and 2 g Kg-1 of diet along with a control group (with three replicates) at the rate of 5% of body weight. At the end of the trial, growth performance was evaluated by biometrical assay completely randomly. Also, brain tissue was sampled to investigate the expression of genes involved in growth (GH, IGF-1).The results showed that feeding ozone fish fingerlings with different levels of rice husk extract had a significant effect on the growth performance and the expression of related genes in treatments compared to the control group (p<0.05). So that the best results were observed in treatment fed with 2 g of rice husk extract in per kilogram of diet (p<0.05). In general, the results showed that using rice husk extract was able to improve the growth performance and the expression of related genes involved in growth in ozone fish fingerlings, and the best level recommended in this study was 2 grams in per kilogram of diet.

This research aimed to enrich Artemia nauplii with Easy DHA and Espresso to improve the growth and survival of vannamei shrimp post larvae and transfer them to brackish water (Caspian Sea). 2100 vannamei shrimp post-larval with an approximate average weight of 49.54 ± 2.60 mg and an average length of 1.09 ± 0.07 cm (PL8) were selected. For each replication, 50 vannamei shrimp post-larval were randomly placed in forty-two 20-liter glass tanks (containing 15 liters of water) and were distributed indoors. Post-larvae were fed, including freshly hatched Artemia, Artemia enriched with Easy DHA and espresso, and commercial diet for ten days (in salt water and desalination water). The highest growth rate (weight and length) in the saltwater group was observed in treatment seven (P < 0.05). Also, the highest survival rate in this group was observed in group three, with 71% (P < 0.05). Among the treatments of the brackish water group, the highest growth rate (weight and length) was observed in group fourteen (P < 0.05). The highest survival rate was observed in treatments of nine, ten, and thirteen (P < 0.05). Post larvae of the sea and brackish water showed the highest amount of fatty acid C20-5n3 in treatment three and fatty acid C22-6n3 in treatment two (P < 0.05). Based on the present study's findings, enrichment of Artemia with Easy DHA and Espresso and feeding post larvae with it for nine days can increase survival and resistance to stress (transition to lower salinities) in vannamei shrimp post larvae.

The Environmental variables are considered as important factors determining habitat preference and selection by fishes in the aquatic ecosystem. Therefore, it seems essential to know the habitat requirements of inhabiting species. This study in summer on Kesilian River, one of the considerable sub-basins of the Talar River in the north of country, was selected to investigate the habitat preferences of Kora Barbel (Barbus lacerta) at various ages. According to the diverse habitat characteristics, three sites were selected on the stream, and then samplings were carried out at 211 points using an electroshocker. At each point, environmental parameters including speed, depth, and type of biotic and abiotic substrate were measured and determined. The results showed that this species has different habitat preferences at different ages. General preferences of this species took place in the speed range of 15-76 cm/s and the depth of 45-75 cm. Preference for abiotic and biotic parameters of substrates included "block", "cubble" and coarse and fine particulates organic matter, wood and living parts of terrestrial plants, respectively. Regression logistic indicated that the variables including velocity and abiotic parameters of substrate are the most important factors in presence of this species in the stream. In general, the diverse environmental conditions of the stream have provided different habitat preferences for this species at different ages.

The behavior of rural households for fish consumption was evaluated in the Golestan province of Iran . Data were collected through a designed questionnaire. In the inferential analysis of the research, chi-square, Mann-Whitney, and scoring tests were used for ranking. 51.3% of households are interested in fried fish and 32.7% are stuffed fish and 37.3% and 33.3% of households in these areas supply fish from the place of fishing and harvesting and fish market. About 57% buy less than twice a month and an average of 6.12 kg of fish. 42% of them consumed canned food and their per capita consumption was 37.7 kg. The most important reasons for consuming their fish were one to four quality and freshness, cheapness, cleanliness and hygiene, and nutritional properties and value, respectively... People under 45 years old like the supply of packaged and frozen fish. People with higher income and above 25 million Rials buy fresh, filleted and completely cleaned fish and the opposite group with lower income are more inclined to canned fish. .. They consider the properties and nutritional value of marine fish to be much higher than farmed fish, and they had great skill in distinguishing fresh fish from stale fish. Therefore, there is a possibility of providing a market and supply of processed products to help the economy of rural households in the province to increase fish per capita consumption. However, the possibility of access to marine fish and reducing the price of fish in rural should be provided to increase consumption, and a special study of the consumption of marine and farmed fish in rural areas is recommended.

This study was conducted in order to compare the presence of polycyclic aromatic hydrocarbons in sediments and to compare them in four groups of macrobenthic communities, including gastropods, bivalves, crustaceans, and polychaetes in the north of Persian Golf. Sampling was carried out at 9 stations using a van veen grab along the coastline of Bandar Abbas in March 2018 and August 2019. The average concentration of total PAHs in two sampling periods, regardless of time distribution by station, showed that the refinery has the highest concentration of these compounds, followed by Posht-e-Shahr and Soro. The highest average concentration of polycyclic aromatic hydrocarbons in gastropods belonged to the 3-ring compound Acenaphthene with an average (ppb) of 1117 and the lowest value belonged to the 6-ring compound Benzopyrylene with an average (ppb) of 2. In bivalves, the highest average concentration of the 3-ring compound Acenaphthene with an average (ppb) of 1261 and the lowest value of the 6-ring compound Benzopyrylene with an average (ppb) of 32 was obtained. The highest average concentration belonging to the 4-ring compound Fluranthene with an average (ppb) of 1551 and the lowest value belonging to the 6-ring compound Benzopyrylene with an average (ppb) of 0 were obtained in crustacean tissue. Studies showed that sediments absorb 5-ring compounds, molluscs absorb 3-ring compounds, crabs absorb 4-ring compounds, and reptiles absorb 5-ring compounds more easily.

The excessive growth of the aquaculture industry, in addition to using more natural resources, causes a disturbance to the biological and non-biological balance through effluent releases, and water quality indicators provide the possibility of better management of pollution and direction for targeted biological monitoring. The purpose of this research was to evaluate the nitrogen load of the basin and rainbow trout breeding farm on the water quality of Zarin Gol River in Golestan province, Iran, based on a standard index (WQI) by measuring water quality parameters including: pH, total phosphate, temperature, nitrate, dissolved oxygen, turbidity, and total coliform. Sampling was done seasonally at five stations (before and after the first and second fish farm and 1000 meters downstream from the second fish farm) in 2018. The results showed that the concentration of nitrogen and phosphorus in the River during the six months of fish breeding on the second farm was estimated to be 16.5 tons of nitrogen and 2.9 tons of phosphorus. According to the WQI, the results showed that the water quality values in all the studied stations are 79.7 to 87.8, which indicates excellent water quality according to the descriptive table. It seems that under the current conditions, the Zarin Gol River has the ability to self-purification the effluent of two fish farms with the expected capacity.

Length-weight relationship, length abundance, maturity percentage and growth parameters of green tiger prawn caught using trawl nets in Mond and Dayyer-Nakhilo areas located in Bushehr province during the years 2020 (13 August to 15 February) and 2021 (11 April to 9 September). A total of 658 tiger shrimps, including 420 female shrimp and 238 male shrimp were bioassayed. Based on the carapace length of 43.43 mm in the first sexual maturity of the females, 50.71% (213 specimens) were mature and 49.29% (217 specimens) were immature. Also, the relationship between the total length and carapace length of female shrimps was y=0.3679 x - 2.1648 based on linear regression. The relationship between the length and weight of 420 female shrimps and 238 male shrimps caught showed that parameters a, b, and r2 were 0.0099, 3.057, and 0.92 for females and 0.0115, 2.9962, and 0.912 for males, respectively. Based on the Sturges formula, 10 length classes were observed for male and female shrimps caught. The length class of 108-12.3 cm for both males and females had the highest frequency with 110 specimens (46.22%) and 141 specimens (33.57%), respectively. The results of this study showed that the maximum length of male (16 cm) and female (20.5 cm) caught shrimps was less than the infinite length and more than the optimal length. Growth parameters (Clinf, K, t0) for females were -0.057, 2.1 and 72 (mm) and for males -0.075, 1.7 and 62 (mm), respectively. The values of Z, F and M parameters for females were 9.2, 7.4 and 2.16 and for males 7.58, 5.62 and 1.96. The exploitation rate (E) was 0.77 for females and 0.74 for males. These values indicate overexploitation and fishing pressure in the area. Therefore, it is necessary to implement fishing management approaches in these habitats.

The kutum of the Caspian Sea has long been familiar with the life of coastal people, so that it has played a significant role in the economy of the coastal cities of the south of the Caspian Sea, and the living resources of the Caspian Sea, especially its economic fish stocks, have been seriously attacked in the past few years due to various crises. The study of growth parameters and intra-population structure makes interpretation, analysis and predictions related to the abundance of populations of a species possible, and Sefidrood River, as the most important fishing river of the country in Gilan province, plays a very important role in reproduction and stock enhancement of kutum. It was studied for a period of 10 years (2010 to 2019).The highest average total length and total weight for both males and females was obtained in 2014, which was 44.41 cm and 943.72 grams for males, and 50.49 cm and 1401.98 grams for females, respectively. Other years had significant differences (p < 0.05). The type of growth pattern for kutum population was obtained in 2013, 2014 and 2017 from isometric type, in 2010, 2011, 2012, 2015, 2016, positive allometric type and in 2018-2019 from negative allometric type. The highest value of the condition coefficient was obtained in 2019 and the lowest in 2015 (p < 0.05). The results showed that in all the studied years, total length and total weight also increased with increasing age for the population. The infinite length (L∞) in the populations in the 10-year period was between 73.11-87.74 cm. The range of growth rate (K) in this study for populations was between 0.08-0.19. Zero age index (t0) for populations was between -0.46 until -0.93, and Monro's Phi index (ф) was obtained between 6.18 until 7.28 in populations.