فهرست مطالب seyed ahmad reza hashemi

The molluscs of Persian Gulf and Oman Sea have high nutritional value with high levels of protein, amino acids and fatty acids. Little researches have been done on determining the nutritional value of the identified species. This study was carried out with the aim of evaluating the nutritional value of the sea snail Babylonia spirata in Kanarak Wharf.Thirty sea snails (with an average length of 22±1.12 mm and an average weight of 7.8±0.14 g) from the mud and sand beds of Kanarak wharf (Sistan and Baluchistan province) were kept in cold boxes with powdered ice and transferred to the laboratory. Body chemistry, fatty acids and amino acids compositions were used. The results showed that the amount of protein, lipid, ash, moisture, and dry matter was 18.75, 6.49, 3.30, 70.63 and 29.37% respectively. Total essential amino acids and non-essential amino acids were equal to 15.95 g of amino acids/mg.The nutritional value of snail amino acid content is 60.50% compared to egg. The highest amount of amino acid in snail tissue was isoleucine (4.23 mg/g tissue), valine (3.06 mg/g tissue), lysine (1.10 mg/g tissue) and phenylalanine (1.09 mg/g tissue), respectively. In the analysis of the content of fatty acid groups, it was found that the highest amount among saturated fatty acids was palmitic acid (13.40±0.04%), stearic acid (6.29±0.23%), and heptadecanoic acid (6.17±0.18%) respectively.Among monounsaturated fatty acids (MUFA), eicosenoic acid (EPA, 20.80±0.33%) and palmitoleic acid (PA, 12.16±0.36%) showed the highest amount, respectively. While the highest amount of long-chain unsaturated fatty acids was respectively related to linoleic acid (LA, 20.27±0.24%), linolenic acid (LNA, 10.23±0.25%) and arachidonic acid (ARA, 2.08±31%). Also, the amount of eicosasterenoic acid (ETA) and eicosapentaenoic acid (EPA) was reported as 1.10±0.01 and 1.07±0.23%, respectively.The results of this research showed that the presence of amino acids (isoleucine) and fatty acids (linoleic acid) content, gives more economic value to sea snail B. spirata

In the present study, the exploitation status of Babylon snail was evaluated by sampling four fishing areas of this species in the north of the Oman Sea (Iran) including Pasabandar, Bris, Pozm and Konarak from September 2021 to September 2022. In order to estimate the amount of catch per month, sampling was done by collecting statistics and information from the landing site, by counting at the place and sampling at the time. The amount of Babylon snail fishing effort and catch indicates that Bris and Pozm stations had the highest and lowest catch rate as well as fishing effort (day-boat) at the time of snail harvest (P < 0.05). The average catch per fishing effort post Monson and per Monson time were 183 ± 79 kg and 117 ± 25 kg, respectively (P < 0.05). In general, the fishing status of Babylon snail species has a fishing effort of 4569 days - boat fishing per year and the average catch per fishing effort (CPUE) of each boat is about 150 kg and the average catch per cage is about 0.59 kg. According to the calculations, the average of virgin biomass was obtained 971 (918-1047) tons, the average of maximum sustainable yield (MSY) less than 250 tons and maximum constant yield (MCY) less than 180 tons and total allowable catch (TAC) less from 220 tons, respectively. The amount of Babylon snails catches on the northern waters of the Oman Sea (Sistan and Baluchestan province) is more than 670 tons per year, that its seems to be higher than the optimal catch.

This research looked at the basic information aboutThunnus albacaresfound in the northern part of Oman's Sea, and give useful information on how correctly manage of this resource. During the years of this study)1992and 2022(, over 6000fish were measured and the average length (range) of Yellowfin tuna fish in 1992and 2022was 93±26 (21-157) cm and77±18 (24-175) cm, respectively.The average weight (range) of this species was 9127±1251 (3500-55000) grams in 1992 and 10639±1450 (1100-85000) grams in 2022. The relationship between fork length and total body weight for the year 1992, W=0.014×L2.51(R2=0.83, N=750) and the year 2022, W=0.019×L2.46(R2=0.89, N=703) was obtained.Vonbertalanffy equation for this species in the northern waters of the Oman Sea (Iran)was calculated in 1992 and 2022 respectively as: Lt= 182 (1-exp (-0.39 (t +0.25)) and Lt= 177(1-exp (-0.55 (t +0.18))). The ratio of spawning potential based on length (LBSPR) in 1992 and 2022 were 0.22 (0.20-0.25) and 0.10 (0.09-0.12), respectively. Based on ratio of Pmega< 0.1, Lmean/ Lopt<1andLmean/LF=M<1show considered undesirable. Decrease of the average length, LBSPR index and increase of fishing and total mortality can be a reason for overfishing. The present study showed that the Yellowfin tuna stock has reached 'overfished' status. The findings of this study can assist management and sustainable harvestof this species stocks.

For more than two decades, assessment and monitoring of Oman Sea demersal resources has been carried out using swept area method. The study area starts from western water of Iran to border of Iran and Pakistan in the east of Oman Sea and total study area were divided into 5 sub-areas A to E in different depth layers of 10-20, 20-30, 30-50 and 50 -100 meters. In general, the average amount of biomass has a downward trend in different depths of 2003 to 2021 years(P<0.05). Some species fish such as Otolitus ruber, Pomadasys kaakan, Ray and sharks in fishing composition have decreased sharply and some species fish such as Saurida tumbil, Sphyraenidae, Carangidae and Mullidae in fishing composition have increased. Considering the mentioned conditions, it seems that the amount of demersal resources caught is not in a good condition and measures should be taken to reduce the catch of these fish.

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 aim of this study is to develop different models of aquatic forecasting and try to predict yellowfin tuna catch in the southern waters of the country with minimum possible errors. The average catch (Yi ± S. D) and logarithm of catch (LogYi ± S. D) for the years 1997 to 2021 were 35,378 ± 13,744 tons (95% confidence interval 21,634 - 49,129 tons) and 4.51 ± 0.18 tons (95% CI The confidence interval was 4.33-4.69 tons), respectively. According to the Mann-Kendall test, the average catch has increased significantly during the mentioned period (over the last two decades) (Z = 3.80, P < 0.05).  Different ARIMA combined prediction models (ARIMA, (p, d, q)) were tested based on the AIC index, and the ARIMA model (1, 0, 0) had the best fit with the change trend of yellowfin tuna in the southern waters of the country (AIC =- 24). The predict of yellowfin tuna catch results in the neural network (NN) models was show that feed forward neural networks (FFNN) have better performance than other models and with less error (MAE=0.02 and RMSE=0.03). Also, according to the results of ARIMA time series and neural network models, it can be concluded that feed forward neural networks simulate catch this species fish with higher accuracy than time series models. It seems, forecasting the trend of aquatic catch can be an important tool for fisheries managers and planners for better and sustainable management of aquatic resources and should be given more attention.

The current work aimed to develop a framework for the estimation of the optimized catch limit of the Yellowfintuna(YFT),Thunnus albacaresstock using catch data in the Iranian southern waters.In this study, two methods were employed to determine the biological reference points (BRPs) of this species. Biometry data was collected for 18 years (1993-2019) and the optimized catch limit was estimated using the limited data approaches. In an estimation method of Length-based Bayesian biomass(LBB), the highest length of this species was calculated as 166 (163-169) cm. The estimate of F/M= 1.9 (1.35-2.5) confirms the overfishing of yellowfin tuna, but the estimate of B/B0=0.17 (0.109-0.238) shows the overfishing of the biomass. In an estimation method of length-based spawning potential ratio (LB-SPR), F/M>2.5 is upper the level that probably results in the maximum sustainable yield (F/M= 0.8-1.0). In the present study, the spawning potential level of the population was estimated at approximately 11%, which means over-exploitation of this species so far. The results showed that the exploitation ratio of YFTstock is overfishing (overexploitation) and a decrease in exploitation ratio and fishing effort are proposed. Regarding the condition of yellowfin tuna stock, both LBB and LBSPR methods confirmed each other and there is no big difference between them.

The purpose of this study to develop a framework for investigating the catch trend and estimation of optimized catch limit of the T. tonggol stock by collecting catch data in the Iranian southern waters.  In this research, the information of twenty-five years of catch of this species was prepared and with use of data limited approach and R software, estimation of optimal catch was made. The average catch (Ct) for this study period was 44609 tons (95% confidence interval 38882-53936 tons) and the average catch (R = 0.74, P < 0.05) increased significantly during the study period. Average (maximum-minimum) of carrying capacity (K), current biomass (B), maximum sustainable yield (MSY), biomass of maximum sustainable yield (BMSY) based on Catch-MSY (CMSY) model, Optimized catch-only model (OCOM) model and Zhou-Boosted regression tree models(Zhou-BRT) model was estimated and the mean reference points not show significant difference by statistical tests (P>0.05). This research shows that the annual harvest of Longtail tuna species has reached its maximum amount and no increase in fishing is suggested for this species.

The study of fish in aquatic ecosystems is important from many aspects, including ecology, behavior, protection, and management of water resources, exploitation of reserves, and their cultivation the genus Acanthopagrus includes species with high economic importance and many challenges in their classification. The reason for this is the morphological similarity between a large number of their species. The purpose of this study is to investigate the morphological diversity of 5 species of Acanthopagrus fishes using traditional morphometry, truss system and geometric morphometry in the Gulf of Oman and the Persian Gulf. In the present study, in traditional morphometry17 morphometric charactris and 10 meristic charactris were measured . In the geometric method, 17 landmarks were placed on the images, and then morphological differences between species were subjected to principal component analysis (PCA) and canonical variate analysis (CVA). In the traditional approach,morphometric charactris show the separation of A. arabicus species from two species, A. bifasciatus and A. catenula, meristic charactris performed much better than quantitative charactris and separated most of the species from each other. The number of lateral line scales and the number of scales above the lateral line showed the greatest role in the separation of the members of this genus. Also, the truss approach separated A. catenula and A. bifasciatus species from other species. The geometric method shows the separation of two species, A. arabicus and A. sheim.

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.

The purpose of this study to develop a framework for investigating the catch trend and estimation of optimized catch limit of the P. homarus stock by collecting catch data in the northern waters of the Oman Sea. In this research, the landing catch data of the northern waters of the Oman Sea (Sistan and Baluchistan province) for more than twenty years (based on tons) have been collected from the Iranian Fisheries Organization (1997-2019). The average catch for this study period is 33±6 tons with a 95% confidence interval of 27-39 tons, and the amount of catch increased during the study period (R = 0.37). The average (95% confidence interval) for the intrinsic growth rate (r), maximum sustainable yield (MSY), biomass of maximum sustainable yield (BMSY), and carrying capacity (K) were obtained 0.56 (0.4-0.78) annually, 140 (120 – 170) tons, 156 (95 - 255) tons, 313 (192-510) per year, respectively. Based on the trends of B/BMSY and F/FMSY ratios, it can be said that the increase in fishing mortality and the decrease in available biomass started in 2014 and continues. This research shows that the annual harvest of this species has reached its maximum amount and measures should be taken to reduce the amount of catch and fishing effort.

The Persian Gulf and the Oman Sea contain a variety of aquatic species. Among which, Parastromateus niger (Bloch, 1795), Black pomfret fishes are very important and, one of the tuna fish that has increased its catch in recent years. In this research during April to March 2020, trend catch and demographic characteristics and demographic characteristics of Black pomfret were estimated by collecting information from 4 catchment areas in the southern waters of Oman Sea (Sistan and Baluchestan) including Pozem, Konark, Beries and Pasabandar. In this study, more than 14,000 fish at the research stations were biometric and the growth parameters were infinite length of L∞ = 54 cm, growth factor K = 0.36 (yr-1), natural mortality M= 0.52 (yr-1), mortality and mortality (yr-1), F = 1.27, total mortality (yr-1), Z = 1.79 and exploitation coefficient (yr-1), E = 0.71, and the time zero was -0.39 for the years. This study shows that the annual harvest of Black pomfret stock has reached its maximum and any increase in fishing effort will affect this stock and will reduce the amount of exploitation in the long run.

Awareness of the amount of aquatic stocks in each water source is one of the first and most basic information needed to manage of fishery stocks. The Babylon snail species has commercial and export value and its catch has increased in recent years and has not been studied yet. In the present study, the exploitation status of Babylon snail was evaluated by sampling four fishing areas of this species in the north of the Oman Sea (Iran) including Pasabandar, Bris, Pozm and Konarak from September 2021 to September 2022. Biometric analysis was performed on a total of 2779 Babylonian snail specimens. The mean length (standard deviation) and weight (standard deviation) of total snails were 34 ± 5 in the range of 19 - 64 mm and 12 ± 5 in the range of 2- 66 g, respectively. Growth and mortality indices include infinite length (mm) L∞ = 71, growth coefficient K = 0.35 (yr-1), natural mortality M = 0.5 (yr-1), fishing mortality F = 1.75 (yr-1); Total mortality was calculated Z = 2.25 ± 0.29 and exploitation coefficient E = 0.78. Babylon snails have a recruitment in all months of the year and have two major recruitment peaks during the year. The Production per biomass (P/B) 2.15 ± 0.23 in the range of 2.38 - 1.92 and the average annual production is 12 ± 3 per year in the range of 9 - 15. The present study showed that the exploitation coefficient of this species was not desirable and it should be in order to maintain and sustain fishing of this species, appropriate measures should be considered, including reduction of exploitation.

In this study, the relationship between water physicochemical parameters (sampling of water and soil) and Babylon snail biomass was done by sampling from four fishing grounds of this species in the north of the Oman Sea including Pasabandar, Breis, Pozm, and Konarak from September 2021 to September 2022 by circular cages. The average values of different physicochemical parameters (pH, salinity, turbidity, TOM, dissolved oxygen, and sand and silt) and different nutrients (nitrate, phosphate, ammonia, and nitrite) in the before and after seasons (monsoon) did not show a significant difference (p>0.05) through one-way variance analysis (between several periods) comparison of averages. Temperature and silt parameters from different seasons (before and after monsoon) had significant differences (p<0.05). Multi-layer artificial neural network was used for the correlation among the snail biomass, physicochemical parameters, and water nutrients and it showed that Temperatures and Nitrite were the most impact parameters on (snail biomass). From September to November, the highest catch rate was observed and it was the main season of Babylon snail fishing in Sistan and Baluchistan region due to the decrease in the water temperature and increase in the nitrite content. This study can be considered for fishing sustainability, basic management in exploitation, and a better understanding of the biological and demographic characteristics of this snail species.

The impact of the covid-19 pandemic on job opportunities losing and life quality reduction of the traditional fisherman community of Iran in order to guide the interventions to maintain the employment and provide the livelihood of the fishing communities were studied in 2021 through an online electronic questionnaire. The data collection was done in a simple random way by sending the link of the questionnaire to the fishing community using the WhatsApp social network. The data quantification method was used to describe the results. A total of 693 questionnaires were received, of which 98.6% were men and 1.4% were women. On the other hand, 76.9% of the interviewees were young people under 50 years old. The results showed that 61.3% of the interviewees confirmed that at least one of their family members lost their job, 84.5% stated that their income decreased, and about 83.2% declared that they had lost their jobs for more than a month due to the spread of the Corona virus. Staying at home to avoid being exposed to the disease as the main reason for unemployment was declared by 65.3% of interviewers. Almost 32% of interviewees stated that they have the possibility of finding an alternative job, and among them, free labor jobs with 42.5% and agriculture with 25.8% were the most important alternative ways of generating income. The outbreak of the Covid-19 pandemic has negatively affected the livelihood of the Iranian fishing society, 89.3% of the fishing society was generally worried about preparing food during the Covid-19 pandemic period, and 59.6% were not able to provide their health and medical items. The results of this research recommend the intervention measures of the government regarding the livelihood of the fishing community during unemployment due to crises.

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 60and latitude 61 03 to 61 05. At the time of the study, trawl fishing 13 times was done 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 study of target fish catch in depth different showed that with increasing depth, the target fish catch increased and the highest percentage of target fish catch was seen at depths of more than 120 meters (P <0.05). The rate of discard fish species was about 40% and its rate was more at night than day time and the discard fish species CPUE rate of trawlers showed in the night more than daylight time (P <0.05). In general, it seems that discard fish species ratio of trawler in the night hours is more than during the day and this rate at depths less than 100 meters is higher.

Examining the important relative index of IRI. Index of food preference Fp and gastric emptiness index of CV in this fish showed that this species is a gluttonous fish and the amount of gastric index of this species is calculated in spring and the lowest in summer.CV emptiness index increased from spring to summer, which reached its maximum in summer and decreased after summer, indicating that fish do not feed in summer and most feed in winter. Stomach index and liver index reached the highest in spring and the lowest in summer.In the stomach contents of this species, in order of priority, different groups of bony fish, then crustaceans such as crabs and shrimp were seen, but the largest volume of stomach contents was found in bony fish such as quince. بزماهی. Sardines and squid and pentagonal fish formed in this species. Of the total number of fish studied, three dietary groups of fish, crustaceans and cephalopods formed this species.Index of gastric emptiness (CV) showed that in large mane mane fish, the highest value of this index is in summer and showed that this species in this season, which is its breeding season, is very low in appetite and in spring and autumn It is relatively gluttonous and reaches its minimum in winter and shows a lot of nutrition and overeating of this species in this season.

For more than two decades, assessment and monitoring of Oman Sea demersal resources has been carried out using swept area method. The study area starts from western water of Iran to border of Iran and Pakistan in the east of Oman Sea and total study area were divided into 5 sub-areas M to Q in different depth layers of 10-20, 20-30, 30-50 and 50 -100 meters. In general, the average amount of biomass has a downward trend in different depths of 2003 to 2021 years. Due to the changes in the average biomass at different depths, it can be said that the average biomass at depths of less than 20 meters has decreased. Average biomass of depths less than 20 meters have decreased significantly from about 14 thousand tons in 2003 to about 1.5 thousand tons in 2021 (P<0.05), and benthic biomass accumulation has shifted from coastal and shallow areas to deeper areas. Also, average catch per unit area of different areas had a decreasing trend in 2003 to 2021 and usually regions O and Q had higher values than other regions in different years (P <0.05). Some species fish such as Otolitus ruber, Lethrinidae, Ray and sharks have decreased sharply and some species fish such as Nemipterus japonicus, Saurida tumbil and Sphyraena sp. have increased in fishing composition. Considering the mentioned conditions, it seems that the amount of demersal resources caught is not in a good condition and measures should be taken to reduce the catch of these fish.

In the present study, the population characteristics of Spiral Babylon, Babylonia spirata, were evaluated by sampling at four sites in the northern Oman Sea, Iran, including Pozm, Konark, Beries, Pasabandar from March 2021 to March 2022. A total of 2779 Babylonian snail specimens (1489 males, and 1290 females) were measured and about ten percent of the specimens were described. The mean length and weight of males and females were 36±5, and 32±5 mm and 14±6, 10±4 g, respectively. Growth and mortality indices for females and males including infinite length (L∞ = 68 and 76 mm), growth coefficient (K = 0.54 and 0.3 (yr-1)), natural mortality (M= 0.7 and 0.4 (yr-1)), fishing mortality (F = 2.30 and 1.79 (yr-1)), total mortality (Z = 3 and 2.19 (yr-1)) and exploitation coefficient (E = 0.77 and 0.82 (yr-1)) were estimated. Based on the LBSPR assessment model, estimated to be about 0.3, and a ratio of Pmega<0.1, Lmean/Lopt <1 and Lmean /LF=M<1 show considered undesirable. The present study showed that the Spiral Babylon stock has reached 'overfished' status.

Babylonia spirata is one of the important commercial oyster species in the world. The ecological basis of the habitats of this mollusk in the coastal waters and in the areas of the continental plateau is a significant help to fishermen and operators. Therefore, to identify the ecological characteristics of the Babylon Sea snail habitat in the northern waters of the Oman Sea, water sampling was done to determine temperature, pH, salinity, dissolved oxygen, nutrients, turbidity, and sediment, the total organic matter and the type of substrate, Babylon species to determine CPUE was done monthly from September 2021 to May 2022. The results showed that the average water temperature during the study period was 27.79°C in Konarak, 26.99 in Pezam, and 28.5 in Pasabandar and Bris. The average salinity in Kanarak, Pozem, Bris, and Pasbandar stations were 39.33, 26.99, 39.25, and 39.25 g/L, turbidity 5.48, 2.5, 7.25 and 7.25 FTU, acidity 8.25, 8.22, 8.18 and 8.18, DO 6.6, 7.06, 6.97 and 6.97 mg/l, nitrate 1.35, 1.16, 1.11 and 1.11 mg/l, nitrite 0.04, 0.02, 0.055 and 0.055 mg/l, ammonia 0.05, 0.19, 0.01 and 0.01 mg/liter,  phosphate 0.37, 0.23, 0.25 and 0.25mg/liter, and the organic matter 0.64, 0.52, 1.67 and 1.67%, respectively. The results revealed that nutrients play an important role in the density of Babylon in this region. With the increase of nutrients, the density of Babylon increases with a sharp peak and reached the maximum in October and November, and after that, with the decrease of food, the density decreases. Based on multiple linear regression analysis, the nitrite was highly related to the amount of catch per unit effort of the Babylon Sea snail.

In the present study, the Life-history and population dynamic characteristics of Holothuria leucospilota were evaluated in the Iranian part of the Oman Sea by sampling at nine sites, including Ramin, Kachoo, Aliabady, Beries, Beries plane, Pasabandar, Tis, Pozm and Gurdium from March 2017 to March 2018. Biometric data of 862 specimens were obtained, and the growth and mortality indices, including infinite length (L? = 50.5 cm), growth coefficient (K = 0.51 (yr-1)), growth performance index (? = 3.11), natural mortality (M = 0.94(yr-1)), fishing mortality (F = 0.56 (yr-1)), total mortality (Z = 1.50±0.12 (yr-1)) and exploitation coefficient (E = 0.36 (yr-1)) and time zero (-0.27) were calculated. Mean of relative production per recruitment (Y' / Rp), relative biomass per recruitment (B' / Rp) and exploitation rate (U) of the studied population of H. leucospilota were 0.02, 0.30, and 0.28, respectively. Mean GSI and maturity stage indicated that the spawning seasons were June (spring) and December (autumn). The mean size at first sexual maturity (LM50) was 246 mm for males, 220 mm for females and 225 mm for both sexes. The results of the current work showed that the studied H. leucospilota stock had not yet reached to overfished’ status.

In the present study, population characteristics of Sphyraena jello were evaluated by sampling fish at five fish landing sites in the northern Oman sea (Iran) including Beris, Ramin, Pozm, Konarak and Jask from April 2020 to February 2021. The biometric analysis was performed on more than 301 fish. Growth and mortality indices were calculated including infinite length (L∞ = 155 cm), growth coefficient (K = 0.55 (yr-1)), growth performance index (Ф=4.14), natural mortality (M= 0.74 (yr-1)), fishing mortality (F = 1.46 (yr-1)), total mortality (Z = 2.20±0.29 (yr-1)) and exploitation coefficient (E = 0.67 (yr-1)). Relative production per recruitment, relative biomass per recruitment and exploitation rate of S. jello were Y'/Rp = 0.05, B'/Rp = 0.18. The present study showed that the stock conditions of this species is under of moderate.

The purpose of this study was to investigate the catch trend and estimation of the optimized catch limit of the Scomberomorus guttatus (GUT) stock by collecting catch data in southern Iranian waters. In this study, two methods were used to determine the biological reference points (BRPs) of Indo-Pacific king mackerel in southern Iranian waters i.e. the Persian Gulf and Oman Sea. Catch data was collected for 23 years (1997-2019), and the optimized catch limit was estimated using a limited data approach and R Software. The average catch (Ct) for this period was 5123 tonnes (95% confidence interval 4026 -6218 tonnes), and it had significantly increased over the past two decades. The average (maximum-minimum) of carrying capacity (K), maximum sustainable yield (MSY), the biomass of maximum sustainable yield (Bmsy), current biomass (B) and fishing mortality of maximum sustainable yield (Fmsy) were obtained by the Depletion-Based Stock Reduction Analysis (DBSRA) and Catch- maximum sustainable yield (Cmsy) models. The Bmsy and K in two models showed no significant difference from the one-sample t-test at P>0.05. The results revealed that the exploitation ratio in the Indo-Pacific king mackerel stock is full fishing (full exploitation), and do not suggest an increase in exploitation ratio and fishing effort are proposed.

In the present study, population characteristics of Scomberomorus commerson were evaluated by sampling fish at five fish landing sites in the northern Oman Sea (Iran) including Beris, Ramin, Pozm, Konarak and Jask from March 2017 to March 2018. The biometric analysis was performed on more than 11000 fish specimens. Growth and mortality indices were calculated including infinite length (L∞= 165 cm), growth coefficient (K= 0.5 (yr-1)), growth performance index (Ф= 4.13), natural mortality (M= 0.75(yr-1)), fishing mortality (F= 2.49 (yr-1)), total mortality (Z= 3.24± 0.15(yr-1)) and exploitation coefficient (E = 0.77 (yr-1)) as well as length time at time zero (-0.2). Relative production per recruitment, relative biomass per recruitment and exploitation rate of S. commerson were Y'/Rp= 0.06, B'/Rp= 0.32 and U= 0.65, respectively. The Pobj value is <1, and Popt and Pmega >0, the fishery show considered undesirable. The present study showed that the narrow - barred Spanish mackerel had undesirable stock condition and fish stocks have reached 'overfished' status. Therefore, specific measures should be taken to reduce catch and fishing effort.

In this research, trend catch and demographic characteristics and demographic characteristics of Longtail tuna (T.tonggol) were estimated by collecting information from 4 catchment areas on the coast of Hormozgan province including Kang, Salakh, Parsian and Jask. In this project, more than 14000 fish at the research stations were biometric and the growth parameters were infinite length of L∞ = 137 cm, growth factor K = 0.41 (yr-1), natural mortality M= 0.63(yr-1), mortality and mortality (yr-1), F = 0.49, total mortality (yr-1), Z = 1.12 ± 0.16 and exploitation coefficient (yr-1), E = 0.43, and the time zero was -0.26 for the years. Relative production per recruitment, relative biomass per recruitment, exploitation rate and average annual standing stock for kawakawa species were estimated Y '/ Rp =0.03, B' / Rp = 0.36, U= 0.38, respectively. This study showed that this species has moderate vulnerability and medium stock conditions, and also, exploitation ratio of this species stock is under fishing.