علی سالارپوری

The present study was carried out in the fishing grounds of small pelagic fish on Qeshm Island (namely Ramcha, Souza, Messen, and Salakh) from September 2022 to June 2023. Field sampling was performed by double-boat purse seiners and conducting 57 netting. The length, height, and mesh size of purse seines were 300 m, 50 m, and 10 mm (STR). Data of date, time of setting, location, and weight of target species and bycatch were recorded for each setting net. The mean CPUE (±95% CI) of small pelagic fish was overally obtained at 991.23 ± 157.14 kg per set. This was 1300 ± 364.01 for Salakh, 1246.88 ± 295 for Ramchah, 669.23 ± 214.20 for Messen, and 587.5 ± 155.71 for Souza, which there was a significant difference between Salakh and Ramcha compared to Souza and Messen (P<0.01). Also, the mean CPUE (±95% CI) of target catch for warm and temperate seasons were 1227.42 ± 224.11 and 709.62 ± 174.20 kg per setting net, which was significantly differ (P<0.01). The maximum and minimum of occurrence percentages were attributed to anchovy (with 100%) and Trichiurus lepturus (with 1.75%). The highest and lowest of mean CPUE (±95% CI) for bycatch species/groups, were related to the Trichiurus lepturus (1.75 ± 3.51) and Dasyatidae (0.07 ± 0.10) kg per setting. Given that fishing efforts have increased in recent years in the region, the estimated values of CPUE for target catch were smaller than in previous studies. Therefore, the fisheries managers must take immediate action to optimize the ongoing fishing effort.

Coastal areas represent the most vulnerable regions of the ocean. Thus, the identification and estimation of sedimentation rates in the sensitive coastal habitats of Qeshm and Lark islands were conducted during 2022-2023. The diving team identified three habitats consisting of natural structures in the north of Larak Island, characterized by the predominance of Acropora sp., and one habitat featuring flora and fauna originating from human-made structures (Doha Qeshm Jetty). These habitats, resembling those on Larak Island but on a smaller scale, were mapped using ArcGIS software 10.1. Three sediment traps were placed at 500-meter intervals in each station to cover each habitat comprehensively. The minimum and maximum sedimentation rates were measured at Larak Islands (St3) with 28 and Doha Qeshm Jetty with 196 (g/m2/day), respectively. Additionally, the minimum and maximum concentrations of suspended substances in the water column, ranging from 9.44 to 21.31 (mg/lit), were observed at these two stations during autumn. The freshness of Acropora sp. served as an indicator in all four habitats, potentially reflecting either the negligible impact of sedimentation rates on communities or the resilience of these communities to sedimentation during the study period

The covid-19 disease caused millions of people in the world to face a food supply crisis. This research was planned and implemented to investigate the impact of the spread of this disease on the fisheries activities of Iran as one of the branches of food supply. The operation of collecting research data through (1) designing general and specific questionnaires, distributing them throughout the country and completing them by fisheries activists in the areas of shrimp farming, coldwater and warmwater, fishing communities, and seafood processing centers of different provinces, (2) gathering information, directives, and necessary data such as the production statistics of the Iranian Fisheries Organization, and (3) a review of the research and actions carried out in other countries. The average reliability of 1044 completed questionnaires was determined as 0.81 based on Cronbach's alpha. The results showed that during the outbreak of the disease, providing inputs and raw materials for growers and processing factories was more difficult (with an average of 65±3%) and more expensive (with an average of 56±5%). The domestic and international restrictions imposed during the quarantine period can be considered as one of the main factors for the difficulty in providing raw materials. In this context, 79% of these people believed that the transportation of raw materials was more difficult these days and affected the supply of the product. The decrease in demand and the increase in the cost of production increased the amount of storage of the manufactured product, which increased the risk and cost for the producers. 70% of the respondents have observed and announced the concern about disease transmission by fish and the decrease in demand among consumers. In the field of employment and economy, the increase in the cost price of the produced product was observed to a higher extent in aquaculture sectors and seafood processing factories. Instead, the fishing community reported the highest rate of job loss among the research target groups. 80% of the production sectors announced that their income decreased during the outbreak of the disease. Also, the results of this research showed the reduction of workers and employees of the production sectors in all groups during the outbreak of the disease. In general, about 78% of the audience announced that the fisheries activities of the country were affected by the negative effects of the coronavirus disease. According to these results and the short-term impact of this disease, among the strategies to deal with crises, the strategy of endurance for similar crises is proposed. To increase the resistance of the country's fisheries sectors in similar cases in the future, solutions and measurements have been proposed such as classifying fisheries activities as vulnerable businesses, developing assistance programs and emergency operational packages, implementing promotion and information measures, regional management in the provinces to meet the needs of the markets, extending, automatic renewal of farm exploitation licenses, the strengthening and development of cold storage plants and processing factories, the necessity of immediate support for local fishermen, and the expansion of online methods of selling aquatic products.

Trichiurus lepturus is one of the most important and commericial species in the Persian Gulf and Oman Sea.In order to come up with the responsible fishing pattern,there was a need to identify  reproduction characteristics. Data were collected randomly from April 2019 to February 2020 from six major artisanal fish-landing sites in Hormuzgan Province (Bandar Parsian, Bandar Kong, Qeshm Island, Bandar Abbas, Bandar Sirik and Bandar Jask). In the detection of sexual stages, the 5-stage key of sexual maturity was used at the macroscopic level. In determining the spawning season, the gonado-somatic index(GSI) was used and its comparison in different months. The lowest GSI of female fish was in September (1.2). The highest GSI of male fish was determined in December with a value of 3.1 and after that in May 2.6. Examination of the GSI and reproductive stages showed two main spawning periods in the middle of spring and late autumn. Different sexual stages were seen in all months of the year, which indicated the batch spawning strategy in T. lepturus. During different months, significant differences in the sex ratio were observed, but during the investigation and in total, no significant difference was observed between the female: male sex ratio in the expected ratio of 1:1.The length at first maturity obtained 78.7 cm total length. It is necessary to ban fishing during the spawning season in order to protect the stocks of this species.

The aim of this study was to determine the catch composition differences (morning and evening) during the fishing season of ribbon fish (Trichiurus Lepturus Linnaeus 1785) in the winter of 2020 from the Hormozgan province. The fishing operation was carried out by a mid-water trawler for a week from 6 am. to 6 pm. The average duration of each hauling was 4 hours and the depth of hauling was recorded between 58-68 meters. The ship was equipped with a trawl net with a 41-m head rope and a 75 mm stretched mesh size in the codend. Results of 21 hauling, 23 fish species belonging to 17 families were identified. The frequency of target fish (ribbon fish) was calculated 12719 fishes, with total catch of 21423 kg and CPUE of 1020.14 kg/hauling. The total by-catch was recorded 1828.28 kg, and CPUE of 87.10 kg/hauling. There were no significant differences between total catch of target fish, total by-catch in the morning and evening time, also CPUE and CPUA of target fish(p>0.05). The highest participation rates of fishes were croakers (4.85%), wolf-herring (3.03%), king soldier bream (2.65%), four-finger threadfin (2.59%), queen fish (2.50%), barracuda (2.29%), lizardfish (2.22%), pick-conger (2.01%), king mackerel (1.93%) and trevally (1.85%) respectively.

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.

Standing biomass of coral fish was estimated by the Underwater Visual Census method(UVCm) and belt transect in five stations (St.) (dead corals, continuous and developed reefs, discrete and undeveloped reefs, Acropora spp. in small amounts and rocky reefs), in Larak Island from Sep.2020 to Apr.2021seasonally.The maximum and minimum of standing biomass was estimated  908.79 (Kg/Km2) and 235.85 (Kg/Km2) in the Abbas St. and Arabha St. respectively, also the maximum of coral fish standing biomass belonged to Scarus ghobban with 703.99 (Kg/Km2). The maximum of average (standard deviation) was estimated for the Jetty St.(Kg/Km2)16.36(± 4.3) (Feb.2021), and the lowest value at Ghail St. 1.4 (± 1.96) (Kg/Km2)(Sep.2020), also confidence interval of these estimations from bootstrapping simulations (n=2000) was calculated(95%). The results of one-way analysis of variance, Tukey's test, comparing the standing biomass of coral-fish (temporal and spatial analyses), was concluded differences in the most of seasons and stations (P<0.05), and the highest of standing biomass belongs to cold seasons of the year(Oct.2020, Feb.2021) and the lowest of them in the warm seasons(Sep.2020, Apr.2021) is estimated. The study of coral fishes showed although the bleaching event in the Persian Gulf has destroyed the habitat of coral fishes, but the dead corals are covered with microalgae, rocks, developed reefs and a few colonies of living corals (Acropora spp.) at depths above 10 meters have been able to play the role of their habitat. Furthermore, the type of substrate cover, the integrity of evolution reefs, being sheltered from waves and winds, and being away from sources of stress have influenced more than the size of the habitat on the coral-fish stocks of the Hengam Island.

In this research, the frequency of coral fishes from Hengam Island were studied seasonally from summer of 2020 to the spring of 2021 by Underwater Visual Census (UVCm) and belt transect method. A total of 38 species were identified in five selected stations, of which 31 species were herbivorous fishes,  Pomacentridae and Labridae families had the highest frequency with 7 and 4 species. The abundance of herbivorous fish Thalassoma lunare was estimated at 80(±71) number per square kilometer in station two. In addition, two species of parrotfish (Scarus persicus and Scarus ghobban) were the most frequent in all stations. The highest seasonal frequency of herbivorous fishes was recorded at station 2 in winter 58(±12) numbers per square kilometer and the lowest at station 3 in summer 5(±21) numbers per square kilometer. The seasonal abundance of herbivorous fishes were significantly differ between stations, except in summer (p<0.05). The temporal and spatial changes in the abundance of herbivorous fish in the stations indicate the importance of selective performance of fishes for ecological niche. In this regard, the role of functional redundancy is more effective than the role of functional complement among these fishes in the biological future of the coral communities of Hengam Island. Therefore, it is recommended to protect the coral fish stock of the island.

Estimation of coral fishes biomass is needed as a basic benchmark for assessing the ecological status and fishing potential of coral reefs. Different methods are used to sampling the biomass of these communities, that direct observation is one of the preferred methods with respect to the non-destructive advantage. The purpose of investigation was to estimation standing biomass of coral fishes by Underwater Visual Census method (UVCm) in Abu-Musa Island seasonally from October 2019 to September 2020. also confidence interval was calculated of these estimations from the bootstrapping test (95%). Standing biomass of Coral fish and their confidence interval (95%) by bootstrapping simulation (n=479) were determinated 2923.6 kg., 4576.2 kg, and 1645.4 kg for the stations one, two and three respectively. The difference in the biomass standing of coral fish in three station could be related to the lack of differences in the amount of developed reefs, coral communities and significant differences in habitat availability.  Also, the standing biomass of coral fishes in the Abu-Musa Island are limited, that can be attributed to their low habitat, shortage of carrying capacity and the short life of the Persian Gulf basin, and stress that occurs in the ecosystem, especially bleaching events, that need more study in the future.

This study was performed in order to the optimization mesh size of Trichiurus lepturus´s gillnet-fishing in Hormozgan province. At first linear relationships between the total length and the different parts of the body of the Ribbonfish were obtained. In order to evaluate the efficiency and determine the appropriate mesh size, the classification of fish caught by this method was compared with the length at first maturity. The percentage of fish caught in different parts of the body was investigated. By using the length at first maturity of this species and proportion coefficient the optimal mesh size was obtained. More than 57% of the fish were caught in the head (around gill) as the highest part of body fish. The length modes of the various parts of the ribbonfish, including head (gilled), body, snout(snagged) circumference and entangled, were in the total length classifications of 50-55, 65-70, 65-70 and 80-85 cm, respectively. The proportion coefficient was equal to 0.036 and the optimal internal mesh (knot to knot opposite) was calculated to be 57 mm. Considering that more than 71% of the ribbonfish caught with common gillnets have been in sizes less than the length of maturity (78.7 cm total length), eliminating these gillnets and using the optimized mesh nets that proposed this research study,  reduces immature fish in the fishing.

One way to predict how marine ecosystems will react to climate change is to use the time series data. Considering the various economic and ecological values ​​of marine species, and that the demographic dynamics of these species depend on two factors of climate variability and human activities, it was decided to investigate the time series of the data and conduct the present study on catfish storage considering the export value and the role of predators in the ecosystem And change in stock can affect dependent populations. The population vulnerability of these species was investigated by climate change and time series data. In this study, the relationship of fishing time series data on fishing effort unit (CPUE) of catfish from 2007 to 2018 monthly with environmental data including: sea surface temperature, chlorophyll a as well as evaporation rate, rainfall, wind speed and air temperature Using regression methods, neural network and decision tree were studied in the waters of the Persian Gulf and the Gulf of Oman. The results showed a decrease in catfish stocks in the waters of Khuzestan and Sistan-Baluchestan provinces and a steady trend in the other two provinces. In Khuzestan waters, catfish CPUE showed a significant relationship with wind speed and in Bushehr waters with chlorophyll-a, Hormozgan with evaporation and in Sistan - Baluchestan air temperature had a significant relation. Considering the resilience of the mentioned environmental factors and the continuation of the climate change process, it seems that in order to sustainably exploit the fish, environmental factors should be considered.

Population dynamics of Skinnycheek Lanternfish Benthosema pterotum (Alcock, 1890), in the Iranian waters of Oman Sea from April 2019 to March 2020 were studied. A total of 2893 individuals were sampled and used for analysis. Total length ranged from 21-60 mm and the average length was 39.4 mm. More than 84% of the samples were between 33-45 mm TL. The length-weight relationship was obtained TW= 0.00008 TL 2.379 and shown negative allometric growth. The asymptotic length (Loo) and growth constant (K) were estimated at 63 mm and 1.6 yr-1 respectively. Also, tmax and t0 were calculated 1/73 and -0/15 yr -1 respectively. VBGE was calculated Lt = 6.3 ( 1 – e -1.6(t+0.15)). The coefficients of total mortality (Z), instantaneous natural mortality (M), and fishing mortality (F) were estimated as 6/65 yr-1, 2/62 yr-1, and 4/03 yr -1 respectively. Size at first capture (Lc) was estimated at 35.67 mm (TL). The exploitation rate (E) was estimated as 0/60 yr -1.

This study uses data of 5 Iranian industrial purse seiners that fish on free school tuna species in the Oman Sea. The catch data from 2015 to 2019 in the Oman Sea waters were used. The essential fish habitat of Thunnus tonggol was modeled using Satellite remote sensing (HYCOM. and MODIS). Redundancy analysis (RDA) was applied to provide a preliminary view of relationships between fish presence/absence and environmental variables, followed by the application of the Generalized Additive Model (GAM). According to GAM the presence/absence of T. tonggol is related to Latitude, Sea Surface Temperature (SST), Sea surface current velocity, and sea surface salinity (SSS). EFH maps were generated using GAM model based on the probability of the presence of T. tonggol. Latitude 23N to 25N degrees and longitude 57E to 60 E degrees are the preferred habitats of T. tonggol that are distributed in high density in these areas and indicate the habitat of this species in the continental shelf and coastal waters. Based on the analysis the distribution and density of T. tonggol on the east side of the Oman Sea Iranian waters, from Beris to Gwatar Bay, could be neglectable. Based on the results of the present study, it seems that, although, the relationship between chlorophyll-a concentration, sea surface height (SSH) and distribution, of T. tonggol is statistically significant, still the Latitude, Sea Surface Temperature (SST), Sea surface current velocity, and Sea surface salinity (SSS are the most important factors affecting the abundance of this species in the region.

In this research, the relation between the time series Carangid fishes (Carangidae) CPUE data in Sistan-Baluchestan waters with the environmental effective data including sea surface and air temperature, chlorophyll a, evaporation rate and rainfall as parameters of climate change indicators have been studied monthly during 2007 – 2018. GLM and GAM regression were used for data analysis. The results showed significant decrease in carangid species. In this regard, the two factors of SST and air temperature have had an increasing and both SST and air temperature showed significant relationship with Scomberoides commersonianus and other carangid species CPUE stocks. Finally, it seems that in order to maintain the carangids fish stocks due to the various effects of climate change and environmental factors, and human activities particulary, need to reform fisheries regulatory management.

The reproductive biology of Indian halibut, Psettodes erumei, a commercially valuable flatfish species, in the northern Persian Gulf and Oman Sea was studied. A total of 433 specimens were collected monthly from October 2016 to November 2017, and their length, weight, sex, gonad and liver weight, and maturity status were recorded. Monthly variations in Gonado-somatic index showed two obvious peaks in the spawning period in both sexes. Observations from the seasonal maturation curve, the frequency distribution of the female gonadal development stages and the condition factor confirmed recent findings that the spawning periods have two peaks, a higher peak in April-May (spring) and a lower peak in October (autumn). The size at first maturity of females was estimated to be 38.20 cm in total length. The absolute fecundity ranged from 18072 to 332171 eggs while the relative fecundity ranged from 22 to 161 eggs/g. Absolute fecundity was positively correlated with body related parameters (total length/weight) and with gonad weight. Combined, the information provided in this study could be useful for resource managers to set seasonal closure during peak spawning periods and implement minimum size limits above the size at first maturity to let the fish spawn at least once before capture.

Significance of climate change trend in the period of 22 years and the effect of climatic variables on CPUE of pelagic fishes (sardines and anchovies) in three areas: Jask port, Lenge port and Qeshm were studied. Three categories of data including fishing, satellite and meteorological data were processed and analyzed over a period of 22 years (1997 to 2019). Satellite data related to water areas were used to obtain information on sea surface temperature (SST), sea surface chlorophyll (SSC) and photosynthetic active radiation (PAR) variables. Information about meteorological data including wind speed, rainfall and minimum and maximum temperatures were received at 3 offshore and coastal stations. CPUE values ​​were significantly different in the three study areas. The most significant changes were observed for the mean maximum temperature and minimum temperature of the months. So that in each of Jask and Lenge regions in 6 months of the year and in Qeshm region in 9 months of the year, the trend of maximum temperature changes in the desired time period has increased significantly. During the period, the average monthly minimum temperature of 3 months of the year in Jask region, 6 months of the year in Lenge region and 10 months of the year in Qeshm region has increased significantly. The fishes of Qeshm and Lenge regions showed high overlap with each other, while the fish of Jask region showed a more distinct difference than the other two regions in the PCA diagram. The relationship between CPUE changes and environmental parameters was almost the same for both species. In all models, chlorophyll A and rainfall were the most significant and important variables affecting.

Auxis thazardis one of species of scombridae family in the Persian Gulf and Oman Sea. In order to come up with the responsible fishing pattern, there was a need to identify some of characteristics and population dynamic parameters. Data were collected randomly from three major artisanal fish-landing sites Bandar Sirik, namely Bandar Abbas and Bandar Lengeh in Hormozgan Province, from April 2016 to March 2017. The average fork length estimated 33.9 cm. The "a" and "b" parameters in Length- Weight relationship were estimated 0.000002 and 3.3 respectively and showed that A. thazardhas allometric growth. The growth parameters of L∞, K and t0 were computed 53.2 (cm), 0.8 (1/year) and -0.17 year respectively. The fork length attained at the end of 1, 2 and 3 years to be 32.3, 433.8 and 48.1 cm respectively. Growth performance index calculated 7.7 which was in agreement with the finding of the other studies. Total mortality, natural mortality and fishing mortality were estimated 2.45, 1.03 and 1.42 (1/year) respectively. The Fopt and Flimit as biological reference point were calculated 0.52 and 0.68 (1/year) respectively. The exploitation ratio was estimated 0.58.

Bleaching phenomenon was observed in coral communities by Coral Watch method and Photo-transect in Hendorabi Island in Sep.2016.Coral health indices were estimated E1 (complete whitening), E6 (Complete health)and E4 (whitish) for Acropora spp., Hydnophora spp. And Hydnophora spp., also temperature was measured 33.1 ° C around coral colonies. The results of this study showed that the colonies of branching corals are completely whitened, but massive corals can withstand environmental temperature stresses, although some of them have an E4 index and, it is more critical to assume that these species can not relieve themselves of environmental temperature stresses. Since the coral ecosystem, especially the branching coral, has ecological and fishery value for the ornamental fish and larvae of some commercial fish, so health monitoring of the corals is recommended in order to environmental management.

Indian halibut, Psettodes erumei is the single member of family Psettodidae recorded in the southern waters of Iran (north of the Persian Gulf and Oman Sea). In the present study, the feeding habit of this species was investigated. The specimens were collected monthly from October 2016 to November 2017 by shrimp trawl from three sampling sites along the northern parts of the Persian Gulf and Oman Sea (Hormozgan Province, Iran). For the diet analysis, the stomach contents of 433 individuals were analyzed. Of these, 277 were empty (VI=63.97%) which varied significantly throughout the study period. Feeding intensity of both sexes was high before the gonadal maturation peak; during the period when a maximum percentage of fully mature individuals were present, the feeding intensity was found to be low. The overall diet showed that Indian halibut is mainly a piscivorous carnivore and Teleostei were the most frequent and important food group in the diet (%F=48.08, %IRI=98.44). Crustacean and Cephalopods constituted a small portion of the diet (%F=5.77 and 1.92, respectively) and were of minor importance (%IRI=1.33 and 0.23, respectively). Diet composition showed no significant variation in relation to season, fish size and sex and only some significant differences were observed in their frequency and numerical percentage. The trophic level for this species was calculated 4.4. The present study provides partial information on feeding habits of Indian halibut, of prime importance for the fisheries management and also helps to understand the trophic role of fish in relation to other species in the ecosystem.

Population parameters of Common silver-biddy (Gerres oyena) were studied in Hara Biospher Reserve from September 2016 to August 2017. All fishes were sampled by boat trawl, beach seine and trapping barriers. Growth parameters were determined using the monthly length–frequency data. The Mean total length was calculated 8.5±1/35 cm for Common silver-biddy. The value of L∞ and K were calculated 18 cm and 1.5 yr-1 respectively. The rate of natural mortality (M) were estimated 2.68 yr-1. The length-weight relationship were determined as W= 0.0088 L 3.21 and W= 0.00887L 3.21 for Common silver-biddy. Results showed these fishes were juvenile and emphasized on supporting roles of creeks for Gerridae as nursery ground.

Euthynnus affinis is one of the most commericial tuna species in Northern of the Persian Gulf and Oman Sea. In order to come up with the responsible fishing pattern, there was a need to identify some of characteristics and population dynamic parameters. Data were collected randomly from three major artisanal fish-landing sites Bandar Jask, Bandar Abbas and Bandar Lengeh in Hormozgan Province, from April 2015 to March 2015. The average of fork length estimated 60.1 cm. The "a" and "b" parameters in Length- Weight relationship were estimated 2.84 and 0.0000212 respectively and showed that E.affinis has allometric growth. The growth parameters of L∞, K and t0 were computed 90.9 (cm), 0.78 (1/year) and -0.15 year respectively. The fork length attained at the end of 1, 2 and 3 year to be 53.8, 73.9 and 83.1 cm respectively. Growth performance index caculated 8.77 which was in agreement with the finding of the other studies. Total mortality, natural mortality and fishing mortality were estimated 2.49, 0.85 and 1.64 (1/year) respectively. The Fopt and Flimit as biological reference point were calculated 0.43 and 0.56 (1/year) respectively. The exploitation ratio was estimated 0.66. The results showed overfishing on E.affinis stocks in Hormozgan Province and it is necessary to reduce activity for fishing management.

Monitoring of the fish biomass is one of the basic principal of fisheries management, but ornamental and reef fish stocks, because of difficulty of estimating their abundance, have been less studied than others. The aim of this study was to estimate the standing biomass of ornamental and reef fishes in Larak Island, in the Strait of Hormuz.

Standing biomass of the fish species was assessed seasonally using Underwater Visual Census Method (UVCm) in coral reefs and  mesophotic coral reefs in Larak Island throughout 2018 and 2019. Two popular methods in UVCm (belt transect and stationary point) were used based on topography of sea bottom. The confidence interval of estimated standing biomass is calculated using bootstrapping method.

The standing biomass of ornamental and reef fishes is estimated as 2522.18, 5222.17 and 1325.15(Kg.) in Site 1, Site 2 and Site 3, that are located in 3-15meters depth. The standing biomass at Site 4, was estimated as 884.13kg. The minimum were observed in summer, also the result showed  that the standing biomass in summer was significantly lower than other seasons (P <0.05). In addition, the temporal diagnostic test showed that population structure of fish in the spring, autumn, and winter seasons was similar but significantly different from the population structure in summer.

The less of standing biomass in summer season can be affected  by seasonal migrations of fish in tropical and subtropical waters to deeper waters, in order to trade of the stresses caused by temperature fluctuations.

Scombridae and Thunnus tonggol is one of the most commercial family species in the Persian Gulf and Oman Sea. In order to come up with the responsible fishing pattern, there was a need information about cohort and recruitment pattern data were collected simple randomly from five major artisanal fish-landing sites included, Bandar Jask, Bandar Sirik, Bandar Abbas, Bandar Kong and Bandar Parsian, from April 2015 to March 2016. Cohorts (based on Bhattacharya's method), and recruitment pattern were determined by using FiSAT II software. The fork length individuals ranged from 22 to 132 cm. There was a significant difference among  monthly averages of lengths  fish caught. The mean of individuals in period of study was 70.87 cm. Fishes were separated in 2 to 6 class during the year. Recruitment pattern were seen in all month of year but with only peak. The maximum recruitment pattern were in July then August with 16.6 and 15.62% respectively. The rercorded results showed that the responsible fishing pattern, there was a need to fishing manage  of this species.

Artificial reefs are used for increasing of aquatic biodiversity and stock rehabilitation in the word.  Fish Biodiversity was evaluated in artificial reefs that is located in Bandar –E-Salakh ((Qeshm island, concrete pipe (St1)), Bandar-E-Bostaneh ((Bandar-E- Lengeh) concrete pipe, St2) and St3 (Bandar-E-Bostaneh concrete pipe, pyramidal and Reef ball) in 20 meters. For this purpose, these selected underwater visual census method and randomized complete block design from 21Mar. 2017 to 20Mar.2018 seasonally. Measuring of biodiversity indices were obtained maximum of shanon- wiener (2.5), simpson (0.88), and margalf (8.22) indices in A.Rp,p,b, furthermore were concluded   the highest values of shanon- wiener (3.17), and margalf's richness (5.02) indices related to Heniochus acuminatus and Pomacanthus maculosus respectively . A normal log model is concluded from SHE analysis in between stations, also is resulted MacArthur’s broken stick model in species level, that is shown  more balanced distribution of resources among species of the community. In this study, was determined the role of artificial reefs in increasing of fish biodiversity and was found complexity of the physical structure for more efficiency in St3.