سید یوسف پیغمبری

The study aimed to compare the catch composition, CPUE, and CPUA of dominant commercial fishes caught by bottom trawl nets (Plan approved by the Fisheries Organization) in different depth layers of The Gulf of Oman,Sistan and Baluchistan Province. This study was carried out during 2 sampling stages in September and March 2018 (fishing seasons). Fishing operations were carried out periodically in layers of 50 meters, 50 to 100 meters, and above 100 meters by the Avash industrial trawler equipped with a bottom trawl net with a power of 2250 horsepower in 24 designated stations (4 times of net hauling per day in 6 days). Based on the calculated CPUE and CPUA results in the first stage, a significant difference was observed between the CPUE and CPUA amounts of John's snapper in the first and second depth layers, and between the CPUE and CPUA amounts of Cobia in the first and third depth layers (P<0.05). Javelin grunter (CPUE: 99.9±45 and CPUA: 2122.6±1132.2) in the first depth layer, black pomfret (CPUE: 53.6±28.7 and CPUA: 738.2±407) in the second deep layer, and longrakered trevally (CPUE: 89.9±40.2 and CPUA: 1181.6±515.7) in the third deep layer had the highest amount of CPUE and CPUA. In the second fishing stage, there was a significant difference between the amount of CPUE and CPUA of the Javelin grunter, Talang queenfish, and Cobia in the second and third depth layers (P<0.05). Javelin grunter (CPUE: 71.2±21.1 and CPUA: 1230.9±428.6) in the second depth layer and longrakered trevally (CPUE: 44.5±9.9 and CPUA: 596.2±129.3) in the third depth layer had the highest amount of CPUE and CPUA. Based on the obtained results, the highest amount of CPUE and CPUA were estimated in the first, third, and second depth layers in the first sampling stage, and in the second and third depth layers in the second sampling stage, respectively.

Cephalopods have short life and global distribution except freshwater that these make them importance for study of their dynamics population. So, the purpose of this study was to estimate the biomass of cephalopods (Amphioctopus marginatus, Uroteuthis (Photololigo) edulis, Uroteuthis (Photololigo) duvaucelii, Sepia saya, Sepia prashadi, Sepia omani, Sepia stellifera and Sepia pharaonis) with the catch dynamics model (generalized depletion model) in the NE Gulf of Oman at the end of the fishing season (of bottom trawlers) in the summer and autumn of 2020. The catch data of these valuable fisheries species were obtained through field sampling from commercial fishing in the depths of 74-212 meters by an industrial bottom trawler for 17 consecutive days in the "Gowater-Pasabandar-Beris" fishing grounds (at least 12 nautical miles from the shoreline according to the new move-on rule). The highest total abundance and biomass belonged to Sepia pharaonis by 23431 individuals and 27005.78 kg. Also, the lowest total abundance and biomass belonged to Uroteuthis (Photololigo) edulis by 8 individuals and Sepia saya by 0.397 kg, respectively. The abundance response for most of the stocks was a hyperdepletion (β > 1), while the fishing effort response for most of them was an effort synergy (α > 1). Also, most of the selected models were executed in the presence (open population) of perturbations (pulses). Cuttlefishes had the highest and octopuses had the lowest biomass, respectively. Probably, this study was the first survey of biomass for mentioned species in the waters of the Islamic Republic of Iran - except Uroteuthis(Photololigo)duvaucelii and Sepia pharaonis. The advantages of implementing catch dynamics model based on commercial fisheries activities are practical, operational, and close-to-reality estimates, lack of some costs of scientific surveys, also lack of additional pressure on aquatic resources (especially in nursery grounds) due to the implementation of fisheries activities (fishing operations) within the permitted limits (spatial-temporal).

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.

In this study, the catch composition and the catch per unit effort (CPUE) of sturgeon spawners caught by the gill net were investigated in the fishing grounds of Mazandaran province in two regions 3 and. Sampling and data collection of sturgeon spawning fish was done seasonally from 7 fishing grounds using gill nets with a mesh size of 150 mm. The results of the Chi-square test showed that there was a significant relationship between the time and place of Caught Persian sturgeon and Starry sturgeon (P<0.05) There was a significant relationship between the time and place of fishing with the abundance of fish spawners caught between regions 3 and 5 with spring and autumn seasons (P<0.05). There was a significant relationship between the time and place of fishing with the abundance of Starry sturgeon spawners caught between regions 3 and 5 only in the winter season (P<0.05). Also, a significant difference was observed between the amount of catch per unit effort of the spawning fishes caught in regions 3 and 5 (P<0.05) and between the averages of the catch per unit effort of the spawning fishes caught in the spring and summer seasons. Also, there was a significant difference between autumn and winter (P<0.05). Since the spawners of the caught sturgeon belonging to the Starry sturgeon and Persian sturgeon had the highest number compared to other species, so the results show the influence of the spatio-temporal factors of the habitats on their spawners.

There is limited information about the relationship between abiotic and biotic variables of the shrimp/prawn stocks in the Persian Gulf. Consequently, the effect of some environmental factors, including temperature, salinity, and depth, on the abundance of two commercial species, Jinga shrimp (Metapenaeus affinis) and green tiger prawn (Penaeus semisulcatus), on the coasts of Khuzestan Province were assessed in the present study. For this purpose, regression, and RDA, as an ordination method, were employed to investigate the impacts of the depth, temperature, and salinity on the capture per unit effort (CPUE). The maximum CPUE for M. affinis in the western region (Life’h- Buseyf) was 18.75kg/h at a depth of 5m, 28.5°C and 40ppt salinity. It was obtained the 2.03kg P. semisulcatus per hour from the eastern region (Bahrkan) at 22m, 32°C, and 40ppt. The results of RDA revealed that the changes in CPUE have a statistical relationship with environmental variables. So that this relationship is direct for Penaeus semisulcatus and inverse for Metapenaeus affinis, and the sea depth was the most significant factor in fishing both shrimp/prawn species. The selection of the leading variables has also confirmed these results. Additionally, the temperature was recognized as the subsequent influencing factor, and the salinity variable had no significant effect on the CPUE of species. Regression models showed only a significant impact of depth on the CPUE of Penaeus semisulcatus, and the capture of Metapenaeus affinis lacked any statistical effectiveness of environmental variables.

This study aimed to investigate the changes and growth pattern of Beluga sturgeon fishing in fishing regions of Golestan and biological characteristics of this species over a period of 13 years. The highest amount of Beluga sturgeon fishing was in 2008, when a total of 95 pieces of this species were caught from five fishing grounds in Golestan province, and the lowest amount was caught in 2020, when 3 pieces of this species were caught. The results showed that the highest average total length was observed in 2020 and the highest total weight was observed in 2017 and the lowest average total length and total weight was obtained in 2011.The sex ratio of male to female elephant fish in the thirteen-year period was 0.66:1, which was significantly higher than the female population (X2=19.69, p<0.05). The range of growth coefficient (b) for the population of Beluga sturgeon between 2008 to 2020 years varied from 2.56 to 3.97. The results of Pauli test for the relationship between length and weight of Beluga sturgeon species showed that the growth pattern of this species in 2008 and 2010 were negative allometric, in 1393, 1396 and 1397 positive allometric and in 2009, 2011, 2012, 2013, 2015, 2016, 2019 and 2020 were isometric. In general, in a period of 13 years, the amount of elephant fishing in the coasts of Golestan province decreased by more than 90%, so in this region, this trend for Beluga sturgeon is among the most endangered species, concluding an alarm for conservation of this valuable species in Caspian Sea..

This study estimated the discarded catch of the Moshta gear and the length at maturity parameter (Lm50) of two species of discard aquatics Arius maculatus and Plicofollis dussumieri. Sampling carried out in the city of Bandar Abbas since December 2014 for one year. After specifying the maturity of samples by the Biswas (1993) method, to calculate the length at maturity the least-squares technique under the king (2007) method was performed in Data Analysis Solver of Excel 2013. Discard catch included 65.23% of the weight and 74.93% of the number while commercial catch included 34.77% of the weight and 25.07% of the number. According to the results, the length at maturity of Arius maculatus was 28.2 cm, 51.50% were below puberty. The length at maturity of Plicofollis dussumieri was 32 cm, 62.3% were below puberty. The results of this study showed that Moshta with a high diversity of trapped aquatics, while some of these aquatics are caught immature, was a threat to fisheries stocks in Hormozgan province and the Iranian waters of the Persian Gulf.

The present study estimated relative frequency index of Purpleback flying squid and Oman cuttlefish also evaluated the effect of depth, distance, and time of capture (before & after noon) on them. Sampling was in the west of the Gulf of Oman at the spring of 2019. The depth of the Gulf was 208 to 285 meters. The vessel used was an industrial Myctophid trawler and the sampling gear was a rope trawl that operated with the fishing technique in a water column (the bottom panel was maximum 6 meters higher than the bottom of the Gulf). According to field observations, the average catch per unit of effort index in Purpleback flying squid and Oman cuttlefish was estimated to be 7584.22 and 1345.066 gram / hour based on weight and 19.062 and 18.250 number / hour based on number, respectively. Based on the selected models, the variables of depth and distance had a significant effect on catch per unit of effort for Purpleback flying squid (P<0.05). With increasing depth and distance, the catch per unit of effort for squid increased. However, based on the results, no significant effect of the studied variables on the relative abundance index of Oman cuttlefish was observed, given the lack of sufficient research on this theme and the discard caught of these species in Iranian waters, more extensive research to manage their stock in the Gulf of Oman is a need..

This study aimed to investigate the changes and growth pattern of Persian sturgeon fishing in fishing regions of Golestan and biological characteristics of this species over a period of 10 years. The highest amount of Persian sturgeon fishing was in 2012, when a total of 143 pieces of this species were caught from five fishing grounds in Golestan province, and the lowest amount was caught in 1398, when 49 pieces of this species were caught. in the present study, the maximum total length of Qarabrun was in 1397 with a total length of 257 cm. Mianqaleh fishing farm had the highest number of catches (471 pieces) of this species and the lowest amount of catches (26 pieces) for this species was recorded in Chalasht fishing farm. The results showed that the highest average total length was observed in 2014 and the highest total weight was observed in 2017 and the lowest average total length and total weight was obtained in 2012. The sex ratio of males to females of Persian sturgeon species in the ten-year period was 1.24: 1, where the male population was higher (p < 0.05). The range of growth coefficient (b) for the population of Persian sturgeon in the years 2011 to 2020 varied between 2.60 to 3.82, The results of Pauli test for the relationship between length and weight of Persian sturgeon species showed that the growth pattern of this species in 2011 and 2012 was negative allometric, in 2015 positive allometric and in 2013, 2014,  2016, 2017, 2018, 2019 and 2020 It was isometric. Conclusion of this study shows that in a period of 10 years for Qarahbrun species had a decrease of 75%, so in the waters of Golestan province this trend for Qarahbrun is among the most endangered species and this means an alarm for this valuable species It has been heard in the Caspian Sea.

The purpose of this study was to evaluate the number, catch composition, and catch per unit effort (CPUE) of sturgeon spawners by gillnet in the fishing grounds of Golestan province. Sampling and data collection were conducted in the 4 fishing grounds according to the fishing seasons of sturgeon fish using gillnets (Polyamide) with a mesh size of 150 mm from autumn 2018 to autumn 2019. Five species of sturgeon fish including Acipenser persicus, Huso huso, Acipenser gueldenstaedtii, Acipenser nudiventris, and Acipenser stellatus were caught during the sampling period. The highest fish weight was observed in autumn 2019 (946 kg) and the lowest was in spring 2019 (242 kg). The highest total catch weight and fishing effort were obtained for matured males of A. persicus (389 kg and 0.9 g/fishing effort) and the lowest was for matured females of A. stellatus (13 kg and 0.03 g/fishing effort). According to the results of the Chi-square test, the separate and simultaneous effect of sampling time and the location was significant on the number of matured Acipenser persicus (P<0.05).

The diameter of the ring connected to the balustrade Conical Lift Net was initially 1.5 m. But gradually the diameter of the attached ring increased Today it is about 4 meters. The seems to increase the diameter of the ring This increased the number of non-target fish in this method. The purpose of this study was length frequency and species composition of non-target fish caught in Conical Lift NetMay 1997 in two fishing ports of Babolsar and Amirabad by four fishing vessels during 33 torrents at a depth of 40-50 m. After identifying the species caught, the total length and weight of the specimens were measured. From a the total of 193 fish caught, the highest and lowest percentage of total relative frequency fish species Alosa caspia were (37.8%)and Gasterosteus aculeatu (4.7%). Relative frequency of other species caught in Babolsar and Amirabad ports Syngnathus abaster were 38.8% and 28%, Gasterosteus aculeatu 50% and 0%, Mugilidae 11.11 and 18.2%, Alosa caspia 0% and 41.7%, respectively. Rutilus frisii kutum was 0% and 12%. The results also show that the frequency of fish caught in Amirabad fishing port is higher than Babolsar fishing port and strongly dependent on area (p < 0.01). The results indicate the high pressure resulting from the production of Bycatch fishing on non-commercial species in Amirabad fishing port. Most frequency in Babolsar and Amirabad fishery ports were respectively in the length class of 4.5-5.5 cm Gasterosteus aculeatu and length class of 15.5-5.5 cm Syngnathus abaster in fish.

The bony fish of the Caspian Sea are among the most important and most valuable fish in this sea, which unfortunately their reserves have been declining for many reasons in recent years. In this research, environmental factors were investigated on catching important bones such as white rutilus kutum (Kamensky, 1901), golden multitude of Chelon auratus (Risso, 1810) and Alosa saposchnikowii (Grimm, 1887). The catches were carried out by blade cooperatives on the Miankale Peninsula in Golestan Province during 73 times during the 1965-93 fishing season. In this research, 8914 whitefish, 4067 golden babies and 2335 piglets were biometric and weighed. The results showed that for goldfish with relevant data in model 5, it can be 50% for whitefish with the relevant data in model 3 can be 47% and for fish only one model with The very low coefficient of determination with a meaningful parameter yields quantities of catch per unit of effort. The results also showed that the effect of environmental parameters and spring on the average fish frequency per unit of effort was observed that the temperature factor, especially the increase of maximum temperature, was the most effect on the frequency of whitefish in the Caspian Sea, while increasing the humidity and precipitation on fish catch; Reducing the winds of the year will have the highest impact on the catching of wild boar and word. The highest catch per unit of effort was observed at 31 and 33 mm fountain.

Yellowfin Tuna (Thunnus albacares) is one of the most important commercial and neritic fish species which has known because of ecological importance and wide distribution around the world. The aim of this study was to determine relative index of abundance for Yellowfin Tuna from 2007 to 2016, also we evaluated effect of some explanatory variables (year, month, vessel tonnage and net height) of catch per unit effort data in traditional gillnet fishery standardized by general linear model (GLM) in the Oman Sea. Standardized catch per unit effort is an important entrance in stock assessment as an annual abundance index. The results of this study have shown that all explanatory variables influence CPUE significantly in GLM model with lognormal error distribution; CPUE of Yellowfin Tuna increased 0.007 and0.0016 by raising one ton of vesselchr('39') tonnage and one meter of net height, respectively. Relative index of abundance of Yellowfin Tuna has the lowest quantity in 2011, remain stable till 2013 then increase to highest level in 2016, which is shown the catch rate can increase by raising catch effort. There is a seasonal trend in standard CPUE of Yellowfin Tuna with the highest catch rate in cold season. Monthly relative index of abundance has shown highest catch rate occurred in February and March.

This study was conducted to survey of distribution and abundance of cutlassfish (Trichiurus lepturus, Linnaeus 1758) as target species between the fishing grounds of Bushehr and Hormozgan provinces. Sampling operations were carried out during the summer season in Bushehr province and autumn season in Hormozgan province in 2013. The fishing operation was done using commercial trawler vessel with a length of 27 m, the width of 7.2 m during 73 times net hauling in the fishing seasons. The used net in this research was a mid-water trawl net with a polyethylene yarn and mesh size of 75 mm (stretched) in the codend. The highest length frequency of cutlassfish was observed in the length range of 84-92 cm and the least length frequency was in the length range of 28-36 cm. The biomass and mean CPUA in Bushehr were 17169.55 tons and 8624.42 ± 1076.58 (kg nm-2) and in Hormozgan were 7425.804 tons and 8105.74 ± 1529.87 (kg nm-2), respectively. Also based on depicted maps by GIS software and CPUA index, Most densities of trapped cutlassfish in Hormozgan fishing grounds were around Hengam and Greater Tomb islands, and in Bushehr (Motaf area), there was a horizontal distribution in the western waters of this province.

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.

Longtail Tuna (Thunnus tonggol) is one of the most important Commercial and Neritic fish species which are widely distributed throughout neritic tropical and temperate waters of Indo-Pacific. The aim of this study was to determine relative index of abundance of Longtail Tuna from 2007 to 2016, also we evaluated effect of some explanatory variables (Year, Month, Vessel tonnage and net height) of catch per unit effort data in traditional gillnet fishery standardized by general linear model (GLM) in the Oman Sea. Standardized catch per unit effort is an important entrance in stock assessment as an annual abundance index. The results of this study have shown that year and month as explanatory variables influence CPUE significantly in GLM model with lognormal error distribution, but the increasingly effect of vessel tonnage and net height were not significant. Relative index of abundance of Longtail Tuna has shown increasing trend from 2007 to 2016 with the highest pick in 2013, that is shown catch rate can increase by raising catch effort. There is a seasonal trend in standard CPUE of Longtail Tuna with the highest catch rate in warm season. Monthly relative index of abundance has shown highest catch rate occurred in May and June.

This research was carried out within two years (2016-2018) in Bushehr province due to limited information about the fishing and navigation equipment of the traditional fishing fleet. For this purpose, 10% of gillnet and trawl vessels were selected randomly as a sample and then technical characteristics of fishing tools were investigated. Also, their navigation and safety equipment were considered. The results showed that trawl and gillnets are not in compliance with standard regulations. The investigated trawl nets showed that their mesh sizes were smaller than defined sizes for these nets. The results showed that vessels are in moderate condition in terms of navigation and safety equipment. According to the obtained results, development, and implementation of comprehensive regulations of standard fishery tools in the traditional fishery community is necessary.

The purpose of this study was to investigate the effects of depth and soak time of Gargoors on catch per unit of effort (CPUE) for Pharaoh Cuttlefish (Sepia pharaonis (Ehrenberg, 1831)). The sampling time was February-March 2017, which was coincided with the cuttlefish fishing season operated by the Gargoor fishing vessels of Bushehr port. Randomly a total of 20 Gargoor fishing vessels were sampled. The Jackknife resampling method was used to obtain more reliable estimates. Also, the Generalized Linear Model (GLM) was used to determine the relationship between depths and soak time (explanatory variable) with catch per unit of effort (response variable). According to Jackknife resampling (similar to the results of the field observation), for 2–8 days soak times than 8–14 days soak times (545.720> 509.759) and 25–40 m depths than 10–25 m depths (536.940> 516.494) the average catch per unit of effort for Pharaoh Cuttlefish was higher. Besides, based on the above resampling, the catch per unit of effort confidence intervals for soak times of 2–8 days and 8–14 days also the depths of 10–25 m and 25–40 m were 382.671-708.768, 386.225-633.293, 347.822-685.126, and 410.345-693.535, respectively. On the other hand, the results of the generalized linear model showed that both depth and soak time of Gargoors had a significant effect on the catch per unit of effort (p<0.1); such a way that, increasing the depth and decreasing the soak time increase catch per unit of effort. However, based on field data, it is expected that if Gargoor fishing vessels with operating at depths of 25-40 meters and submerging their Gargoors within 2–8 days, they could be able to perform better CPUE for Pharaoh Cuttlefish according to the fishing effort used.

The purpose of Present study was the effect of resizing of Mesh Size on lenght frequency and weight averages, frequency Kilka Fish Catch in Conical Lift Net May 1997 in Babolsar fishing port by four fishing vessels during 33 torrents at a depth of 50-40 m. After identifying the species caught, the total length and weight of the specimens were measured The results showed that in all 4 nets the highest percentage of fishing frequency was from 11.5 to 12.5 cm length range. length range 7.5 - 6.5 in 7 and 9 Mesh Size; . length range 8.5 - 7.5 in 9 Mesh Size; . length range 15.5 - 14.5 in . the length range Mesh Size 7 and 16.5 - 15.5 . the length range in Mesh Size Items 7, 8 and 9 were not observed . the length frequency distribution of common Kilka Catch by funnel net was similar to 4 different Mesh Sizes. there was no significant difference between the average length of common kilka Catch with different Mesh Sizes. And the highest frequency in 8mm Mesh Size with an average frequency of 954. the results showed a correlation between the Mesh size and the total length. No significant correlation was found between the Mesh size and total length of common Kilka. Indicates that the Mesh size of the fountain does not determine the total length.

This study was conducted to determine density and distribution of commercial fishes (Argyrops spinifer- Carangoindes talamparoides and Saurdia tumbil)  by swept area method in Persian Gulf waters (Busher province). Sampling operation (27 hauls) was done by a trawler (Tabas class) with long 26 m and width 7.4 m in fishing season. Midwater trawl ned had a 72 m head rope and mesh sizes were 400 mm and 80 mm (stretched) in square and codend respectively. The averages of  CPUA  and biomass for Saurdia tumbil - Carangoindes talamparoides and Argyrops spinifer were estimated 218.21 ± 27.71 (kg/km2) and 8851.15 tons, 159.19 ± 22.11 (kg/km2) and 6457.02 tons, 171.75 ± 30.78 (kg/km2) and 6966.68 tons respectively. The results showed that the best depth of fishing effort for Argyrops spinifer and Saurdia tumbil was 30 m but for Carangoindes talamparoides was 20–30 m. The biomass of mentioned species in Motaf area represents the potential for commercial fishing in the spring. The results of this study indicated the water depth changes affected harvesting of two species Saurdia tumbil and Argyrops spinifer and had no significant impact on the species Carangoindes talamparoides.

The purpose of this study was an estimation of the exploitation and also determination of some biological aspects for trapped Pharaoh Cuttlefish by wire pot (Gargoor) in Bushehr province (north of Persian Gulf). The data collection process was carried out from February 22 to April 19, 2017. The landing and yield of caught Pharaoh Cuttlefish by wire pots in Bushehr province, for 12 years, were 354.833 tones and 162.260 kg. km-2. year-1, respectively. The length (mantle length) and weight range of caught Pharaoh Cuttlefish (300 biometeried specimens) were 13-36 (24.62 ± 4.59) cm and 300-4200 (1870 ± 791.61) gr, respectively. Randomization Test and Two Independent Samples Kolmogorov-Smirnov Test were used for comparing the length frequencies, while showed a significant difference in all different parameters of catch; such as soak depth of Gargoors, soak time of Gargoors and types of vessel (p=0.001). The average of condition factor for Pharaoh Cuttlefishes was 1.25 which indicates the favorable living conditions of trapped Pharaoh Cuttlefish by Gargoor. Independent Samples T Test was used for comparing the condition factors, while just showed a significant difference in soak time of Gargoors (p=0.001). The results showed that due to the overlapping and synchronization of the fishing and reproduction season of Pharaoh Cuttlefish in Bushehr province and based on the range of length and weight frequencies of trapped Pharaoh Cuttlefish by wire pots, it can be stated that fishing operation using wire pots is a selective method for Cuttlefish.

Beach seine is fishing gears that occupy all depths of water from surface to bed by non-gillnet net. Increasing non-standard catches caused this survive was done to standardization of the beach seine mesh size. The research was started from winter of 2017 to spring of 2017, performing 73 hauling with four mesh sizes of 26, 28, 30 and 33 mm (knot to knot) in the bag area of ​​the beach seine in Miankaleh region of Golestan Province. According to the mesh size used in the bag section, the results showed that the highest amount of catches from different mesh size was done in size of 26 mm. Also, the maximum lengths were found for Liza aurata, Risso, 1810 in different mesh size in the 30-35 cm class length and for Alosa caspia, Linck, 1790 for 35-40 cm and for Rutilus kutum, Kamensky, 1901 at 30 to 35 cm. Also, in the mesh size of 26 mm, 50 percent of Lisa fish was caught at the length of 24.87 centimeters, in mesh size of 30 mm, 25.66 centimeters and mesh size of 32 mm, 26.65 centimeters. Also, the length of 50% of the permitted catch was obtained 25.5 centimeters by using 30 mm mesh size. According to the results, it was found that the Beach seines in the region did not caught selective and did catch much fish below the standard length.

The aim of this study was to investigate catch composition and catch per unit effort of invertebrates in shrimp trawl in different areas and depths. This research was carried out in Hormozgan coastal waters (Bandar Abbas and Hormuz Island) at depths of less than 10 meters, 10-20 meters and over 20 meters in shrimp fishing season in 2015. 40 hauls that duration of each one was approximately 2 to 2.5 hours with a total catch of 7623 kg were done. The catch composition included 1068 kg of commercial shrimp and 6555 kg of by-catch that included invertebrates and fish which were 2386.8 and 4168.2 kg, respectively. The results showed that the catch composition consisted of 14% shrimp (1068 kg), 31% by-catch invertebrates (6555 kg) and 55% by-catch fish (4168.2 kg). There were significant differences among the CPUE in the different areas and depths as well as the interaction of area and depth on CPUE of the total catch, target species (Shrimp), Oratosquilla oratoria, Portunus pelagicus, Crustacea (Small crab), Sepia pharaonis, Anthozoa, Demospongiae, Rhizostomatidae (Jelly fish), Asteroidea and Octopoda (POratosquilla oratoria, Rhizostomatidae and Sepia pharaonis and the Demospongiae was at the least.

Association between environmental variables and target species is the most important point in aquatic ecology. This study considered the possible relationship of spatial, temporal and some satellite derived environmental variables on skipjack tuna (Katsuwonus pelamis) distribution to finally help implementing of ecosystem based fisheries management for stock recovery program and management of skipjack tuna. Results of generalized additive model (GAM) (by assuming two distributions; binomial and Gaussian) revealed temporal and spatial explanatory variables plus net primary production (NPP), sea surface temperature (SST), sea surface salinity (SSS), mixed layer depth (MLD) and ocean current indices have greatest impact on skipjack tuna distribution in both cold and warm season. Comparing of two different model showed, binomial distribution had higher ability in final model deviance explanation and its value in warm season was higher than cold season. In addition, habitat suitability study showed suitability of some parameters in cold and warm season were different, then it must be noticed in future studies. Since the first step in implementing ecosystem based fisheries management is the sufficient knowledge on ecosystem and distribution of target species in relationship to environmental variables, therefore this study could help Iranian purse seiners to improve their catch efficiency in order to help to implementing of ecosystem based management for skipjack tuna and future fisheries management in the Indian Ocean and Oman Sea.

This study conduct to evaluate the survey and assessment of beach seine fish predation by statistical analysis of fish cooperative and Golestan fisheries office data since 2006-2008. In two Miankaleh and Gomishan in the second half of the 20 October second decade every year till the end of April the following year for a period of 6 months through pre-coastal continues by cooperatives Fishing blades and supervision of experts blade to the fishing and fishermen are employed Results, showed significant difference in amount of osteochities fish density and species in three years of study and was decreased (p<0.05).Also, the osteochities fish density was Cyprinus.carpio> Rutilus.firisi kuttum> Rutilus.rutilus in two first years of survey. Followed the decreasing Carp predation In 2008 than two past years Kuttum predation was increasing than past brightly and predation density was kuttum> Sea carp> Roachin 2008. So, kuttum by 503525 kg had the upper level of predation in2008 and Roach by864 kg had the lower level in 2007.