رضا عباسپور نادری

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 process of catching fishing gear that goes out of control is called ghost fishing. Abandoned, lost or discarded fishing gears (ALDFG) can cause adverse economic and environmental effects. Passive fishing gears, such as cages, produce more severe effects after being released into the water. Gargoors are one of the types of cages, which every year a large number of them are left in the sea in the Persian Gulf and the Oman Sea, for various reasons. In recent years, a new generation of gargoors with a rebar body covered with net are used in the waters of Bushehr. In this study, which was conducted from November to July 1400 in the waters of Bushehr, totally, in 310 cruises in 30 coordinates, by 9 vessels, 90 gargoors made of rebar were surveyed. All of them were baited with wolf herring and catfish. 24 species from 12 families were identified. The most observed species was Orange-spotted grouper (Epinephelus coioides). The results showed that all the gargoors made of rebar, if they are not lost, return to the land after the end of fishing. The main reasons for getting lost were theft, trawling, and bottom gillnets, respectively. Also, to confirm the sampling results, 40 questionnaires were distributed among the fishermen. According to the results, rebar gargoors are preferred over wire gargoors in terms of life, strength, economic efficiency and lower amount of ALDFG. It is recommended that researchers combine their knowledge with the experiences of fishermen to design gargoors with fewer disadvantages while maintaining the merits of different gargoor models, especially from the economic and environmental point of view.

In the fishing season of 2018, fishing information, atmospheric and marine information were collected for investigating the effect of environmental factors on the amount of catch per unit effort (CPUE) of banana shrimp (Penaeus merguiensis) and Sartiz (Metapanaeus affinis) in Bandar Abbas, Qeshm and Bandar Kolahi by Means of ranking tests, permutation test and regression calculations.According to the result obtained during 49 trawl operations, the total weight of shrimp was 1932 kg, including 1379 kg of Banana shrimp with an average of 12.56 (with a 95% confidence interval of 9.68 to 15.45) kg/hour and Jinga shrimp with an average of 5.18 (with about 95% confidence was recorded (3.69 to 6.68) kg/h. The RDA ranking chart showed that the CPUE of Banana shrimp had a direct and significant relationship with the factors including depth, rainfall, and sea surface temperature. In addition, it had a slight relationship with wind speed, cloudiness, humidity, salinity, and wave height. Instead, Jinga shrimp CPUE was directly related to salinity and sea surface temperature and was inversely related to wave height and humidity. Based on the permutation test results, these relationships were not significant. The effect of environmental factors on Banana shrimp CPUE by regression calculations showed that the variables of floating speed and salinity (P<0.01) and humidity and cloudiness (P<0.05) were significant in the negative binomial regression model. The pseudo-Poisson model indicated the variables of sea surface temperature (P<0.05) and salinity (P<0.1) had a significant effect on the CPUE of Jinga shrimp. The present study shows the extent and manner of influence (direct or inverse) of environmental factors on the amount of successful shrimp fishing.

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..

Regarding to the role of law awareness in social discipline, awareness of fisheries rules and regulations will be crucial in advancing fisheries affairs. Research with study personnel awareness central headquarter central fisheries organization of Iran of the fisheries rules could measure level of awareness and their teachings in adhere direction implementation of under sector laws. 

With use of questionnaire, was collected personnel information about law provisions and executive regulations rule on the protection and utilization of the Islamic Republic of Iran aquatic resources and also their corrective opinions were collected and the scoring method was used in statistical analysis. 

 The results showed an average score of 13.8 and a score of 72.7% of the total score at a rate of 33/5% were aware of the rules and regulations of fisheries. Despite 53.8% of the generalities awareness of the rules, awareness of the more specialized rules of fishing and aquaculture was less than expectation. They were about 95% and %77 of the votes that the rules and regulations of the fisheries believed did not need to be reviewed and revised and they did believe to there was a conflict among the tasks of fisheries and other organizations, respectively. Managerial problems, planning, policy making and structural were identified as one of the most important problems in the fisheries sector. 

So despite a little awareness about of the rules, in addition to the need for review and elimination of contradictions and legal interactions the training of the rules should be more serious until sovereignty and rules enforcing can create more sustainable activities in the field of fisheries.

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.