جستجوی مقالات مرتبط با کلیدواژه « خلیج فارس و دریای عمان » در نشریات گروه « شیلات »

Given the importance of Pampus argenteus (Euphrasen, 1788), and the overfishing pressure, this study aimed to determine some population parameters of this species (mortality and growth parameter) in the Persian Gulf and Oman Sea. Sampling was carried out using trawl, gillnet, and Moshta during 12 months from April 2018 until March 2019. In this study, 955 biometric samples were weighed. An information-theoretic, multi-model inference (MMI) approach was taken to analyzing grow and best model was selected using Akaike’s information criteria (AIC). Chen & Watanabe Method was used to estimate the natural mortality. Mean length and weight values (mean ± standard error) for males were 16.68±0.22 cm and 202.71±7.75 gr, respectively and for females were 20.57±0.34 cm and 350.12±15.95 gr, respectively. Results showed that the Gompertz was the best model for male and female. The logistic model can be used to explain growth of males (considering to Akaike difference was less than two). The value of asymptotic length, k and L0 in Gompertz Model were estimated 29.53 cm, 0.527 year-1 and 4.1 cm for males, respectively and 36.2cm, 0.448 year-1 and 4.1 cm for females, respectively. Natural mortality, fishing mortality and total mortality and E was calculated 0.7, 0.81, 1.51 and 0.54, respectively. Results of this study shows that this specie is under overfishing pressure and need to better management policies in this area including time, place and fishing gear limitation for catching. Also overfishing can be reduced with building Marine Protected Area.

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 present research project has been implemented with the aim of introducing aquatic research axes based on the pillars of food security. For this purpose, the stakeholders, strengths and weaknesses, threats and opportunities of the sub-sector of fisheries and aquatics were investigated and the basic research axes were determined based on the elements of food availability, access to food, food consumption and health, and the stability and sustainability of food. Also, in addition to determining the research axes, the research priority of different groups and species of aquatic animals was determined based on the scoring index (0-10). The results showed that the beneficiaries of the fisheries sector have a wide range and the main ones who will directly benefit from the research results are aquaculture farmers, fishermen, processors and exporters of aquatic products. From the point of view of strengths, weaknesses and opportunities and threats, the existence of valuable genetic resources, fisheries knowledge and the country's policies for the development of fisheries and aquatics are among the strengths, and natural factors such as pollution of water resources, reduction of marine resources and climate change are among the most important threats. are counted From the point of view of the main axes of research in the pillar of food availability, fishing, stock assessment, aquaculture, health and aquatic diseases, in the pillar of access to food, supply markets, economic and social issues and the final price of the product, in the pillar of food consumption, quality and consumption culture, in the pillar of food sustainability, sustainable exploitation of aquatic life, reduction of waste, and increase in productivity were identified as priorities. In terms of species priority based on fertility, cold-water fish breeding, production management in shrimp, cold-water and warm-water fish, product health and transformation industries were given the highest points. In Caspian Sea aquatics, the most research points were given to health, nutritional value, storage, maintenance and market, and important Persian Gulf and Oman Sea aquatics received the most points for health and exploitation management.

Chl a is the main pigment of phytoplankton, which is an indicator of phytoplankton biomass and reflects the primary production in the marine environment. In this study, level 3 (4 km) data of Chl a concentration of Persian Gulf and Oman Sea for the period of 2003- 2018 were used. The data was converted to raster format in ArcGIS10.5 environment and then the numerical values of each pixel were extracted in R (version 4.0.2). Missing data were observed in Chl a data, to solve this problem, DINEOF algorithm was applied and non-parametric Mann-Kendall and Sen’s Stimulator tests were used to analyze Chl a concentration trends. The results showed that the maximum concentration of Chl a is in September (0.09 to 18.75 mg / m3) and October (0.23 to 18.03 mg / m3) and the minimum concentration of Chl a in May (0.22 to 5.74 mg / m3) and June (0.20 to 5.12 mg / m3). The trend of Chl a concentration variability over the study period was negative in most areas and not significant. These analyses provide an overall description of Chl a concentration variability in the Persian Gulf and Oman Sea based on satellite observations; however, further investigations based on in situ observations are needed to achieve better understanding of the patterns of of Chl a concentration alterations.

The DINEOF algorithm is a parameter free technique based on iterative EOF analysis that is used to calculate the missing data in a given satellite data set (without requiring any prior information). In this study, the DINEOF technique has been used to fill the gaps in chlorophyll-a data series in the Persian Gulf and Oman Sea. Level 3 data (4 km spatial resolution) of chlorophyll-a concentration obtained from MODIS sensor (2003- 2020) for the study area were used. In some of the images several gaps were found in different months of the year. Images with gap in the Persian Gulf and Oman Sea were reconstructed by rtsa.gapfill R-package and DINEOF algorithm in R software. The linear regression analysis was performed between the missing and reconstructed data, and also parameters such as RMSE, MSE, MAD and SNR were calculated to evaluate the validity and performance of the DINEOF algorithm. The maximum number of the gaps in data series were found in July. Hence, the images of July have been examined and reconstructed as the case study. The original maps of chlorophyll-a concentration showed that the maximum number of the gaps were in July 2009 and 2015. Evaluation of the results showed a high accuracy of DINEOF-reconstruction method (e.g. in July 2014, R2 = 0.83, RSME = 0.34, MAD = 0.14, MSE = 0.10). The results showed that the implementation of the DINEOF algorithm (in R) to reconstruct the gaps in chlorophyll-a concentration images could serve as a rapid and efficient technique.

This study aimed to investigate Growth modelling of the milk shark (Rhizoprionondon acutus Ruppel, 1837) from October 2019 until march 2021 for 18 months in northern waters of the Persian Gulf and the Oman Sea (Hormozgan Province). Overall, 317 shark samples of R. acutus including 137 males and 180 females were weighted. Results of the present work indicated that length-frequency distribution of both sexes were statistically different. Exponential relationship between total length and total weight of males and females were as W=0.0021L3.1508 and W=0.003L3.062 , respectively. After optimization by a non-linear regression through least square method, this relationship was obtained for males and females as W=0.0028L3.078 and W=0.0025L3.106, respectively. Males were estimated for the oldest age at 8 years with the length of 91.15 cm while females were estimated for the oldest age and tallest length at 10 years and 95.5 cm, respectively. By adoption of multi-modelling approach, the best model fittedd to indicate how to grow for the females of milk shark was Gampertz Growth Model (AIC=48.14, ∆AIC = 0). Logistic model had also a considerable protection to draw the growth of females according to AIC (AIC=50.02, ∆AIC= 1.87).  The best model fitted to show how to grow the males of milk shark was Logistic Model (AIC=36.33, ∆AIC= 0). Gampertz model had also a moderate protection to draw the growth of males (AIC=42.46, ∆AIC= 6.12), but three parameterized Von Bertalanfy model showed no efficneby to draw the gorowth of males (AIC= 53.2, ∆AIC= 16.86). . This study was performed for the first time on growth and mortality parameters of the milk shark in Iranian waters of the Persian Gulf and Oman Sea. Regarding the legal and illegal fishing pressure of this valuable species, this is recommended to apply the presented results for wider future studies as a basic study and to monitor its stock status with more precision annually, so as the managers can use these results to adopt scientific-management approaches for the protection of this precious species from extinction.

The present study was carried out to determine and compare proximate composition and minerals (K, Na, Ca and P) in the edible tissue of Sillaginid species, including Sillago arabica, Sillago chondropus, Sillago indica and Sillago sihama in the southern waters of Iran. The fish species were collected from two stations in Persian Gulf (Bushehr and Hormuz Island) and one station in the Oman Sea (Chabahar) during a period from December to March 2020. Moisture, fats, ash and protein content were determined using AOAC standard method and the amount of minerals was measured using ICP-MS. The average moisture content was (70.3 ± 1.9 to 79.7 ± 1.3%), protein was (14.1 ± 2.1 to 21.9 ± 1.3%), fat was (1.5 ± 0.3to 3.9 ± 0.1%) and ash was (3.4 ± 0.8 to 4.5 ± 0.9%). The highest amount of elements was obtained for phosphorus (1060.4 ± 180.3-1693.2 ± 162.3) and then potassium (597.5 ± 82.3-1153.1 ± 137.6). This study showed that all four species of Sillaginid species in our country's waters are rich in protein with a protein content of more than 15%. All the fish analyzed for fat were lean with fat contents less than 0.5%. The Na/K ratio values, which was calculated less than 1 in all four species. The results of this study confirmed Sillaginid species as a valuable nutritional source with suitable protein and minerals content.

Scomberomorus guttatus (Bloch and Schneider, 1801) is one of the most important commercial fish of the Scombridae in the southern waters of Iran, which plays an important role in the human diet. The catch of this species has increased in recent years, and due to the limited data available on its stock in southern waters, it is not possible to use models based on complementary data to assess its stock. In the present study, the catch-maximum sustainable yield (CMSY) and the Bayesian surplus production (BSM) models were used to determine the sustainable exploitation and fisheries reference points of Scomberomorus guttatus caught in the southern waters. Data related to the last 23 years from 1997 to 2019 were collected and entered into the model to calculate fisheries reference points. According to the results, it seems that the BSM model applies the estimates with less sensitivity. The calculated value for B/BMSY by the CMSY model was estimated to be more than 1.0 and the value of F/FMSY was less than 1.0, which indicates the healthy stock status of this species in the southern waters of Iran. By applying the forecasting model, the increasing trend of fishing was predicted in 2033. If this trend continues, the value of B/BMSY will fall below 1.0 and the value of F/FMSY will increase to about 1.99. If the catch is not reduced from 2028, the stock will start to decrease in the years after 2030 and will be overfished. Based on the obtained fisheries reference points, the maximum sustainable yield (MSY) was estimated as 9,000 tons, and this amount was predicted to be 15,000 tons in 2033. In general, the estimated fisheries reference points in this study can be an effective aid in understanding the status of Scomberomorus guttatus stock in the southern waters of Iran and reveal the effects of the application of management policies on its stocks, which can ultimately develop compatible management plans for proper exploitation of its stocks in the region.

In this study, the morphometric and meristic characteristics of Psettodes erumei in two regions of Bandar Abbas and Bandar Jask were investigated. Up to30 Psettodes erumei fish were prepared from each region and after performing bioassay operations, 29 morphometric characteristics and 9 meristic characteristics were measured and counted. According to the results, the average coefficients of variation in the morphometric characteristics of right-handed and left-handed fish in Bandar Abbas region are 0.34 and 0.41, respectively, and the average coefficient of variation of meristic factors of right-handed and left-handed fish is 0.14 and 0.17. The mean coefficients of variation of morphometric factors of right-handed and left-handed fish of Bandar Jask are 0.25 and 0.24, respectively, and the mean coefficient of variation of meristic factors of right-handed and left-handed fish is 0.10 and 0.10. Also, Psettodes erumei fish had a significant difference in 25 morphometric factors and 1 meristic factor between these regions (P <0.05). The height of the anterior fin, the height of the dorsal fin, the height of the ventral fin on the dark and light surface, the length of the base of the thoracic fin on the dark and light surface and the width of the mouth are the most important morphometric factors. There was no significant difference between the parameters measured in Psettodes erumei fish in any similar area (P> 0.05). According to these results, the differences between the morphometric and meristic characteristics are more pronounced, which is itself due to different environmental conditions in these two regions.

The Persian Gulf has a different environment for corals compared to other parts of the world. 17 coral islands and some coastal areas in the northern part of the Persian Gulf as well as Chabahar Bay in the Oman Sea are the most important coral regions of Iran. The inaccessibility of coral islands and the dispersion of research have led to inaccurate information on the number of coral reef species identified. In this research, by field study of some coral regions such as Shidvar, Farsi, Kharg, Khargo, Hindurabi and Nayband, as well as collecting studies conducted by other researchers in other coral regions, thorough information about the diversity of coral species identified in the Persian Gulf have been presented. According to studies, the number of species of coral reefs identified in the Persian Gulf waters is 96 species, which by calculating 6 species of coral reefs that are reported only from Chabahar Bay, brings the number of species identified in Iranian waters to 102 species. The identified species are from 13 families and 40 genera, among which, Merulinidae and Acroporidae each with 29 and 23 species, respectively, have the highest diversity in terms of number of species. After these two families, Poritidae with 11 species has more diversity than other families. Among the studied islands, Larak Island has the highest number of species.

In the present study, time series data of catches of Ribbonfish (Trichiurus leuptrus), in the Persian Gulf and Oman Sea from 1973 to 2018 were used and the fishing trend and average relative increase rate of catches of this species for this period estimated. Using fishing trend (linear regression equation) and average relative increase rate in catches of Ribbonfish over 21-year period, the amount of harvest for the next 5 years (2019-2023) for the whole Persian Gulf and Sea of Oman and for each province, were predicted. Finally, the harvests of 32000 t, which ensure sustainable exploitation of Ribbonfish and sustainability of jobs created by this fishery in the Persian Gulf and Sea of Oman, proposed and recommended to Iranian fisheries authority for implementation.

Primary production is a key indicator in the evalution of aquatic ecosystems that can directly affect carbon sequestration. Due to climate change and environmental dynamics, this component has changed spatially and temporally in different ecosystems. Therefore, to understand and monitor these changes, the most important influential parameters include; sea surface temperature, chlorophyll-a and algal bloom on this component and their changes were analyzed based on the time series. Images related to Chl-a, SST and NPP from January 2003 to December 2018 were used by MODIS sensor and VGPM model to estimate NPP in the study area. Aftar pre-processing and extracting the time series algorithm, the trend of variation was determined using the mann-kendall and theil-sen procedure. Then, using enhancing false color composite, algal blooms in the Persian Gulf and the sea of Oman were identified and the amount of chl-a concentration in the algal bloom area and outside the area was determined.  The results of trend analysis with theil-sen procedure showed that the rate of change for chl-a is decreasing in all regions except the fifth region. The highest amount was observed in the fifth region (-0.19), which corresponded to the rate of NPP. The results also show that the highest amount of NPP in the first region in March and the lowest in June and July (540 and 690 gC/m2/day), which corresponds to the amount of chl-a concentration. Despite the apparent correlation, there is no cause-and-effect relationship between SST and chl-a as well as chl-a and NPP. In this way, factors other than chl-a can be considered for algal bloom and NPP.

The rate of overfishing of Black pomfret (Parastromateus niger) in the southern waters (1997-2018) was performed based on CMSY model, R software, Bayesian status approach (Problem solving based on basic information) and Monte Carlo simulation. The average catch of this species was 5570 tons with a 95% confidence interval of 4145 to 6994 tons and the average catch increased significantly during the last two decades in the Southern Waters  (R = 0.86, P <0.05). The catch of this species in the southern waters has increased from about 2500 tons in 1997 to about 12500 tons in 2018 and Sistan and Baluchestan province has the highest trend of Black pomfret fish catch in the Persian Gulf and Oman Sea. Considering the rate of overfishing (total weight) of Black pomfret fish in the southern waters, the catch status of this species has changed from low (green color) in 2008 to medium catch (yellow color) in 2018. The overfishing rate of this species in Bushehr province is red color. It seems, in order to maintain sustainable yield, fishing effort rate and catch rate in the southern waters, especially in Khuzestan and Bushehr provinces, should be reduced.

Malabar trevally is one of the species of Carangidae family in the Persian Gulf and Oman Sea, which biological and population characteristics of this species were less been studied . In this regard, reproductive indices such as gonadosomatic, first maturity length, sex ratio, spawning season, absolute and relative fecundity were investigated. Reproduction studies of Malabar trevally (Carangoides malabaricus) were carried out in the waters of Hormozgan province from December 2016 to November 2017. Samples were collected monthly using trawl nets. Total, fork length and weight were measured. In this study, the total samples were 438, out of which 258 were females, 150 males and 30 immature. The minimum and maximum average fish fork length during the different months was 14-34 and 26.42±3.33 cm, respectively. The maturity female fork length (LM50) was 180 mm.  The sex ratio of female to male was 1.72 to 1 which showed a significant difference (P<0.05). Maximum absolute fecundity was 185432±8127 eggs in April and maximum relative fecundity of 570 23 eggs per gram in April. The minimum absolute fecundity was 66542±14197 in September and the minimum relative fecundity of 130 14 eggs per gram in June. The maximum GSI index of female and male fish were calculated 1.8 and 0.68 in March respectively which spawning could be started from April.

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.

This study aimed to a comparison of morphometric characteristics of otolith in Epinephelus coioides (88 specimens), Epinephelus latifasciatus (71 specimens), Epinephelus bleekeri (69 specimens) and Epinephelus diacanthus (145 specimens) in coral reefs of the Persian Gulf and Oman Sea. Species were collected during 2014 - 2015. All fish were identified and their otoliths were extracted to verify them. Investigation of otolith morphometric characteristics (length, breadth, weight, perimeter and, area) was conducted. Data indicate a high correlation between otolith length and otolith weight, fork length, and otolith length and between fish length and weight (R2>0.854), the highest correlation was observed in E. diacanthus (R2= 0.894). Also, the results indicate that in the studied species, biometric differences are observed along with the difference in the shape of the otolith, according to the results, the highest length, the highest weight, the highest area and the highest perimeter of otolith were related to the E. diacanthus with mean total length of 26± 3.2 cm and the average weight of 1357.27 ± 104.27 g, and the highest otolith width was related to the E. coioides with an average total length of 38 ± 1.8 cm and the mean weight of 1289.54 ± 124.42 g. This study indicated that the relationships between sagitta and morphometric characteristics of various species are different and can be used as an indicator in species identification.