نشریه بوم شناسی منابع آبی
سال سوم شماره 1 (بهار و تابستان 1398)

Selection of suitable cage location is one of the most important factors for the culture of marine fish. Because this parameter represents the commercial life of aquaculture. The choice of suitable location, in addition to the effect on determining the type of cage structure (fixed, floating and submersible) and sometimes fish species, also plays an important role in the economic output. The impact of aquaculture on the environment around the cages in fish farms is effective site selection.This study was conducted with the aim of selecting an appropriate place for marine aquaculture based on the review of information sources inside and outside of Iran to determine the standard and criteria by presenting practical suggestions. The results showed that the leading countries in the fish cage culture industry, set standard and criteria for choosing the suitable location for the establishment of cages for marine fish culture. These rules are used in the context of environmental impact assessment (EIA), environmental management program (EMP) and strategic environmental assessment (SEA) in different countries. According to the above, the standard and criteria for the site selection of fish farming in marine cages in the Iran country were proposed in 28 clauses.

Due to the interference of chloride ions in saline environments, chemical oxygen demand (COD) is not possible with existing standard methods such as acid oxidation with potassium dichromate. Therefore, finding a method for COD that do not has the effect of the interfering, it can be helpful. The present research aims to provide spectrophotometric method for COD measurement. Potassium hydrogen phthalate was used to prepare COD calibration solutions according to the standard method. The solutions were prepared in distilled water and saline water. Based on the results of this study, water salinity did not affect absorption at 254 nm. In order to compare the method presented in this study, the standard method of oxidation of acid with potassium dichromate was carried out on 33 samples of wastewater. According to the findings, there is a good fit between the two methods (R2 = 0.98), therefore, it is suggested that the COD measurement equation based on absorption at 254 nm wavelength for saline and fresh environment. Because the proposed method of the present study does not used Chemicals, especially mercury and silver compounds, it can be suggested as an environmentally friendly method.

Microsatellite markers are highly effective in the field of fisheries and aquaculture, to describe genetic reserves, to select reservoirs of breeders, to identify genes encoding of important economic traits and reproductive programs as well. Investigations related to this topic were used in order to study the various populations of banana shrimp Penaus merguiensis in the three major catching areas of this species in Iran including Jask, Goatr, and Hormoz areas. functional features of Microsatellite to be used as a suitable tracker for detecting the gene flow in specific populations. Some researchers believe that the ability of the technique of using microsatellites to detect specific genetic loci for intra-population or between populatin in marine broodstocks is one of the strengths of these markers. These exclusive alleles can be considered in reproductive programs such as broodstocking, as well as hybridization, of banana shrimps ( P. merguiensis ) in the Persian Gulf and Oman Sea. This approach to using microsatellites for analyzing genetic variation in reproductive programs as well as studying the isolation and presentation of new microsatellite sites and their application as genetic markers can determine the diversity and preservation of genetic reserves of various species of aquatic organisms

Today, the shrimp industry has become one of the most popular industries in the world, as investors are keen on entering the industry. In Iran, shrimp Farming in southern and Northern provinces, especially in Hormozgan province has expanded. New areas are also to be assigned to the study, construction and utilization stages, in addition to increasing the land allocation to shrimp, shrimp density has also increased in ponds, due to the arrival of white western species and due to the proper biological characteristics it is used to farming Indian white shrimp. Due to the increasing amount of storage and production, the quality of the water in the pools will also be different from the past, but the farmers still use traditional methods of shrimp breeding, and the physicochemical properties of water and the impact of these parameters on the production of shrimp harvested attention They have nothing to do. In this paper, we will try to highlight the importance of some important parameters in shrimp pools and their effects on production

The western region of Anzali wetland (Abkenar) is located in Guilan province in Iran. This area is between the 37o 49'-37o 51' north latitude and 49o 25'-49o 27' east longitude. Abkenar wetland is importance in the region due to its special position, such as the fishing of native marginalists. Survey of regional ecological characteristics and aquatic plants distribution contributes to the water ecosystems, conservation and sustainable use of their potential. Flora of this region includes 14 plant species which belong to 11 families. The largest families are Potamogenaceae (2 species), Thyphaceae (2 species). Phragmites auastralis is the most abundant species in the western region of the Anzali Wetland. The result showed that according to the classification Raunkiaer system (Raunkiaer, 1934) there were 21/42% Therophytes, 35/71% and 42/8% Holophytes. Also, Investigation on chorology of plant species showed that 57/14 Cosmopolitan, 21/42 Plurinational, 7/14 European-Siberian-Mediterranean and 7/14% Irano_Touranian in The western region of Anzali wetland.

The purpose of this study was to investigate the strength of longline fishing yarns before and after use in fishing operations in the Persian Gulf region. 10 threads were selected from each thread of the original and the secondary rope, and transmitted to the laboratory for review. In order to ensure the uniformity of the yarns, FTIR was detected by the threads of the thread and the yarns were tested in the form of non-knot threads in dry condition to test the strength of the Instron. The results of the values of strength against rupture, for example, threading new and used in rope original order of 318.74 ± 8.84 and 295.31 ± 6.7 for examples of yarn new and used in rope sub 309.65 ± 30.83 and 301.1 ± 13.3 respectively. Results showed that the average yarn strength of the new rope Main rope subsidiary of strength yarns used rope Main rope the sub more. The mean strength against tear samples of yarn new and used in both rope and sub significant difference yarn have there (P< 0.001). The strength of the individual samples of yarn Instron showed that the yarns used in addition to reducing its strength and flexibility and softness are less likely to affect the marine environment and the effects of pressure on the ropes is. In other words, the threads worked after a while, in addition to reducing their strength, they get worse. By examining the samples,