نشریه ماهیان دریایی
سال چهارم شماره 1 (پیاپی 4، بهار و تابستان 1399)

Three new and scarce fish species including of two bony fish species, Parapercis nebulosa, Dactyloptena orientalis and eel-like species, Xiphasia setifer were identified from Bushehr waters during August and September, 2017. The species From these species, X. setifer has been reported from Bahrain, Iraq and Iran waters as under pressure species. P. nebulosa is not observed in identification keys of southern Persian Gulf, but FAO key referenced this species in the Persian Gulf area. Although the source area has not been identified, but according to the of southern countries reports, it can be indicated that this fish is only found on the northern part of the Persian Gulf. D. orientalis was reported one of the rare species in the Persian Gulf region.The results of recent studies have shown poor biodiversity in the Iranian waters of the Persian Gulf. In this regard, the status of scarce species should be classified to special concern and warrants the continued protection. Local fisheries collaborations in identifying and presenting rare and endangered species can be effective in protecting and surviving of the species.

The role of artificial reefs has been evaluated in the rehabilitation of fish by assessing the results of artificial reefs projects on commercial and ornamental fishes in Hormozgan province. The results indicate that artificial reefs have an important impact on the accumulation of fish, especially commercial fish. It was concluded the lowest amount of ornamental and commercial fish in summer in all reports, also artificial reefs of Bandr-E-Bostaneh (combination of concrete pipe, pyramidal and Reef ball structures ) showed that the complexity of the physical structure of the habitats have a positive effect on the increasing of fish. According to the findings of this research, artificial reefs can be selected as a tool for rehabilitation of aquatic resources and coastal habitats with numerous fishery and environmental benefits with correct management. It is suggested should be considered complexity of the physical structure in the design of artificial reefs for fish increasing.Also, since the basis for sustainable development of fisheries is cultural development, provision is made for the possibility of promoting the use of artificial reefs in the rehabilitation of fish stocks in the form of training programs, brochures and films in the ports and fishing cooperatives in the Hormozgan province.

The presence of nitrogen compounds such as ammonia and nitrite, in excess of the limit, can cause acute toxicity in aquatic animals and affect aquatic ecosystems and organisms. On the other hand, the entry of these chemicals into the body of fish can produce free radicals that are effective factors in the incidence of various diseases. The most important free radicals are reactive oxygen species that are considered as free radicals and are produced by various metabolic pathways such as aerobic metabolism in the mitochondrial respiratory chain. Antioxidants are protective agents against the damage caused by free radicals and can easily withstand free radicals and end their chain reaction before any degradation of vital molecules. The imbalance between the production of free radicals and antioxidant defense leads to stress called oxidative stress. In fact, oxidative stress disturbs the balance of oxidants and antioxidants in favor of oxidants, which causes the oxidation of biological molecules such as proteins, nucleic acids, lipids, and carbohydrates and leading to cellular damage. In this paper, the effects of ammonia and nitrite as oxidative agents have been discussed on the antioxidant system such as glutathione, superoxide dismutase, catalase, total antioxidant capacity and malondialdehyde in different fish.

Due to the importance of the issue and the role of O. ruber in the economics of the local fishing community, a comparative analysis of the efficiency of gillnets used was needed. The size of gillnet meshes studied included 57 mm (1.4 inches), 64 mm (1.2 inches), 83 mm (1.3 inches), 89 mm (3.5 inches) and 95 mm (3.4 inches) of monofilament and multi-filament yarns, depending on the type of net, that were compared by length frequency data collected at sample landing sites during routine visits. With an increasing in the meshes sizes, the mean length (total length) of O. ruber also increased, in which the smallest mean length (25.41 cm) was observed for mesh size of 57 mm and the largest (39.7 cm) for the gillnets with mesh size of 95 mm. The percentage frequency of fish smaller than the minimum legal size (41 cm) was fluctuated between 57.0% for mesh size of 95 mm to 96.2% for the 57 mm one, indicating the inappropriateness of the existing gillnets. Catch of fish with minimum legal size was higher in monofilament netting yarns compared to the multifilament one. In order to ensure the sustainability of catching Tigertooth croaker, the implementation of the ban on the use of all existing gillnets is imperative. Suggestion of optimum mesh size can be provided if field experiments are made by comapring some knids of mesh sizes according to the selectivity models.

The Persian Gulf and the Oman Sea contain a variety of aquatic species. Among which, Tuna fishes are very important and Kawakawa (E, affinis), one of the tuna fish that has increased its catch in recent years. In this research, trend catch and demographic characteristics and demographic characteristics of Kawakawa were estimated by collecting information from 4 catchment areas on the coast of Hormozgan province including Kang, Salakh, Parsian and Jask. In this study, more than 10,000 fish at the research stations were biometric and the growth parameters were infinite length of L∞ = 82 cm, growth factor K = 0.33 (yr-1), natural mortality M= 0.67(yr-1), mortality and mortality (yr-1), F = 0.89, total mortality (yr-1), Z = 1.56 and exploitation coefficient (yr-1), E = 0.57, and the time zero was -0.3 for the years. Relative production per recruitment, relative biomass per recruitment, exploitation rate and average annual standing stock for kawakawa species were estimated Y '/ Rp =0.04, B' / Rp = 0.21, U= 0.53 and b= 17071 (T), respectively. This study shows that the annual harvest of Kawakawa fish has reached its maximum and any increase in fishing effort will affect the kawakawa fish stock and will reduce the amount of exploitation in the long run.

In order to create species diversity in the aquaculture industry in the country, Iranian Fisheries Science Research Institute has taken special activates in introducing grey mullet in the first operation in 1984, it imported 20,000 pieces of juvenile fish from Hong Kong. Of the 20,000 imported juveniles in 1984, 10,000 to 12,000 juveniles were died, and after 5 years, only 800 breeders were raised by cultured juveniles but in 1984, as a result of snow and severe cold, all brood stock were lost. then, approximately 2,000 juvenile fish were imported from Egypt in 2009. At the same time, grey mullet was identified and caught in the Chabahar region, off the coast of the Gulf of Oman. The results showed that the highest possibility of catching broodstock in November and December and the highest presence and possibility of collecting juvenile in estuaries and coastal watersheds were determined in May and June. Providing healthy and native breeders and juveniles is very important in planning to introduce this species to the aquaculture industry. Therefore, in this review article, the results have obtained in Offshore Fisheries Research Center _Chabahar to introduction of native grey mullet of the Gulf of Oman and the possibility of catching, domesticating and transferring it to other parts of the country for culture and breeding will be briefly discussed.