جستجوی مقالات مرتبط با کلیدواژه « استان مازندران » در نشریات گروه « شیلات »

The aim of the study was to determine the quality of the inlet and outlet water of five selected rainbow trout breeding farms in Mazandaran Province (Haraz, Chalous, Tonekabon, and Sari) based on environmental parameters during four seasons in 2021-2022. Forty samples were collected and measured based on standard methods. According to the results, the range of water temperature (3.0-24.0°C), air temperature (2.0-25.0°C), DO (6.16-12.24 mg/l), BOD5 (0.24-2.76 mg/l), COD (2.40-93.70 mg/l), EC (284-783 µs/cm), turbidity (1.12-220-0 NTU), TSS (2-288 mg/l), pH (7.44-8.62), total phosphorus (0.2-2.12 mg/l), phosphate (0.01-0.206 mg/l), ammonium (0.012-0.538 mg/l), ammonia (0.001-0.018 mg/l), nitrite (0.001-0.426 mg/l), nitrate (0.52-6.10 mg/l), fecal coliform count (6-1000 CFU/100ml) and water quality index (WQIIR) (62.0-91.0) were registered. The water quality of this river was placed in class III (low pollution) based on the average parameters of organic pollution (BOD5 and COD) and human activities were not one of the main factors in the increase of organic matter in the river. The concentration of ammonium and nitrite was within the threshold limit, but the concentration of phosphate in all the inlet and outlet stations and in different seasons was more than the maximum limit of unpolluted rivers. The results showed that the WQIIR was in the range of 62-91. 7.5% of the total data and the mean of this index indicated the relatively good quality of the inlet and outlet water of the rainbow trout breeding farms. The highest quality of water, i.e. very good quality, is recorded in 12.5% of all data, which is observed at the inlet water of rainbow trout breeding farms. The outlet quality index of the farms was lower than its inlet, but it was categorized as good quality. The overall WQIIR (77.4±6.6) in all inlet and outlet stations indicates that the water of this farm is suitable for fish and wildlife and also suitable for rainbow trout breeding.

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.

The existence of a lower feed conversion ratio (FCR) of some imported trout species and the reduction of the feeding costs of such trout, compared to Iranian egg has made it attractive to the use of foreign input. On the other, the imported eggs are significantly more expensive and cannot be supplied permanently, because of sanctions in Iran. It can also transfer disease to the Iranian trout farms. Therefore, this import problem is a threat to food security and farms' production. Hence, the use of imported egg versus domestic ones, on the one hand, is less welcomed in Iran, due to the possibility of instability and disruption in domestic production has been a major challenge in trout farming in this country. So that, the use of imported trout eggs has been questioned. Hence, the present study sought to find a solution to this problem. For this purpose, the concept of economic efficiency in the DEA model is employed in propagation and hatchery farms of Mazandaran Province. The findings revealed that the identified farms almost made the appropriate use of their inputs; So that the average technical efficiency among them is 87%. However, allocative efficiency was the main distractive factor in the farms; Thus, the average economic efficiency of them (propagation and hatchery farms) is lower and about 43%. Also, the average economic efficiency in propagation farms with domestic eggs (41%) is more than in farms with the use of just imported eggs (38%). Therefore, Changing the production structure in total dependant farms of Mazandaran (on imported eggs) to propagate domestic eggs can be advisable. Moreover, the reduction of feed prices and the use of capital-intensive technology instead of labor-intensive technology is another solution to ensure economic efficiency and sustainable food security in this province.

Mariculture of trout fish in cage, which is a new approach of Iranian fisheries organization was followed by the last decade draining years and estimation limitation of fresh water fish production in Iran, harvested more than 2700 MT. of trout fish which is the successful choice of cage cultured fish species in three northern provinces - Caspian Sea. Final costs of fish production affected by different financial parameters such as fixed and current investments, in cage condition determined using industrial cost accounting or final production cost. In order to obtain final costs of each kg trout fish cultured in cages of Mazandaran coastal water, questionnaire from 5 trout fish cages were gathered during 2016 in that province. All data and costs are based on a cage with 15 MT capacities. Overall, initial fish biomass for releasing to the cage with the highest costs(41%) of total costs, followed by feed 37%, maintenance and 5 years amortization fixed investment (10%), Insurance(5%) and labor costs(0.018%) are the main factors final costs of the cage fish production. In this study this final production cost of one Kg fish cultured in cages system of Mazandaran province was calculated 129764 , which is 10 % lower than the price of fish cultured in raceway system(142740 Rials).

One of the most important bacterial fish diseases which have caused some outbreaks in rainbow trout farms in Iran is streptococcusis. The farmers have been suffering from huge economical losses due to the disease outbreak in different rainbow trout farms in Iran. The aim of present study was to determine the rate of streptococcusis incidence in different growth stage in the farmed rainbow trout in Haraz River in Mazandaran Province, Iran. Fish specimens along with water samples were collected from 10 haphazardly selected fish farms on a monthly basis throughout a year. After clinical observations, isolation and recognition of strep strains were undertaken using biochemical and PCR tests. The results showed that 4.6% of juvenile fish showed clinical sings of streptococcusis while only 0.7% had strep. contamination. These rates in adult specimens were 8.9 and 1 percent, respectively. The main isolated bacterial strain was Streptococcus uberis.

Fish parasites from Valasht Lake and Chalus River were studied in spring 2005 and summer 2006. Fish specimens were caught by hand net and transported to local laboratory alive. We found three protozoa species, Trichodina trutta and Ichthyophthirius multifiliis on Oncorhynchus mykiss; and Chilodonella hexastica on the skin of O. mykiss and Leuciscus cephalus. We also separated metazoan parasites from the fish in the two sampling sites that included Gyrodactylus derjavini infecting skin and gill of O. mykiss, G. sp 1 infecting Alburnoides bipunctatus, G. sp2 from Barbus capito and G. sp3 from Capoeta capoeta gracilis and Tetraonchus menonteron that infested the gills of Esox lucius. Other parasites which we found were Myxobolus saidovi from the gills of C. c. gracilis, Bothriocephalus gowkongensis from intestine of Barbus capito, Raphidascaris acus from intestine of E. lucius and finally Argulus foliaceus from skin of Chalcalburnus chalco ides. This is a first time report of a new host, B. capito for Bothriocephalus gowkongensis and a new locality Chalus River for Myxobolus saidovi parasites. Furthermore, with the exception of Tetraonchus menonteron which have been reported before, the rest of the parasites of the fishes from Valasht Lake are reported for the first time.

Diversity, distribution, catch per unit effort (CPUE) and population structure of sturgeon stocks in the Iran coastal areas of the Caspian Sea waters less than 10 meters deep was studied during 2003-2005. We also recorded total length and weight of all sturgeon specimens in five regions which was done by gillnet with mesh sizes 26, 33, 40, 60, 100, 150 mm during seasonal sampling from autumn 2003 to summer 2005 in the south of the Caspian Sea. Totally, 301 fish were sampled in 2003-2004 including Acipenser persicus (244) A. stellatus (35), A. nudiventris (13), and A. guldenstaedti (9). A total of 412 fish were sampled over the years 2004-2005 of which 369 were A. persicus, 14 were A. stellatus, 7 were A. nudiventris, 21 were A. guldenstaedti, and one was Huso huso. In 2003-2004, the CPUE for A. persicus, A. stellatus, A. nudiventris, A. guldenstaedti were 4.07, 0.58,0.22 and 0.15 respectively, whereas for A. persicus, A. stellatus, A. nudiventris, A. guldenstaedti, and for Huso huso the CPUE was 6.15, 0.23, 0.12, 0.35 and 0.02 respectively. In 2003-2004, the mean total length was 26±10.86 cm A. persicus, 49.7±14.5 cm for A. stellatus, 38±13.79 cm for A. nudiventris and 43.1±10.25 em for A. guldenstaedti. In 2004-2005, the mean total length was 21.0±18.56, 5205±25.53, 30±13.09, 23.37±12.2 and 50 cm for A. persicus, A. stellatus, A. nudiventris, A. guldenstaedti, and Huso huso respectively.

A series of studies were conducted to evaluate the possibility to culture Penaeus indicus in coastal area of Gorgan bay concerning the proper climate potential of Behshahr zone during summer till autumn 2000.
Thirty two water samples were collected from four shrimp ponds for further laboratory studies to measure some physicochemical parameters such as: temperature, pH, salinity, transparency, nitrogen, phosphorus, D.O. according to the Russian Standard (1988).
As a result, the range of water temperature, pH, salinity and trasparency were 24.5-29.0°C, 8.02-8.18, 31.5-43.5 ppt and 21-50cm, respectively and the fluctuation concentration of D.O, NH4+, NO2-, PO4-3 were 3.8-9.5 ml/l, 0.0022-0.015, 0.0021-0.1210 and 0.0145-0.3710 mg/l, respectively.
As a conclusion, this shrimp species can be easily adopted with different climate, so this region is suitable for shrimp culture as view point of temprature and salinity. For demonstration of this issue, 1he semi-intensive shrimp culture has been successful. Also the toxic material such as ammunia and nitrite did not show any restriction for shrimp culture.