نشریه بهره برداری و پرورش آبزیان
سال سوم شماره 4 (زمستان 1393)

Chlorpyrifos is one of the organophosphate pesticides that are commonly used to control insects in domestic activities and many agricultural farms that are located in close to water sources. Hence, the present study, investigate the lethal toxicity of this pesticide. In this study, fish were treated in groups of 21 with different concentrations of chlorpyrifos (Aria brand with active ingredient 40/8% EC) for 96 hours and mortality was recorded. Toxicity tests were determined by Probit statistical analysis in software SPSS, version 16. At the end of 24 hours, mortality was 100% in fish with a concentration of 200 mg/l chlorpyrifos. LC50-96h this pesticide was calculated 83.2 mg/l. However, mortality was observed 100% for diazinon and deltametrin at the end of 96 hours. LC50-96h diazinon and deltametrin were less than chlorpyrifos that shows diazinon and deltametrin have more toxicity in comparing with chlorpyrifos. Finally, Carassius auratus is a suitable model of Cyprinidae that constitute a big group of rearing fish and because of chlorpyrifos lower toxicity, seems to using of this pesticide stead other common pesticide had been low danger in agricultural fields.

The basic purpose of the fulfillment this research has been the appointment of economical evaluation indexes of aqua-agriculture reservoirs in Golestan Province. The method of information gathering in this research has been in way survey and in method census from 42 of aqua-agriculture reservoirs that information necessary to complete questionnaire has prepared. Result showed the highest and lowest cost per hectare was Kordkuy and Gorgan reservoirs, respectively. The highest cost gradients per kg fish were juvenile preparation, rent, and labor salary. The mean net benefit was in Golestan Province 28034000 R. and Gonbad had the highest benefit/ha with 32368200 R. Aquaculture is benefit employ economically, and important for employ creating especially in rural and coastal regions.

In present study, the kinetic parameters of purified trypsin from pyloric caeca of common kilka (C.cultriventris caspia) were measured using the amidolytic (BAPNA) and esterolytic (TAME) substrates. The results of the kinetic comparison between BAPNA and TAME substrates showed that kinetic parameters including maximum velocity (Vmax), catalytic constant (kcat) and catalytic efficiency (kcat/Km) were in TAME higher than those from BAPNA while Michaelis-Menten constant (Km) showed the lower value in TAME than that from BAPNA. The Vmax value of TAME was significantly higher than that from BAPNA (p0.05). The kcat and kcat /Km values of TAME were also significantly higher than those from BAPNA (P < 0.05). The findings reveals that purified trypsin from common Kilka pyloric caeca has a higher affinity for TAME than dose that from BAPNA and so TAME can be used as substrate for trypsin activity assessment.

Because of being much perishable product as well as having low per capita consumption, much study on shrimp and its different supplying methods such as canned shrimp is needed to improve per capita consumption of seafood especially in case of shrimp. In this study, the effect of different pre-cooking methods on quality of canned Penaeus semisulcatus was studied. Although frying and baking methods had lower level (p

In recent years the use of rotifers as live food for rearing fish larvae and crustacean is very important. In this study, the effect of two concentrations (2.5×106, and 5×106 cell/ml-1) of two algae (powdered chlorella and nannochloropsis), on body and egg size of marine rotifer, Brachionus plicatilis were investigated. Rotifers were cultured in standard conditions in 500 ml plastic containers. The initial density of rotifers in different treatments was 30 ind/ml. The sampling of rotifers were conducted in the exponential phase of population growth. Based on the results, no significant difference was observed in the in the size of rotifers fed at low concentration (2.5×106 cell/ml-1) of two algae (p>0.05). But rotifer body size was high at those fed low concentrations of powdered Chlorella in compare to the high concentration. Egg size in group fed powdered chlorella was more than another group. Significant differences was observed in egg size of two groups that fed on high and low density of both algae (p

The aim of this study was determination of abundance and biodiversity of zooplankton community at integrated fish culture of grower and fingerling fishes at East of Golestan Province, Gonbade Kavous city. Sampling was done monthly at 6 ponds during one season culture from June to November 2011. During six month study period, 4 groups and 27 genuses were identified. Between recorded groups, 12 genuses belong to Protozoa, 8 genuses belong to Rotatoria, 4 genuses belong to Copepoda and 3 genuses belong to Cladocera. There is significant differences between average total density of zooplanktons at different months (P

Biological monitoring using benthic organisms is one of the best and the most inexpensive methods for anthropogenic activities evaluation in aquatic ecosystems. The purpose of Present investigation was biological monitoring of Shahrud river that was performed in the Qazvin province using by macro benthic invertebrates population. In the present investigation macro benthic invertebrate samples were collected by Surber sampler at 8 sampling stations with 3 replicates in each station for a period of one year. The collected samples were preserved in 4% formalin solution and transported to the laboratory for identification and counting. About 11636 individuals of benthic organisms were identified consist of 32 genera from 31 families, 9 orders, 5 classes and 4 phylum. The most important of Benthic organisms were included Trichoptera (42.27%), Diptera (23.77%), Ephemeroptera (16.64%) and Pelecoptera (11.74%) according to abundance. From upstream to downstream population- biological indices values and abundances of sensitive organisms decreased in the other hand abundances of resistant organisms increased. The lowest and highest values of BMWP/ASPT were 7.06 and 3.51 for station 4 and 8 respectively. Evaluation of indicators revealed less water quality at stations 2 and 8 that received agricultural, industrial and residential sewages respectively. Based on BMWP/ASPT annual average value (5.51) shahrud water quality classified on low polluted level.

The monitoring of the Management of vannamei shrimp Farms in the Gomishan shrimp Site in the best way and to its development. The objectives of the project were the calculation of growth indices, Food Conversion Ratio.The Final production of vannamei, benefit-cost or gross benefit of each Farm.This study carried out in in 1391(2012).Data collection done through questionaries personally from Farm executive managers during culture period with the arrangment of shrimp department of the Golestan fisheries organization. Results indicated that, the average production of Khazar-Abzi Farm Semi-intensive system was 1389.3 kg/ha; The average weight(gr), FCR and Survival Rate(%) were 15.3, 0.87 and 92.5 respectively. The cost of Farming and the benefit of each kilograms of shrimp produced without the calculation of the depreciation of capital assets and construactions were 34525 and 55475 Rials respectively. The average production of Farm number 13(Persian kian pad) with intensive system was 3903 kg/ha. The average weight(gr), F.C.R and Survival Ratio(%) were 14.6, 1.25 and 74.3 respectively. The Farming cost and the benefit of each kg cultured shrimp were 50402and 39598 Rials respectively.