جستجوی مقالات مرتبط با کلیدواژه « سخت پوستان » در نشریات گروه « شیلات »

Due to the importance of export production of more than 48.8 thousand tons of farmed shrimp along with fishing about 12 thousand tons of marine shrimp, obstacles and problems of the country's farmed shrimp market were identified by completing an electronic questionnaire from 40 exporters and experts. Ranking of problems through scoring method and due to the non-parametricity of statistics, tests of chi-square and Mann-Whitney U were used in statistical analysis. Problems such as regional production and interaction, the inefficiency of the banking system for exports, the instability of appropriate supportive policies, sanctions, weak branding and the lack of an international marketing research agency The country had a lot of problems in the market. Inefficiency of the banking system in exports, sanctions and instability of appropriate protection policies among 22 market problems, ranked first to third, respectively. According to experts, the lack of knowledge of the domestic market and marketing knowledge and plan and uniformity in the production strategy was a more serious problem in the market than exporters. No significant relationship was observed between different levels of sociological characteristics of the studied groups with barriers and problems, and only the age of less than 48 years recognized more problems than those who were older. Therefore, solving the most important market problems, especially the reform of the banking system, lifting sanctions and adopting appropriate and sustainable protectionist policies should be the focus of the government.

The proliferation and cultivation of ornamental fish with an economic and decorative approach is one of the important activities of the aquaculture industry, which has grown over the recent decades and occupies a significant part of international trade. In addition to this growth and development, one of the most important challenges facing the industry is the emergence and occurrence of various diseases, including the involvement of protozoan parasites, which cause many problems in these fish, including growth retardation, delayed sexual maturation or fish infertility, casualties, high cost of treatment and control of parasites. Also, parasites often provide the basis for other diseases, such as Bacterial, Viral and Fungal infections, which cause severe mortality and morbidity. Therefore, this study reviewed the types of pathogens of ornamental fish and presented solutions for their control and treatment.

This study was carried out to comparison and survey on metazoan parasites of Otolithes ruber in coastal waters of Persian Gulf and Sea of Oman. Totally 318 fish specimens were seasonally caught by gill net, bottom trawl and hook in Khozestan, Hormozgan and Sistan and Baluchestan Provinces from summer 2013 to spring 2014. Specimens immediately were frozen and transferred to laboratory and after measuring fish weight and length, parasitological survey conducted on external and internal organs. Totally, 20 different parasites species were observed from O. ruber in mentioned areas that some of them occurred in all three regions and the others were only in one or two areas. The results of this study showed that monogeneans and digeneans had the highest occurrence in three regions while other groups were less abundant in each area. The results of statistical analyses showed significant differences among parasites abundance in different seasons. As well as a significant differences were found between male and female and parasites abundance of Digenea in Khozestan, Monogenea and Cestoda in Hormozgan and Nematoda in Sistan and Baluchesta Provinces. The prevalence of parasites depends on environmental conditions and presence of intermediate hosts that these factors are likely to be different in the three regions.

The aim of this study was estimate of diversity, density and frequency of crustacean zooplankton community of warm water fish ponds in Gonbade Kavous city at east of Golestan province. Sampling act was done during one culture period from June to November 2011. Finally 7 genuses were identify and recorded during study period. So that 4 genuses belongs to copepoda and 3 genuses belongs to cladocera. From statistical aspect, there is no significant differences between different 6 ponds observed (P>0.05). But there is significant differences between different months observed (P<0.05). So that, the highest density belongs to June and July months and lowest density belong to September and November months. The results show that the highest and lowest frequency percent of dominance genus belongs to Eucyclops sp, Cyclops sp, Daphnia sp, Diaphanosoma sp, Nauplius, Chydorus sp and Thermocyclops sp with 53, 16.5, 12, 11, 5.5, 1.5 and 0.5 % respectively. The correlation analysis between crustacean zooplankton community and water physico-chemical parameters show that total density of crustacean zooplankton community had significant correlation with NO3, PO4 and P-PO4 parameters -0.891, 0.939 and 0.968 respectively. Other water physico-chemical parameters had no correlation relative with crustacean community. The results show that crustacean of zooplankton community of fish ponds affected by ecosystem management, climate condition, water physico-chemical parameters and grower fishes.

The present study examined the effects of different levels of plant protein (soybean meal) on biochemical parameters heamolymph of freshwater crayfish (Astacus leptodactylus). For this purpose, the effects of different levels of soybean meal protein including 0%, 30%, 50%, 70%, and 100% diet on some biochemical parameters and ion heamolymph of freshwater crayfish were evaluated after 60 days of trial. Sampling of 75 samples crayfish with apparently healthy heamolymph was carried out at the end of the testing period. Based on the results, with increasing soybean meal in the diet, the amount of glucose, cholesterol, triglyceride, creatinin and total protein had a significant decrease compared to the control group. A significant difference was observed in the amount of serum enzymes activities between control group and the other treatments. The amount of Bun, calcium, and sodium were not significantly different between treatments. Also, the amount of K, Fe and P in the diets containing soybean meal had a significant decrease compared with the control group.