نوع مقاله : مقاله کامل علمی - پژوهشی
نویسندگان
1 مرکز تحقیقات و آموزش کشاورزی و منابع طبیعی استان مرکزی
2 دانشگاه علوم کشاورزی و منابع طبیعی گرگان
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
In recent years, problems with providing electricity requirements for cold-water fish farms in the dual-purpose ponds of the Markazi province, have caused widespread losses in these farms. Therefore, it seems necessary to investigate cold-water aquatic species with high resistance to oxygen reduction, temperature changes, and increasing ammonia in the water. As the narrow-clawed crayfish Astacus leptodactylus is endemic to Iran, in this study, the feasibility of cultivating this species as a resistant and low-demand aquatic animal was investigated in this province. To determine the actual conditions, this study was conducted in the environment of several dual-purpose agricultural farms with earthen and concrete ponds in the two cities of Mahallat and Khomein. A total of 11,500 crayfish weighing 25 grams and averaging 10 centimeters in length, caught from Aras Dam, were prepared and stored at a density of 20 pieces per square meter in 3 concrete ponds with a total area of 300 square meters and at a density of 5 pieces per square meter in 3 earthen ponds with a total area of 1,100 square meters, and were kept for 72 days from the beginning of the summer season to the end of this season. 10 crayfish samples were randomly taken every week from both types of ponds and were biometric. The growth rate of crayfish in earthen ponds was estimated to be 0.32 grams per day and in concrete ponds to be 0.15 grams per day. In examining the length-weight relationships, negative isometric growth was obtained for both types of ponds. The mean final length, weight, and condition factor in earthen ponds were significantly higher than in concrete ponds (P<0.01). Due to the pH of less than 7 in concrete ponds, the survival rate in this type of ponds was very low and was estimated to be 10%, while the survival rate in earthen ponds was 65%. In conclusion, it should be noted that the most important problem in the cultivation of narrow-clawed crayfish is the lack of a domestic market and the instability of its price and export status. It was also concluded that the best way to exploit the Astacus leptodactylus species is to produce in natural water resources and protect its reserves, and that the cultivation of this species in agricultural water storage ponds in Markazi Province is not acceptable compared to the trout species that are currently cultivated.
کلیدواژهها [English]
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