Author/Authors :
Mousavi-Sabet ، H نويسنده Department of Fisheries, Science and Research Branch, Islamic Azad University, Tehran, Iran.Fisheries Department, Faculty of Natural Resources, Univer , , Kamali ، A نويسنده Department of Fisheries, Science and Research Branch, Islamic Azad University, Tehran, Iran , , Soltani ، M نويسنده Department of Fish Health & Diseases, Faculty of Veterinary, University of Tehran, Iran , , Bani ، A نويسنده Fisheries Department, Faculty of Natural Resources, University of Guilan, Sowmeh Sara, Iran , , Esmaeili ، H. R نويسنده Department of Biology, College of Sciences, Shiraz University, Iran , , Khoshbavar Rostami ، H نويسنده Iranian Fisheries Research Institute, Golestan, Iran , , Vatandoust ، S نويسنده Department of Fisheries, Babol Branch, Islamic Azad University, Babol, Iran , , Moradkhani ، Z نويسنده - Department of Fisheries, Science and Research Branch, Islamic Azad University, Tehran, Iran ,
Abstract :
در تحقيق حاضر برخي جنبه هاي زيست شناختي يك چرخه كامل توليدمثلي سگ ماهي جويباري بوم زاد ايران، سگ ماهي كيوانCobitis keyvani (Mousavi-Sabet, Yerli, Vatandoust, Ozeren and Moradkhani, 2012) در رودخانه تالار، حوضه جنوبي درياي خزر، شمال ايران، با نمونه برداريهاي ماهيانه به مدت يكسال مورد بررسي قرار گرفت. هماوري، شاخص وضعيت، شاخص گنادي- بدني، شاخص اصلاح شده گنادي- بدني و شاخص دابريال مورد بررسي قرار گرفتند. آزمون رگرسيون ميان ميزان هماوري و طول كل، وزن بدن، وزن گناد و سن ماهيان ماده مورد آزمايش قرار گرفت. تفاوت معني داري بين تعداد كل ماهيان نر با تعداد ماهيان ماده در جمعيت مورد آزمايش مشاهده شد، در حالي كه تعداد ماده ها بيشتر بود. ماهيان نر و ماده به ترتيب در طول كل بيش از 45 و 49 ميلي متر و سنين 1+ و 2+ بالغ بودند. ميانگين قطر تخمكها 56/0 ميلي متر بود. اين ماهيان در رودخانه تالار از اواسط ارديبهشت تا اواخر تير ماه، زماني كه دماي آب 7/18 تا 24 درجه سانتي گراد بود، تخم ريزي كردند. ميانگين شاخص گنادي- بدني ماهيان ماده بالغ در ابتداي دوره توليدمثل 09/10 درصد و با دامنه تغييرات از 6 تا 25 درصد محاسبه گرديد. ميانگين هماوري مطلق و نسبي به ترتيب 2211 و 586 بودند. ميزان هماوري مطلق به صورت معني داري به وزن بدن و وزن گناد وابسته بود. بر اساس روند ساليانه شاخص هاي گنادي- بدني و دابريال مي توان بيان نمود كه اين ماهي داراي دوره توليدمثلي طولاني مدتي مي باشد. دوره طولاني توليدمثل و ميزان بالاي هماوري در اين ماهيان سازگاريهايي هستند كه ماهيان كوچك و كوتاه عمر، با شرايط محيط زيست خود ايجاد نموده اند.
Abstract :
Some aspects of the reproductive biology of Cobitis keyvani (Mousavi-Sabet, Yerli, Vatandoust, Ozeren and Moradkhani, 2012), an endemic Loach fish species from the Talar River in the southern Caspian Sea basin, in north of Iran was studied by regular monthly collections throughout a year. Fecundity, condition factor, gonado-somatic, modified gonado-somatic and Dobriyal indices were estimated. Regression analyses tested the dependence of fecundity on fish length, weight, gonad weight and age. Significant differences were observed between the total number of females and males, females being more abundant. The mature females and males were longer than 49 and 45 mm in total length, and +2 and +1 in age, respectively. The average egg’s diameter was 0.56 mm. The spawning of Cobitis keyvani from Talar River took place from May to late July, when the water temperature is between 18.7 to 24.0°C. At the beginning of the reproduction period, the average GSI values were 10.09%, ranging from 6 to 25% in ripe mature females. The absolute and relative fecundity were 2211 and 586 respectively. The absolute fecundity was significantly related to body weight and gonads weight. Based on the gonado-somatic and Dobriyal indices, it was concluded that the fish has a prolonged active reproductive period. Their long reproductive activity and high range of fecundity are types of adaptation by short-lived small fishes to environmental conditions.
