en Biology & physiology Biology & physiology پژوهشي Orginal research papers <font face="Times New Roman" size="3"> </font><p class="MsoNormal" style="margin: 0cm 0cm 0pt text-align: justify line-height: 115% unicode-bidi: embed direction: ltr text-autospace: text-justify: kashida text-kashida: 0% mso-layout-grid-align: none"><span style="mso-bidi-language: FA"><font size="3"><font face="Times New Roman">Some aspects of the reproductive biology of <i>Cobitis keyvani </i></font></font><a name="OLE_LINK4"></a><a name="OLE_LINK3"><span style="mso-bookmark: OLE_LINK4"><font face="Times New Roman" size="3">(Mousavi-Sabet, Yerli, Vatandoust, Ozeren and Moradkhani, 2012)</font></span></a><font face="Times New Roman" size="3">, 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.</font></span><font size="3"><font face="Times New Roman"> Fecundity,<span style="color: black"> condition factor, gonado-somatic, modified gonado-somatic and Dobriyal indices </span>were estimated. Regression analyses tested the dependence of fecundity on fish length, weight, gonad weight and age. <span style="mso-bidi-language: FA">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. </span>The spawning of <i>Cobitis keyvani </i>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 <span style="mso-bidi-language: FA">average</span> GSI values were 10.09%, ranging from 6 to 25% in ripe mature females. <span style="mso-bidi-language: FA">The absolute and relative fecundity were 2211 and 586 respectively. </span><span style="color: black">The absolute fecundity was significantly related to body weight and gonads weight</span>. <span style="mso-bidi-language: FA">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.</span></font></font></p><font face="Times New Roman" size="3"> </font> Gonado-somatic index, Dobriyal index, Spawning, Condition factor, Fecundity, Iran 383 393 http://jifro.ir/browse.php?a_code=A-10-1-164&slc_lang=en&sid=1 H. Mousavi-Sabet Mousavi-Sabet@guilan.ac.ir 10031947532846003223 10031947532846003223 Yes A. Kamali 10031947532846003224 10031947532846003224 No M. Soltani 10031947532846003225 10031947532846003225 No A. Bani 10031947532846003226 10031947532846003226 No H. R. Esmaeili 10031947532846003227 10031947532846003227 No H. Khoshbavar Rostami 10031947532846003228 10031947532846003228 No S. Vatandoust 10031947532846003229 10031947532846003229 No Z. Moradkhani 10031947532846003230 10031947532846003230 No