en Stock assessment Stock assessment پژوهشي Orginal research papers <font face="Times New Roman" size="3"> </font><font size="3"><font face="Times New Roman"> </font><p class="MsoNormal" style="margin: 0cm 0cm 0pt text-align: justify line-height: 120% unicode-bidi: embed direction: ltr"><span style="mso-bidi-language: FA"><font size="3"><font face="Times New Roman">This paper aimed to investigate the fishery and biological characteristics of anchovy Kilka in Iranian waters of the Caspian Sea from 2005-2007, including length and age structure ,<span style="color: black">Von Bertalanffy</span> growth parameters, length and age at first capture,<span dir="rtl"></span><span dir="rtl"></span><span dir="rtl"><span dir="rtl"></span><span dir="rtl"></span> </span>condition factor, sex ratio, natural and fishing mortality.<span style="color: black"> The examination of catch data approved that Kilka population in the Caspian Sea have been declined a few years ago following entrance jellyfish Ctenophora M<i>nemiopsis leidyi</i>. The greatest destruction of anchovy kilka catch was occurred while the catch of anchovy from 4250 tonnes in 2005 reached to 924 tonnes in 2007</span></font></font><a name="OLE_LINK5"></a><a name="OLE_LINK4"><span style="mso-bookmark: OLE_LINK5"><font face="Times New Roman"><font size="3">. The results showed that <i>K</i> value and L</font>_{<font size="2">∞</font>}<font size="3"> calculated 0.375/year, 131.7mm, respectively. The instantaneous coefficient of natural mortality was estimated 0.49/year.The instantaneous coefficient of fishing mortality</font></font></span></a></span><font face="Times New Roman"><font size="3"><span style="mso-bookmark: OLE_LINK4"><span style="mso-bookmark: OLE_LINK5"> and total</span></span><span style="mso-bookmark: OLE_LINK4"><span style="mso-bookmark: OLE_LINK5"><span style="mso-bidi-language: FA"> mortality</span> was </span></span><span style="mso-bookmark: OLE_LINK4"><span style="mso-bookmark: OLE_LINK5"><span style="mso-bidi-language: FA">0.51 /year and 1/year, respectively. The Exploitation rate was calculated as 0.51</span>.</span></span><span style="mso-bookmark: OLE_LINK4"><span style="mso-bookmark: OLE_LINK5"><span style="mso-bidi-language: FA"> The length and age ranges restricted comparison to last decade and sharply decreased recruitment. <span style="color: black">In the past few years, </span></span><span style="color: black">the main reasons of <a name="OLE_LINK1">disintegrates </a>among anchovy Kilka stocks in the Caspian Sea were</span></span></span></font><span style="mso-bookmark: OLE_LINK4"><span style="mso-bookmark: OLE_LINK5"><font size="3"><span style="color: black mso-bidi-language: FA"> synchronized overfishing competitive anchovy Kilka with <i>M. leidyi</i></span><span style="color: black">.</span></font><font size="3"> </font></span></span></font></p><font face="Times New Roman"> </font></font> Caspian Sea, Clupeonella engrauliformis, Age, Growth, Sex ratio, Overfishing 796 806 http://jifro.ir/browse.php?a_code=A-10-1-200&slc_lang=en&sid=1 A. A. Janbaz aliasgharjanbaz@yahoo.com 10031947532846004739 10031947532846004739 Yes H. Fazli 10031947532846004740 10031947532846004740 No R. Pourgholam 10031947532846004741 10031947532846004741 No F. Kaymaram 10031947532846004742 10031947532846004742 No M. A. Afraei Bandpei 10031947532846004743 10031947532846004743 No S. Abdolmaleki 10031947532846004744 10031947532846004744 No K. Khedmati 10031947532846004745 10031947532846004745 No