عنوان مقاله [English]
Brown trout is a vulnerable subspecies of the Caspian trout fish which usually exists in the upstreams of the Caspian Sea basin Rivers, Lighvan-Chai (East Azaarbaijan) and Karaj reservoir. The fish has a good stock in Lar reservoir of Mazandaran province and 17862 license items were issued for catching the fish in summer 2006. The aim of this study was to determine the morphometric, meristic and descriptive characteristics of the fish in Lar reservoir and 190 specimens have been caught by electroshocker in Elarm, Ab-Sefid, Kamardasht and Delichai Rivers in autmn 2008 and summer and autumn 2009 and they were measured. The average weight and fork length of the studied specimens (n=190) was 136.86±103.4 g and 212.81±49.6 mm respectively. The results showed that there were 108-134 scales on lateral line, 2-5 unbranched and 8-11 branched rays in dorsal fin, respectively, 2-5 unbranched and 6-9 branched rays in anal fin, respectively and 15-21 gill rakers in first gill arch and 57-60 vertebrae, among 17 meristic count in brown trout. Among 31 measurement factors, the measured averages were as follow: head length 22.34±1.4, depth of head 14.80±1.1, maximum depth of body 20.87±1.7, base length of dorsal fin 12.52±1.2, pectoral fin length 15.60±1.2, ventral fin length 12.39±1.0, base length of anal fin 9.38±0.9, pre-dorsal distance 41.24±1.9 and pre-ventral distance 46.84±2.3% of fork length. There were no significant differences in meristic counts between male and female but there were observed 18 differnces in morphometric factors between two sexes, so that there was difference in 9 factors in α=0.001 level, 5 factors in α=0.01 level and 4 factors in α=0.05 level. In conclusion, it can be said that the results of the current morphomeristic data have many differences with investigations carried out in the Republic of Azarbaijan and certainly stock of Lar reservoir is a distinct population.
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