【摘 要】
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Reproductive biology of yeliowfin tuna in the west-central Indian Ocean was conducted from January to June 2003,December 2003 to June 2004 and September to
【机 构】
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College of Marine and Technology,Shanghai Fisheries University,Shanghai,200090
【出 处】
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2007全国博士生学术论坛——海洋、水产领域
论文部分内容阅读
Reproductive biology of yeliowfin tuna in the west-central Indian Ocean was conducted from January to June 2003,December 2003 to June 2004 and September to December 2005 which collected the data from surface longline by Chinese Tuna Scientific Observers.The total number of reproductive samples was 1,023 samples,including 417 ovary and 606 testis samples.Spawning season of female and male of yeilowfm found in January to June.Average monthly sex ratio was 0.59.The observed minimum length at sexual maturity to be around 101 cm for female yeliowfin tuna and 110 cm for male,respectively.Length at 50% sexual maturity was estimated at 113.77 cm for female and 120.20 cm for male respectively,whereas maturation rate was 0.066 cm-1 for female and 0.091 cm-1 for male respectively.Sex ratio by length class indicated when size of yellowfin tuna was longer the proportion of male was more than female,especially yellowfm tuna was larger than 145 cm,and all specimens were males at 160 cm and lager.Statistically,yellowfin tuna had a significant reproductive seasonality.
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