We report the current status of Taimen (Hucho taimen) population in Wusuli River of China. The amount of catch per year was only 1 800 - 5 400 individuals ranging from 2-15 years old during 1998-2002. Of all the captu...We report the current status of Taimen (Hucho taimen) population in Wusuli River of China. The amount of catch per year was only 1 800 - 5 400 individuals ranging from 2-15 years old during 1998-2002. Of all the captured, individuals with sexual maturity were up to 30%-70% (female maturity at 5 years old and male 6 years old). Sex ratio varied greatly among different localities. Its breeding population mainly consisted of males aged 5-10 years and females aged 8-13 years’old, which spawned in May each year.Females breed once with about 4 000 - 23 000 eggs produced every 2-3 years. Taimen grows fast and average growth rate is about 10 cm per year prior to 10 years’s old, which corresponded with von Bertelanffy’s equation calculated as L t=246 41[1-e -0 0407(t-0 4625) ] and W t= 174 075 72 [1-e -0 0407(t-0 4622) ] 2 9537 , and the relationship between body length and weight was W=0 015018L u 2020 .展开更多
The sex ratio(♂/♀) of plateau pika′s(Ochotona curzoniae) population was studied by re-captured method in the region of the Haibei Alpine Meadow Ecosystem Research Station, Northwest Institute of Plateau Biology, th...The sex ratio(♂/♀) of plateau pika′s(Ochotona curzoniae) population was studied by re-captured method in the region of the Haibei Alpine Meadow Ecosystem Research Station, Northwest Institute of Plateau Biology, the Chinese Academy of Sciences from April of 2001 to August of 2002. The result showed that there was no significant difference from 1∶1 in adult′s sex ratio in whole breeding season,whereas the sex ratio of juvenile had some fluctuations among different age stages. The sex ratio of the second litter varied significantly from embryo to 60-day-old, but no difference at the first and the third litter. We concluded it was caused by conflict between maternal strategy and juvenile′s strategy. No significant differences of sex ratio were found both in adult and juvenile between 2001 and 2002. The sex ratio of plateau pika before and after overwintering did not vary. In summary, we proposed that sex ratio of plateau pika′s population was not influenced by exogenous factors, but some self-regulation mechanisms may be involved.展开更多
基金supported by the National Natural Science Foundation of China (Grant No. 30400047)the Training Fund of Northeast Normal University Scientific Innovation Project (Grant No. 07013)the Jilin Provincial Science and Technology Department (Grant No. 20070558 and 20090575)
文摘We report the current status of Taimen (Hucho taimen) population in Wusuli River of China. The amount of catch per year was only 1 800 - 5 400 individuals ranging from 2-15 years old during 1998-2002. Of all the captured, individuals with sexual maturity were up to 30%-70% (female maturity at 5 years old and male 6 years old). Sex ratio varied greatly among different localities. Its breeding population mainly consisted of males aged 5-10 years and females aged 8-13 years’old, which spawned in May each year.Females breed once with about 4 000 - 23 000 eggs produced every 2-3 years. Taimen grows fast and average growth rate is about 10 cm per year prior to 10 years’s old, which corresponded with von Bertelanffy’s equation calculated as L t=246 41[1-e -0 0407(t-0 4625) ] and W t= 174 075 72 [1-e -0 0407(t-0 4622) ] 2 9537 , and the relationship between body length and weight was W=0 015018L u 2020 .
文摘The sex ratio(♂/♀) of plateau pika′s(Ochotona curzoniae) population was studied by re-captured method in the region of the Haibei Alpine Meadow Ecosystem Research Station, Northwest Institute of Plateau Biology, the Chinese Academy of Sciences from April of 2001 to August of 2002. The result showed that there was no significant difference from 1∶1 in adult′s sex ratio in whole breeding season,whereas the sex ratio of juvenile had some fluctuations among different age stages. The sex ratio of the second litter varied significantly from embryo to 60-day-old, but no difference at the first and the third litter. We concluded it was caused by conflict between maternal strategy and juvenile′s strategy. No significant differences of sex ratio were found both in adult and juvenile between 2001 and 2002. The sex ratio of plateau pika before and after overwintering did not vary. In summary, we proposed that sex ratio of plateau pika′s population was not influenced by exogenous factors, but some self-regulation mechanisms may be involved.
