Age, growth and reproduction of the Chinese minnow, Phoxinus oxycephalus in the Jiulongfeng Nature Reserve of the Huangshan Mountain

The age, growth and reproduction of Chinese minnow Phoxinus oxycephalus in the Jiulongfeng Nature Reserve of the Huangshan Mountain were examined. A total of 437 specimens were collected monthly from May 2011 to April 2012. The sex ratio was 0.77: 1, significantly differing from the excepted 1: 1 ratio. The population of P. oxycephalus was composed of three age groups for female and two age groups for male, and age 1 and age 2 were the dominant age groups in both sexes. Length growth was fastest in the first year while slowing in the second and third years. Fifty percent of individuals reached sexual maturity at age 1. Results from the monthly changes in gonadosomatic index (GSI) and the oocyte development process showed that the fish spawned from April through July. Absolute fecundity was relatively low, and increased with body size and varied between age classes, whereas no significant difference was observed in relative fecundity in relation to age class. Besides restricted distribution and small population, the relatively low fecundity of P. oxycephalus may suggest that this species is vulnerable to anthropogenic disturbance and environmental changes.