溪流唐鱼种群时空格局及其主要影响因子
Temporal and Spatial Variations of Tanichthys albonubes Population in a Stream and the Main Affecting Factors

中文摘要：为探讨溪流濒危鱼类--唐鱼 Tanichthys albonubes种群的时空格局及其主要影响因素,首次采用分段围隔、全员捕捞、活体计数后全部放回的调查方法,对广东从化地区森林溪流塘肚溪的唐鱼种群做了周年调查,同时测定了浮游生物、水温及水流量等环境指标。结果显示,塘肚溪唐鱼种群数量以7月(3694尾)和10月(3829尾)最多,2月(166尾)最少。种群年龄组成在3-11月以仔、稚鱼数量居多,1-2月仔、稚鱼则绝迹。唐鱼种群数量空间分布特征为上段、下段大于中段,水坑、缓流区大于急流区。仔、稚鱼和幼鱼主要栖息在水坑和缓流区,成鱼则在各区域均有分布。塘肚溪水温1月最低(13.4℃),8月最高(26.4℃);水流量变化特征为春、夏季高,冬季低。浮游生物数量时空变化明显,8月密度达到最大值(浮游植物132.6×10 3ind·L -1,浮游动物148 ind·L -1),最低值出现在1月(浮游植物6.81×10 3ind·L -1,浮游动物37 ind·L -1);空间变化表现为水坑和缓流区密度大于急流区。唐鱼种群数量与水温、水流量的时间变化及浮游生物密度时空变化均呈显著正相关( P<0.05)。研究结果表明,唐鱼种群的时空格局变化明显,并受到水温、水流和作为饵料的浮游生物的影响;水温和水流量影响唐鱼数量的时间变化,流速则影响唐鱼的空间分布,而浮游生物与唐鱼种群的时空变化均有密切的关系。
英文摘要： Tanichthys albonubes, an endangered stream-dwelling species of China, was investigated for 12 months in Tangdu Stream, a forest stream of Conghua, Guangdong province, China. The study aimed to explore the spatial-temporal variations in the population of this species and the main contributing factors. The fish were captured, counted, and then released. In addition, plankton density, water temperature and water flow were surveyed. The results showed that the largest population size of T. albonubes appeared in July (3694 ind.) and October (3829 ind.), whereas the smallest was in February (166 ind.). The larvae flourished between March and November but disappeared from January to February. T. albonubes mainly inhabited upstream and downstream. Larvae and juveniles of T. albonubes preferred the habitats with puddles and slow flow rate while the adults mainly distributed in the reaches with different flow rates. The lowest water temperature (13.4℃) was observed in January and the highest (26.4℃) was in August. Water flows were high during spring and summer while low in winter. Marked spatial and temporal differences were reflected by plankton density. The maximum biomass (phytoplankton density was 132.6×10 3 ind·L -1; zooplankton density was 148 ind·L -1) was seen in August and the least (phytoplankton density was 6.81×10 3 ind·L -1 and zooplankton density was 37 ind·L -1) in January, and there was more plankton in the puddles and slow flow areas than in the rapids. A strong positive linear correlation was observed between the population size of T. albonubes and water temperature and water flow in temporal variation and plankton density in spatial-temporal variation ( P<0.05). These findings indicated that the population of T. albonubes, which was affected by the water temperature, flow rate and plankton density, changed spatially and temporally. Water temperature and water flow influenced the annual variation of T. albonubes population, and