Study on the sex-related AFLP marker of the Yangtze finless porpoise

The sex-related molecular marker of the Yangtze finless porpoise was screened using Amplified Fragment Length Polymorphism （AFLP） technique combined with the bulked segregant analysis. Totally 36 AFLP primer combinations were used to detect the genome DNA bulks of the female and male porpoises, and one sex-related AFLP marker was finally obtained. The marker can be applied to sex identification, and provides a base for further cloning of sex-related genes and analyzing of Y chromosome haplotypes of the Yangtze finless porpoise.     

Genetic diversity in the Yangtze finless porpoise by RAPD analysis

To estimate the genetic diversity in the Yangtze finless porpoise ( Neophocaena phocaenoides asiaeorientalis), the randomly amplified polymorphie DNA technique was applied to examine ten animals captured from the Yangtze River. Out of 20 arbitrary primers used in the experiment, seventeen produced clearly reproducible bands. Calculated by Nei‘s formula d = 1-NAB/NT, the genetic distances ranged from O. 0986 to O. 5634. Compared with other cetacean populations, this genetic distance is quite low.Such a low genetic diversity suggests that this population may be suffering from reduced genetic variation,and be very fragile. More studies are needed for understanding the basis for this apparent low genetic diversity and to help protect this endangered, unique population.     

长江江豚保护生物学研究进展

近年来研究表明长江江豚(Neophocaena phocaenoides asiaeorientalis)是江豚(Neophocaena phocaenoides)的一个亚种,其种群数量明显减少,栖息地正在丧失。我国已有长江江豚30年饲养实践经验,建立长江豚类自然保护区,同时开展长江江豚饲养下的行为学与繁殖学研究,是保护本种积极有效的措施。     

半自然水域中长江江豚饲养水体理化因子分析

通过对夹江和长江铜陵江段水质监测,分析夹江水质理化因子的季节性变化规律,并与豚池及长江铜陵江段的水质进行比较,结果表明半自然水域中长江江豚饲养水体质量基本与长江相似,年均值基本符合地表水Ⅱ类标准,仅A区部分受到轻度污染。     

Population status, threats and conservation of the Yangtze finless porpoise

The Yangtze finless porpoise （Neophocaena phocaenoides asiaeorientalis） is currently limited to the middle and lower reaches of the Yangtze River from Yichang to Shanghai, China, and the adjoining Poyang and Dongting Lakes. Its population size has decreased remarkably during the last several decades due to the heavy impact of human activities, including overfishing of prey species, water development projects that cause attendant habitat loss and degradation, water pollution, and accidental deaths caused by harmful fishing gear and collisions with motorized vessels. It was estimated that the number of remaining individuals was down to approximately 1800 in 2006, a number that is decreasing at a rate as high as 5% per year. Three conservation measures - in situ and ex situ conservation and captive breeding have been applied to the protection of this unique porpoise since the early 1990s. Seven natural and two ＂semi-natural＂ reserves have so far been established. Since 1996, a small group of finless porpoises has been successfully reared in a facility at the Institute of Hydrobiology of the Chinese Academy of Sciences; three babies were born in captivity on July 5, 2005, June 2, 2007 and July 5, 2008. These are the first freshwater cetaceans ever born in captivity in the world. Several groups of these porpoises caught in the main stream of the Yangtze River, or rescued, have been introduced into the Tian＇e-Zhou Semi-natural Reserve since 1990. These efforts have proven that, not only can these animals survive in the area, they are also to reproduce naturally and successfully. More than 30 calves had been born in the reserve since then, with one to three born each year. Taking deaths and transfers into account, there were approximately 30 individuals living in the reserve as of the end of 2007. Among eight mature females captured in April 2008, five were confirmed pregnant. This effort represents the first successful attempt at off-site protection of a cetacean species in the world, and establishes a solid base for conservation of the Yangtze finless porpoise. A lesson must be drawn from the tragedy of Chinese River Dolphin （Lipotes vexillifer）, which has already been declared likely extinct. Strong, effective and appropriate protective measures must be carried out quickly to prevent the Yangtze finless porpoise from becoming a second Chinese River Dolphin, and save the biodiversity of the Yangtze River as a whole.     

基于腾讯位置大数据的长江经济带人口流动空间分析

在区域合作不断深化的背景下,人口在城市间高速流动,区域内城市的空间联系逐渐加强.城市间的人口流动具有动态性、时效性.目前基于统计年鉴的数据进行人口流动的分析具有迟滞性,因此基于腾讯位置大数据,运用Gephi复杂网络分析方法和GIS空间分析技术,对长江经济带的12个一线城市人口流动数据进行测度分析.结果表明,长江经济带城市人口联系度强度从东部向西部逐渐减弱,长江经济带城市人口流动量存在帕累托分布的“长尾分布”特征.长三角城市圈城市人口联系度高于武汉市城市圈和成渝城市圈,约为后面两个城市圈的2倍,区域地位优势明显.通过对长江经济带城市中心度分析,发现长江上、中、下游区域内存在不同的中心,长江上游主要以成都与重庆为区域中心城市,呈现双核心的空间结构;中游地区主要以武汉为中心,呈现一点多极的空间发展布局并有典型的“小世界”空间网络特点;下游主要呈现多中心集聚的空间分布特点.     

基于HJ-1卫星CCD数据的长江中游武汉河段悬浮物浓度反演

环境一号(HJ-1)卫星是我国自发研制的专门用于环境和灾害监测的光学卫星.其数据获取周期短、空间分辨率高,能及时、连续、准确地监测悬浮物浓度时空变化,在内陆二类水体遥感监测方面具有良好的应用前景.该文以长江中游武汉河段为研究区,利用HJ-1卫星CCD数据第1、3波段建立了具有较高精度的悬浮物浓度反演模型,并对2008年11月14日武汉河段悬浮物浓度进行了反演,得到其空间分布图.结果表明,该模型的悬浮物浓度反演均方根误差(RMSE)为8.84mg/L,平均绝对百分比误差(MAPE)为13.6%.从空间分布来看,在武汉附近,长江干流悬浮物浓度高于支流汉江,江心洲滩附近水体悬浮物浓度偏高.