Li Xinhui

Species diversity of fish community of Provincial Xijiang River Rare Fishes Natural Reserve in Zhaoqing City, Guangdong Province

Survey aiming at the wild fish resources in Provincial Rare Fishes Natural Reserve of Xijiang River in Zhaoqing City. 81 fish species belonging to 11 orders, 25 families and 69 genera from 2006 to 2008, among them there are 8 river-sea migratory species, 6 exotic species and 67 native freshwater species. Analysis of the species numbers and diversity indices showed that fish diversity of the Reserve was high. Cirrhina moitorella, Squaliobarbus curriculus and Megalobrama hoffmanni were the preponderant species. Megalobrama hoffmanni, Squaliobarbus curriculus, Cirrhina moitorella, Xenocypris davidi and Clupanodon thrissa are the primary economic fishes. The rare fishes such as Anguilla marmorata, Cranoglanis bouderius bouderius, Parabramis lineatus and a lot of species only distributed in Pearl River water system can be seen there. The fish stocks of the Reserve belong to different ecological types in their migration, feeding and inhabitation. Fish communities were dominated by sedentary species (72.8%) of the community, omnivore species (51.9%) and sub-stratum species (50.6%). Xijiang River Rare Fishes Natural Reserve is perfect area for fish living due to its special hydrodynamic environment and complicated riverbed geology. Habitat destroying and excessive catching are the key factors to impact decreases of the fish diversity. Keyword: Xijiang River; Natural Reserve; diversity 西江珍稀鱼类省级自然保护区位于广东省肇庆市封开县西江青皮塘江段(图 1), 地理坐标为北纬 23°24′43′′-23°17′13′′、东经 111°29′14′′-111°29′32′′, 属于重要水生动物主要栖息地、繁殖地、洄游通道 * 中 国水 产科学 研 究院 内陆 渔业 生 态环 境和 资源 重 点开 放实 验室 开 放基 金 (YM2007-05)、 广东 省科 研 计划 项目 (2004B33301015)、科技部公益专项(2005DIB3J023)和广东省海洋与渔业局保护区管理项目联合资助. 2008-06-26 收稿; 2009-02-17 收修改稿. 李捷, 男, 1979 年生, 硕士, 助理研究员; E-mail: lijie1561@163.com. ** 通讯作者; E-mail: lxhui01@ tom.com. 李 捷等: 广东肇庆西江珍稀鱼类省级自然保护区鱼类多样性 557 类型自然保护区. 西江源出云南沾益马雄山, 流经贵州和广西, 在梧州与桂江汇合后进入广东境内始 称西江. 西江地处亚热带, 气候温和, 雨量充沛, 河水丰盈, 上游带来的泥沙、矿物质和有机物含量较大, 饵料资源丰富, 生态环境适合鱼、虾、蟹、贝类生长, 鱼类资源十分丰富. 20 世纪 80 年代, 珠江水产研 究所等单位对西江渔业资源进行大规模调查, 记录鱼类 136 种, 并发现西江青皮塘和罗旁江段是广东 鲂产卵场, 广东鲂具有集群产卵的习性, 每年 4-5 月产卵场区域形成渔汛, 由于对产卵群体的过度捕捞 造成广东鲂资源急剧衰竭, 为恢复和保护广东鲂资源, 肇庆市渔政支队于 1992 年在广东鲂产卵期对产卵 场实施禁渔保护, 封开县人民政府颁布了产卵期禁捕公告. 为配合广东鲂产卵场的生态保护, 农业部珠 江流域渔业生态环境检测中心对产卵场生态进行长期跟踪检测, 使广东鲂资源不断得到恢复. 2004 年 产卵场禁渔区被升级为肇庆市级自然保护区, 2008 年升级为省级自然保护区. 鱼类多样性研究始于 20 世纪 60 年代, 我国至 20 世纪 80 年代才见报道, 但对江河淡水鱼类多 样性研究仍很少. 近年来, 由于人类涉水活动影响, 江河水生生态环境遭受严重破坏, 鱼类生物多样性 不断下降, 人们逐渐意识到生物多样性保护的重要性, 江河鱼类多样性研究成为热点. 有关西江鱼 类多样性研究未见报道, 因而开展西江肇庆市珍稀鱼类自然保护区鱼类多样性研究, 摸清楚保护区江段 鱼类本底资料, 对西江生物多样性保护、合理利用鱼类资源、优化鱼类群落结构、探讨鱼类群落演替规 律与环境的关系等方面具有重要意义. 图1 肇庆西江珍稀鱼类省级自然保护区位置 Fig.1 Location of Provincial Xijiang River Rare Fishes Natural Reserve in Zhaoqing City

Hydroacoustic assessment of fish resources in the Lake Qinghai with EY60 echosounder

A SIMRAD EY60 echo-sounder with 200kHz split-beam transducer was used to survey the fish school in Lake Qinghai on August 16-18, 2006. The transducer was tied on the side of the ship downward at one meter depth. The cruising speed is 8-10km/h. Also, a GPS was connected with EY60 echo-sounder for obtaining the survey position data. The pulse duration was set at 64μs. At post-processing, the Sonar5-pro software (versions 5.9.6) was used to analyze the echo-sounder data. The results show that the Gymnocypris przewalskii is not uniform distribution in horizontal direction in Lake Qinghai, and appears the feature of small aggregation. For different survey subarea, the density of fish is 0.168-12.8ind./1000m3, and the average is 1.16ind./1000m3 where the maximum appeared near the Buha estuary. The biomass of catchable size is estimated at 6.5×107ind. near 15275 ton, at 35.6×107-118.4×107ind. with 95% confidence interval. Our results also indicated that the EY60 echo-sounder is suitably applicable in Lake Qinghai to estimate the fish productions effectively.