尼罗罗非鱼早期发育形态及其在珠江水系的空间分布

【背景】罗非鱼作为联合国粮农组织（FAO）向全世界推广养殖的优良品种之一，有多个品系，其养殖范围已遍布85个国家和地区。1956年我国从越南引进莫桑比克罗非鱼，经过养殖及推广，2006年我国罗非鱼产量达到100万t。但是，该外来物种在给我国带来良好经济价值的同时，对土著种类及水环境造成了极大的影响。【方法】对近几年珠江水系渔获物的调查数据进行整理，并观察尼罗罗非鱼早期发育形态，统计尼罗罗非鱼苗对其他鱼苗的最大捕食量及捕食规格，以分析罗非鱼生物学特性及其在珠江水系的入侵现状。【结果】尼罗罗非鱼早期发育快，卵黄营养非常丰富，比珠江水系土著种类更有竞争性；罗非鱼苗呈现很强的攻击性与捕食性；尼罗罗非鱼已经扩散到珠江水系各主要河流，并在部分江段形成优势种群。【结论与意义】尼罗罗非鱼种群快速扩张，对土著种已构成严重威胁，有必要将其列为珠江水系高危入侵种。

Early development and spatial distribution of the Nile tilapia (Oreochromis niloticus) in the Pearl River

Background] With assistance by the Food and Agriculture Organization of the United Nations （FAO）, tilapia were intro- duced into more than 85 countries of the world. In 1956, tilapia was introduced to China, and tilapia production increased to million tones in 2006. Aside from its value as an important aquaculture species, the tilapia is sometimes problematic to native fish. Meth- od ] We observed the early development of the Nile tilapia, and its predation on native fish. Additionally, we analyzed the distribu- tion of Nile tilapia in the Pearl River using the data from fishery investigations and other literature. Result] Nile tilapia larvae de- velop quickly, with sufficient yolk nutrition. Tilapia fry can prey on native fish larvae. It is clear that Nile tilapia have spread throughout the length of the Pearl River, and is very common in some sections. Conclusion and significance ] As native fishes are being threatened by the tilapia, it should be regarded as a dangerous invader in China.