广东省主要水系罗非鱼的建群状况

The study of population establishment of tilapia in main rivers in Guangdong Province, China

【背景】罗非鱼是华南地区自然水域的常见种,是我国主要的外来鱼类之一,但对其在自然水域的分布和数量缺乏详细的描述。【方法】对广东省的主要河流珠江(西江、北江、东江)、韩江、鉴江和潭江等的多个样点进行了调查,主要对各样点渔获物中罗非鱼的比例进行了统计,并对各种群的年龄结构、性比、性腺发育和食性等进行了研究。【结果】广东省各主要水系均有罗非鱼野生个体的存在,其中,鉴江袂花江段数量最多,约占渔获物总质量的60%,西江、北江数量相对较少,不到渔获物总质量的1%;在各种群中均发现了2龄以上个体和性成熟个体,并在调查中采集到大量仔、幼鱼。【结论与意义】以上结果表明罗非鱼在广东各主要河流已能完成越冬和繁殖,并建立自然种群。

[ Background] As an alien species, Tilapia sp. is widely distributed in South China, yet a detailed description on the dis- tribution and abundance in natural waters is lacking. [ Method ] We surveyed tilapias in the main rivers of Guangdong Province, inl- cuding the Pearl River tributa （Xijiang River, Beijiang River, Dongjiang River）, Hanjiang River, Jianjiang River and Tanjiang River, in order to clarify the distribution and the invasion situation. We collected data on the age structure, sex ratio, sex develop- ment, and feeding habits. [ Result] Tilapia was found in the major rivers of Guangdong Province and it has a stable, self-sustaining populations. The Jianjiang River has the largest number, accounting for approximately 60% of the total fisheries catch by weight. The Xijiang and Beijiang Rivers have smaller numbers and contributes 〈 1% by weight. In these rivers, many 2 y old individuals and mature individuals were found in each population and a large number of juveniles were also collected. [ Conclusion and signifi- cance] Tilapia has established natural populations in the major rivers in Guangdong Province because it has been able to overwinter and reproduce in natural waters.