新发现的江河寄生性等足类——细角鳃虫的人工感染试验

Artificial Infection with Rocinela sp.,the Newly Found River Parasitic Isopoda

珠江水系贺江段近年出现严重危害网箱养殖和江河鱼类资源的大型寄生虫病害．初步鉴定该虫隶属于甲壳纲．等足目．鳃虫科．细角鳃虫属．是国内新发现的淡水鱼类寄生虫。用该虫对草鱼、银鲫、麦鲮进行人工感染．结果表明：该虫具有很强的寄生能力．累积感染率为76．2％～100．0％；对寄生部位具有一定的选择性，以寄生在鳃部的比例（55．6％～72．0％）最大．胸鳍（11．7％～28．8％）次之；对试验鱼有较强的致死性；该虫吸血后体长（L）增长较大．体宽（W）基本不变；从寄主体上主动脱落的虫体，其L／W的增长率（16．32％～18．00％）较大，而一直寄生在寄主身上的虫体．其L／W的增长率则因各自摄食量的不同而存在较大的差异。

In recent years, a serious disease caused by a big parasite has occurred in Hejiang River of the Pearl River System, which has caused great harm to cage farming and natural fish resources. The parasite has been preliminarily identified as Crustaeea, Isopoda, Aegidae, Rocinela Leach and it was a newly found parasite of freshwater fish in China. This article reported the artificial infection with this parasite on grass carp （Ctenopharyngodon idella）, giebel earp（Carassius auratus gibelio）, and mrigal （Cirrhina mrigala）. The results showed that this parasite had very strong parasitic ability, the cumulative infection rate was 76.2%～ 100.0%. It had certain preference for parasitic sites, the gill ranked first （55.6%～ 72.0%）, followed by the pectoral fin （11.7%～ 28.8%）. The parasite also showed strong lethality in the tested fish. After sucking blood, the parasite had a higher increase of body length （L）, while it almost had no changes in body width （W）. The L/W of the parasites which left the hosts initiatively had higher increase rate （16.32%～18.00%）, while the L/W of those that stayed on the hosts all the time increased differently depending on the differences of individual feed intake.