著者

Tomomichi Ohtani Izumi Kawamoto Masamitsu Chiba Noriyuki Kurono Satoru Matsuoka Kazuo Ogawa

出版者

The Japanese Society of Fish Pathology

雑誌

魚病研究 (ISSN:0388788X)

巻号頁・発行日

vol.56, no.2, pp.43-52, 2021-06-15 (Released:2021-07-02)

参考文献数

24

被引用文献数

1

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Long-term parasitological surveys were conducted on the isopod Ceratothoa verrucosa infecting red seabream Pagrus major caught in Iyo-Nada, Ehime Prefecture during the period of 2003–2007. ​The isopods were almost always in a pair of a male and a female, attached to the buccal cavity wall. ​The earliest infection occurred when seabream was 0+ year-old and the isopods grew as host fish grew. ​Prevalence of infection ranged from 12.2% to 21.2% when the host was 0+ to 5-year-old and decreased to 3.4% at 6-year-old and no infection among 7-year-old and older fish. ​These results suggest that infection was established when the host was 0+ year-old, and their life span of C. verrucose was estimated to be up to 6 years. ​Infected fish sometimes showed deformation in the upper jaw and growth retardation, but there was no evidence of infection-related mortality. ​The main reproduction season of the isopod was in summer, estimated by the presence of manca larvae in the marsupium of the female. ​Sometimes the monogenean Choricotyle elongata attached to the pleotelson of C. verrucosa. ​Prevalence and abundance of the monogenean were higher in the hyperparasitized seabream than in the fish without isopod infection, suggesting that the isopod favored the monogenean infection.