Mass Mortality of the Japanese Anchovy (Engraulis japonica) Caused by a Gill Monogenean Pseudanthocotyloides sp. (Mazocraeidae) in the Sea of Iyo (“Iyo-nada”), Ehime Prefecture
1984 Volume 19 Issue 2 Pages 119-123
Details
1984 Volume 19 Issue 2 Pages 119-123
From September to October, 1983, mass mortality of the anchovy Engraulis japonica occurred in the Sea of Iyo (part of Inland Sea; “Iyo-nada”), north of Sadamisaki Peninsula, Ehime Prefecture. Dead and dying fish were seen floating about thirty kilometers along the coast, and the number was estimated to be more than eighty-seven thouthand during that period. The common symptoms were gauntness and anemia. Out of 155 anchovies, 153 (99%) had a gill monogenean Pseudanthocotyloides sp. (Mazocraeidae), compared with much lower prevalence (0-17%) in the anchovy collected from several other localities in the prefecture. No bacterial infection was thought to be involved, and no extraordinary changes in the water quality were detected during that time. It is concluded that the mortality was caused by the monogenean.
