Variable habitat use by Japanese eel affects dissemination of swimbladder parasite Anguillicola crassus

摘要

Freshwater habitat use by yellow-stage eels is facultative. Survival, infestation rates, and prevcence of the swimbladder parasite Anguillicola crassus (Nematoda) in European eel is higher in freshw. ter than in brackish water or seawater. This suggests that infestation patterns vary among habitats with different salinity. To evaluate whether Japanese eel Anguilla japonica populations with different habitat use behavior have different parasite dispersion modes, we examined by electron probe microanalyzer the otolith strontium:calcium (Sr:Ca) ratios of 166 Japanese eels collected from the Kaoping River, southwestern Taiwan, in 2006 and 2007. According to the mean and SD of otolith Sr:Ca ratios, we differentiated between 3 types of habitat use in eels