Physiological status of wild European eels (Anguilla anguilla) infected with the parasitic nematode, Anguillicola crassus

The effect of the parasitic swimbladder nematode, Anguillicola crassus, on the physiological status of wild European eels (Anguilla anguilla) was inve stigated during an 18 month survey (February 1995 until September 1996), an d compared with that of wild uninfected eels collected over the same time-p eriod. Despite the occurrence of up to 15 blood-feeding adults in the swimb ladder lumen of the infected eels and as many as 25 additional larvae in th e swimbladder wall, there were no major differences in hormonal, metabolic or osmoregulatory status of the 2 groups of eels. Wild European eels appear to adapt to chronic parasitism with Anguillicola crassus. The possible adv erse effects of additional simultaneous stressors are discussed.