Abstract
The nematodes Cucullanus hians, Cucullanus longispiculum , Cucullanus minutus , Contracaecum sp., Anisakis simplex , and Cristitectus congeri , the cestodes Grillotia , sp. and Scolex pleuronectis , and the acanthocephalan Acanthocephaloides propinquus , were recorded from 251 conger eels from the Muros and Arousa estuaries, north‐west Spain. Several species were useful as tags and showed that conger eels in both estuaries and also on the continental shelf belong to separate populations. The nematode C. congeri , shows a distribution pattern indicating that the trophic chains involving the conger eel in each estuary are probably different. The species composition and abundance of the nematode, cestode and acanthocephalan fauna of Conger conger , on the north‐west Spanish coast may depend more on population isolation and variations in trophic chains between the sites studied than on the particular environmental conditions of the sites.