Polychaetes and amphipods as commensals with pagurids from the Alaska shelf

Abstract

Abstract Polychaetous annelids and/or amphipod crustaceans were associated with a total of 1715 (20.0 %) out of 8594 pagurids examined from the continental shelf of Alaska. Ten species of polychaetes (Eunoe depressa, E. nodosa, E. senta, Arctonoe vittata, Gattyana ciliata, Cheilonereis cyclurus, Eusyllis blomstrandi, Polydora commensalis, Lanassa venusta, and Crucigera zygophora) and at least three species of amphipods (Melita spp., Parapleustes pugettensis, and Podoceropsis nitida) were recorded with the following pagurids: Pagurus aleuticus, P. capillatus, P. confragosus, P. ochotensis, P. rathbuni, P. setosus, P. trigonocheirus, Elassochirus cavimanus, and Labidochirus splendescens. Eunoe depressa, Cheilonereis cyclurus, Polydora commensalis and Podoceropsis nitida have been previously reported with pagurids. A decrease in the frequency of occurrence of commensals with pagurids from the northeastern Gulf of Alaska to Norton Sound and an increase from the latter region to the southeastern Chukchi Sea was observed. An increase in dominance of one species of polychaete, Eunoe depressa, with pagurids was apparent from south to north. The commensals described with pagurids from Alaska are widely distributed in northern waters; thus, associations with pagurids are probable elsewhere.