A new secondary ecotope for talitrids: driftwood in the Bay of Fundy

Abstract

Platorchestia platensis (Amphipoda, Talitridae) was previously known ecologically as a wrack generalist, but here we describe a secondary driftwood ecotope for this species. The trophic dependence of driftwood-acclimated P. platensis on rotting wood was confirmed by successfully culturing it within driftwood, without further addition of food. The stranded driftwood in which P. platensis was found contained gribble burrows (round and of 0.6 to 5 mm diameter). We hypothesize that P. platensis used the empty gribble burrows for interspecific squatting (to gain initial entry to driftwood and for shelter). We found eleven driftwood depositories in a 230 km length of shoreline in Passamaquoddy Bay. The commonest driftwood was of spruce and eastern white cedar. The small marsh at Hartley Cove contained a driftwood depository, where the new driftwood ecotope was discovered. This site was studied temporally to understand how wind and tidal forces might affect import and export of driftwood.