Utilisation of the introduced New Zealand screwshell (Maoricolpus roseus) by native hermit crabs in eastern Tasmania - depth-related variance in shell occupancy

Interactions between native and introduced species can help to elucidate the impact of exotic species on the broader community. This work examines utilisation of an introduced gastropod, the New Zealand screwshell (Maoricolpus roseus) by native hermit crabs in eastern Tasmania.Variation in shell occupancy by hermit crabs was examined across different depths (10, 20, 30 and 40m) within a single site (Dennes Point, SE Tasmania). Sediment cores were taken from 10 and 20 m to compare sediment size structure. A sediment preference trial using the hermit crab Paguristes tuberculatus was also carried out (using sediment from 10m and 20m) to try and determine the low level of hermit crab occupancy at 20m (compared with that at 10m).