In Tasmania, there is a paucity of information on the life-history, population parameters and habitat requirements of fish associated with inshore soft-sediment habitats, particularly seagrasses. Clearly, such information is needed before stock assessment models can be developed, recruitment processes understood, key habitats identified and appropriate management measures developed to minimise impacts on these habitats. In order to examine the structure of fish communities in coastal soft-sediment habitats around Tasmania, the demersal and larger mobile fish fauna were routinely sampled from three areas-Norfolk Bay, Georges Bay and Prosser Bay. In each area, representative unvegetated (mud and sand) and seagrass habitats between 1 and 12 m deep were sampled seasonally.

In Tasmania, there is a paucity of information on the life-history, population parameters and habitat requirements of fish associated with inshore soft-sediment habitats, particularly seagrasses. Clearly, such information is needed before stock assessment models can be developed, recruitment processes understood, key habitats identified and appropriate management measures developed to minimise impacts on these habitats. In order to examine the structure of fish communities in coastal soft-sediment habitats around Tasmania, the demersal and larger mobile fish fauna were routinely sampled from three areas-Norfolk Bay, Georges Bay and Prosser Bay. In each area, representative unvegetated (mud and sand) and seagrass habitats between 1 and 12 m deep were sampled seasonally.

The fish fauna associated with Heterozostera seagrass and unvegetated habitats were compared in all three areas. Seagrass sites had a significantly higher abundance of demersal fish and a distinct community compared to unvegetated sites in Norfolk Bay and Georges Bay. In contrast, neither abundance or community composition differed between habitats in Prosser Bay. This pattern may be attributed to the patchy distribution of seagrass beds that result from the higher degree of exposure of the bay and the significant loss of beds over the past 20-30 years. Demersal fish in seagrass beds were dominated by small resident species, while those in unvegetated habitats were dominated by juveniles of larger species. Few larger more mobile species showed a distinct habitat preference. Unvegetated habitats were found to be more important than seagrass as a nursery area for juveniles of commercially important finfish species.