Abstract:
Surveys of subtidal rocky reefs were conducted in the Kent Group Marine Nature Reserve and adjacent external reference locations as part of a broader study into the effectiveness of marine protected areas (MPAs) in Australian temperate waters. Surveys were undertaken with an identical methodology to that applied in corresponding studies in Western Australia, South Australia, Tasmania, New South Wales and Victoria. Surveys assessed fish size, diversity and abundance, as well as macro invertebrate and algae abundance.
Baseline surveys of Tasmania's Kent Group Marine Nature Reserve were conducted in June 2004 (20 replicate sites), June 2005 (29 replicates) and June 2006 (29 replicates). These surveys complimented prior baseline studies undertaken in 1992 and 2000. Zoning was implemented in the marine nature reserve in February 2005.
The surveys have recorded a highly diverse fish fauna, dominated by Notolabrus fucicola (Purple wrasse) and Notolabrus tetricus (Blue-throat wrasse), and strongly influenced by NSW species, including species not previously encountered during earlier studies (e.g. Eastern blue grouper and Crimson banded wrasse). Mobile invertebrate assemblages were dominated by Haliotis rubra (blacklip abalone), Heliocidaris erythrogramma (Common urchin) and Centrostephanus rodgersii (Long-spine urchin) but included a broad range of other mobile invertebrate species including species not typically found in more southern Tasmanian waters such as Nectria machrobranchia, and N. multispinna. Centrostephanus forms extensive barren areas within the Kent Group, however there is little evidence of numbers or barrens increasing from 1992 levels, despite increasing numbers of other predominantly NSW species over this time. The algal community was relatively diverse with Ecklonia radiata and Phyllospora comosa dominating the canopy cover at most locations. The red algae Pterocladia capillaceae was notable in that it formed a distinctly greater component of the flora than in other locations surveyed in Tasmanian waters.
The survey methodology is designed to detect changes at all levels of species interaction and the response of each management zone (no take and restricted take) to protection. Ideally surveys will continue to be repeated each year, producing a time-series of data documenting changes in the abundance and size distribution of species of interest. This will allow clear trends through time in protected zones to be differentiated from chance divergence, providing an indication of MPA performance and a reference role for assessing the extent of fishing related system and species changes in north-eastern Tasmanian waters.
