A quantitative video baseline survey of reef biota and survey of marine habitats within Bathurst Channel, Southwest Tasmania 2002

Abstract

Increasing visitation rates within Bathurst Harbour and Bathurst Channel in the Tasmanian Wilderness World Heritage Area have led to concerns that the unique and fragile marine invertebrate communities found there during recent studies may be irreversibly damaged unless the nature and location of threats were identified and managed. An important component of the management process is the establishment of a monitoring program to quantify the biological assemblages present and to detect any human impacts to these assemblages if they occur. This study has successfully established a quantitative baseline dataset on the horizontal and vertical distribution of invertebrate and algal assemblages within Bathurst Channel for use in on-going monitoring of change in the system. Robust estimates of the abundance of most conspicuous species have been obtained at selected sensitive sites (usually on hard substrates), allowing future changes and impacts to be detected and quantified. By utilising a combination of comprehensive quantitative surveys throughout the system and detailed habitat mapping, our understanding of the biological zonation within the system has been enhanced, along with our understanding of the limited extent of habitat available to many of the unique invertebrate assemblages. Specific recommendations arising from this study include: 1. ensuring baseline monitoring continues at an appropriate time-frame (perhaps every five years) 2. gaining a more detailed understanding of the faunal assemblages that occur within the soft sediment habitats that form the vast majority of cover within Bathurst Channel. 3. completing a biological census of the marine species of this area initiated in 1993, to ensure that where possible the distribution and abundance of unique, rare and endemic species can be adequately identified and mapped in subsequent surveys.