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Issues Water Quality
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This chapter gives an overview of the coastal, estuarine and marine environments of Tasmania, highlighting the current understanding of environmental conditions and trends. It aims to provide a holistic overview of the state of these environment, the pressures affecting them, and management and community responses to these pressures. The chapter focuses on changes since the first SoE Report for Tasmania (SDAC 1997), although earlier baselines are used where data are available and relevant for describing conditions, trends and changes in the environment. The key issues that are discussed in the chapter can be accessed from the menu on the left of this page. This will take the reader to the summary 'At a glance' section for the particular issue selected. For a more in-depth analysis, 'Issue Reports' can also be accessed from these summary sections (follow the 'Continued in depth' link). All chapter content-including indicators, case studies and recommendations-can be accessed through these Issue Reports. A brief summary of the key findings of the Coastal, Estuarine and Marine Chapter, with links back to the related Issue Reports, is available. It includes information on the conditions and trends and what has been achieved since the previous SoE Report. Various lists of the Coastal, Estuarine and Marine Chapter content are also available to assist in providing an overview of the chapter. An index of the indicators used within the Coastal, Estuarine and Marine Chapter is included. Various case studies relevant to the issues within this chapter are provided. A number of recommendations are also presented for this chapter. Tasmania has more coastline per unit land area than any other State in Australia-about 4,900 km, not including Macquarie Island (Australian Surveying and Land Information Group 1993). No place in Tasmania is more than 115 km from the sea and most population centres and major industries are on, or near, the coast. The principal landmass is surrounded by islands, and is cut by a myriad of bays and estuaries. Describing the diverse coastal, estuarine and marine environments of Tasmania's coastline is a challenge, for they include rocky reefs, sandy beaches, sea cliffs, headlands, river estuaries, harbours and open coast. As is the case generally in Australia (Zann 1995), Tasmania's marine environment is incompletely described. Its rich variety of marine life includes delicate basket stars and sea dragons, kelp forests, seagrass beds, sponge gardens, rarely seen endemic handfish, crustaceans, plankton, fairy penguins, great white sharks and migrating whales. At the time of the first SoE Report for Tasmania (1997), a detailed assessment of the state of the marine environment was limited by this absence of baseline studies (both past and present) by which changes from the existing state can be measured. This absence of data was principally due to the difficulties and costs of working in the marine environment, and a community perception that the oceans are sufficiently large to absorb human impacts. Consequently, many older studies were of the taxonomy, distribution and biology of individual species, and were done by universities. In the five years since the previous SoE Report, baseline conditions have been established for estuarine water quality (Murphy et al. 2003) and assessments have been undertaken of estuarine condition, type and naturalness (Edgar et al. 1999). In 2000, a detailed and comprehensive sea floor habitat-mapping program-Seamap Tasmania- commenced. The first series of maps from this program reveal the extent of some habitats for the first time. In late 2003, the second State of the Derwent Report was released. Some researchers have been able to identify baseline conditions over a much longer period of time. Catastrophic losses of shell (molluscan) species over the past 150 years in the shallow, sheltered estuarine waters of the south-east have been documented (Samson & Edgar 2001). The losses were previously undetected, which highlights the risk of the 'sliding baseline syndrome' where changes that occur over generations are not noticed and the new environmental conditions are thought of as 'normal' (Dayton et al. 1998). While the ability to assess and measure the current situation and changes remains constrained by a limited and fragmented information base, significant improvements in understanding have occurred as a result of the work of these programs and initiatives. The Coastal, Estuarine and Marine Chapter provides an overview of the condition of the coastal, estuarine and marine environment, and the human activities, which act as major agents of change. Many people and organisations have assisted greatly in compiling the State of the Environment Report. For this chapter, the Commission would like to acknowledge the kind assistance of the following: Tony Davidson, Greg Dowson, Cathi Greve, Alan Jordan, Bonnie Lauck, Helen Locher, Alice Morris, Richard Mount, Ray Murphy, Chris Rees, Nigel Townshend, Stephen Waight, Fiona Wells, Graham Woods. |
