Victoria Province, Australia
O'Hara, T.D. (2000). Victoria Province, Australia, in: Sheppard, C.R.C. (Ed.) Seas at the millennium: an environmental evaluation: 2. Regional chapters: The Indian Ocean to The Pacific. pp. 661-671
In: Sheppard, C.R.C. (Ed.) (2000). Seas at the millennium: an environmental evaluation: 2. Regional chapters: The Indian Ocean to The Pacific. Pergamon: Amsterdam. ISBN 0-08-043207-7. XXI, 920 pp., more
|
| Available in | Author |
|
Document type: Review
|
| Abstract |
This chapter describes the state of the marine environment in Victoria and adjacent waters. The open coast is dominated by rocky reef, sandy beaches and a range of offshore soft sediment habitats. There is a diverse benthic biota on the continental shelf and slope, with extensive sponge beds occurring in Bass Strait. The marine embayments and estuaries support extensive seagrass beds, mud£lats, mangroves and saltmarsh. The bays and many estuaries have been profoundly changed by human activities, including the opening of new entrances to the sea, draining of wetlands, clearing of vegetation in the catchment, by urbanisation, and the increased use of agricultural fertilisers. Increased nutrient levels and turbidity have led to seagrass dieback and algal blooms in some inlets. Seagrass loss was extensive during 1975-1984, when Western Port Bay lost 70% of its cover and Corner Inlet 25%. The Gippsland Lakes have been adversely affected by reduced freshwater input, increased levels of nutrients, algal blooms and damage to aquatic vegetation from the introduced European Carp. In Port Phillip Bay nutrient levels have declined since the 1960s following additional sewerage treatment and diversions. Toxicant levels are also declining but remain a localised problem around some outlets. Some fisheries are over-exploited, most notably for scallops, Southern Rock Lobster and Snapper. Trends in other commercial fisheries are masked by the natural variability of fish abundance and changes over time in fishing effort and technologies. Several fish species, favoured by recreation fishers, have declined in numbers in Port Phillip Bay since 1972, probably due to over fishing. Offshore there are concerns about damage to seafloor habitats from trawling and dredging. Over 175 introduced and cryptogenic species have been reported from Port Phillip Bay, more than any other port in the Southern Hemisphere. Several of these species now occur in large numbers and are considered significant pests or weeds. |
|
