Repairing Australia's estuaries for improved fisheries production – what benefits, at what cost?

Abstract

An Australia-wide assessment of ~1000 estuaries and embayments undertaken by the National Land and Water Resources Audit of 1997–2002 indicated that ~30% were modified to some degree. The most highly degraded were in New South Wales, where ~40% were classified as ‘extensively modified’ and <10% were ‘near pristine’. Since that review, urban populations have continued to grow rapidly, and increasing pressures for industrial and agricultural development in the coastal zone have resulted in ongoing degradation of Australia's estuaries and embayments. This degradation has had serious effects on biodiversity, and commercial and recreational fishing. A business case is developed that shows that an Australia-wide investment of AU$350 million into repair will be returned in less than 5 years. This return is merely from improved productivity of commercial fisheries of a limited number of fish, shellfish and crustacean species. Estuary repair represents an outstanding return on investment, possibly far greater than most of Australia's previous environmental repair initiatives and with clearly demonstrated outcomes across the Australian food and services economies.

‘Bright spots’ for estuary management in temperate Southern Australia

“…52 There is limited ecological information for many of Tasmania's estuaries except for the major river-fed systems that include Huon, Derwent, Tamar and Bathurst Harbour. 53 Tasmania's estuaries and adjoining embayments are of economic value to mariculture and other forms of aquaculture, specifically Pacific oysters, abalone, scallops, mussels and salmon farming. 54 Since the establishment of shellfish culture in the 1960s, followed by finfish farming in the 1980s, the growth of mariculture has not followed a specific planning process, resulting in ad hoc approaches to the industry's development.…”

“…50 Tasmania's estuaries range from near pristine condition in the south-west to estuaries that are heavily modified and impacted by excessive sediment and nutrient export from upstream catchment activities along the eastern coastline. 51 Estuary wetlands consisting of saltmarsh and fresh to brackish sedge lands are dominant in Tasmania's estuaries; however, the majority of these have been modified in some form due to land clearing for agriculture and urban development. 52 There is limited ecological information for many of Tasmania's estuaries except for the major river-fed systems that include Huon, Derwent, Tamar and Bathurst Harbour.…”

“…51 Estuary wetlands consisting of saltmarsh and fresh to brackish sedge lands are dominant in Tasmania's estuaries; however, the majority of these have been modified in some form due to land clearing for agriculture and urban development. 52 There is limited ecological information for many of Tasmania's estuaries except for the major river-fed systems that include Huon, Derwent, Tamar and Bathurst Harbour. 53 Tasmania's estuaries and adjoining embayments are of economic value to mariculture and other forms of aquaculture, specifically Pacific oysters, abalone, scallops, mussels and salmon farming.…”

“…10 One result has been habitat loss; for example, 17% of mangroves and 21% of saltmarsh have been lost in New South Wales (NSW) and Victoria alone 11 while oyster reefs in south-east and southwest Australia have been reduced to the extent that they are considered functionally extinct. 12 Of all states and territories, NSW contains the highest number of degraded estuary systems, with 40% classified as extensively modified and less than 10% being in near pristine condition. 13 This extent of habitat loss has serious impacts on biodiversity and commercial and recreational fishing.…”

Baseline survey of the fish fauna of a highly eutrophic estuary and evidence for its colonisation by Goldfish (Carassius auratus)

“…It is widely recognised that, despite their many valuable ecosystem services (Costanza et al 1997;Creighton et al 2015;Sheaves et al 2015), temperate estuaries are the most degraded of all aquatic ecosystems (Jackson et al 2001). Microtidal systems, i.e.…”