Water and its role in aquatic environments

Water is the fundamental component of fish habitat, and factors related to its quality, quantity and timing are all important in relation to maintaining fisheries' productivity and aquatic biodiversity more generally, both in the freshwater system and in downstream estuaries.

River health and environmental flows

Many river systems in NSW have been dramatically altered over the last 200 years.  Construction of thousands of dams and weirs and water extraction has altered flow regimes, caused thermal pollution and blocked fish migration pathways. Sediment derived from catchment erosion, desnagging and clearing of riparian vegetation has also altered habitat quality. Introduced plants (e.g. willows) and fish (e.g. carp) have also contributed to a decline in river health and productivity. Many programs are now in place to address these issues.

• Rehabilitating aquatic habitats
• Fish habitat protection plans
• Threats to water quality, including cold water pollution
• Policies and guidelines for aquatic habitat management and fish conservation
• Aquatic weed control
• NSW Water Information (www.dwe.nsw.gov.au)
• Environmental rules for rivers (www.dnr.nsw.gov.au)
• Environmental monitoring (www.dnr.nsw.gov.au)
• Improving water quality and environmental flows (www.csiro.au/science)
• NSW Riverbank (www.decc.nsw.gov.au)
• The Living Murray (www.mdbc.gov.au)
• Maintaining in-stream life (www.rivers.gov.au)
• Planning for river restoration (www.rivers.gov.au)

Fisheries production

The production of fish, prawns and yabbies in rivers, lakes and estuaries is directly related to river flow and water quality. Both commercial and recreational fisheries depend upon seasonal variation in flows to induce spawning, growth of juveniles and replenishment of stocks.

• Inland Restricted Fishery
• Freshwater fish stocking
• Freshwater Fish Stocking Environmental Impact Statement and Fishery Management Strategy 
• Freshwater habitats

Aquaculture

Inland fish and yabby aquaculture depends upon access to good quality water.  Sydney Rock Oyster production is the largest aquaculture industry in NSW - it also depends upon regular freshwater flows to optimise growing conditions in coastal estuaries.

• Aquaculture
• Water quality management in aquaculture

Threatened aquatic species

The Department of Primary Industries has responsibility for threatened species, populations and communities of fish, aquatic invertebrates and marine vegetation. Water resource development, water extraction and alteration of river flow regimes has played a role in the decline of several species of freshwater native fish and invertebrates.

• Threatened species and key threatening processes
• Other protected species
• Species protection