6.8 Aquatic species diversity

No additional species have become extinct since 2003, but there have been five new listings of threatened aquatic species, populations and communities under the Fisheries Management Act 1994. Eleven aquatic or wetland species and eight endangered ecological communities that are predominantly or partially aquatic have been listed over the same period under the Threatened Species Conservation Act 1995.

While aquatic species diversity in NSW remains under threat, knowledge about the scale of the problem is growing, with better processes in place for recognising and assessing species and communities at risk.

Far-reaching legislative changes to protect biodiversity and habitat have been introduced. Many of these address the threats and processes that drive the decline in biodiversity.

The preparation of recovery plans is well advanced for most of the aquatic species listed as threatened under the Fisheries Management Act 1994 and three plans were approved recently.

NSW indicators

Introduction

Aquatic species play a crucial role in maintaining ecological processes. Loss of species diversity weakens natural ecosystems and diminishes ecosystem services, which can have significant ecological, economic and social impacts.

Current status and trends

Around 16% of the State's native freshwater finfish species are listed as threatened under the Fisheries Management Act 1994 (FM Act), compared with less than 1% of marine fish species (Table 6.20). This may be because freshwater habitats have been more highly modified by human activities than most marine environments. Invertebrates and algae have not been well documented and are probably under-represented in threatened species listings.

Table 6.20: Aquatic species, populations and ecological communities listed as extinct or under threat in NSW

Source: Listings under the FM Act (Department of Primary Industries data, January 2006), except marine mammals, which are listed under the Threatened Species Conservation Act 1995 (DEC data January 2006).

A range of aquatic species has also been listed under the Threatened Species Conservation Act 1995 (TSC Act), including 31 marine species, mainly birds, but also seven mammals (the dugong, two fur seals and four whales), three turtles and a saltmarsh plant. Of these, only the mammals are included in Table 6.20. The remaining species appear in Table 6.7 (see Biodiversity 6.3).

Since 2003 a range of new terrestrial aquatic and wetland species has also been listed as threatened under the TSC Act. These include four frog species, one bird, five swamp or water plants and eight endangered ecological communities.

The three endangered ecological communities listed under the FM Act cover the majority of western-flowing streams in NSW, divided regionally into the lower Murray and Murrumbidgee river catchments, the Lachlan River catchment, and the Darling River catchment.

The FM Act also provides for the identification and listing of key threatening processes that affect threatened species, populations and communities. Seven are currently listed under the FM Act:

• degradation of native riparian vegetation along NSW watercourses
• hook-and-line fishing in areas important for the survival of threatened fish species
• installation and operation of instream structures and other mechanisms that alter natural flow regimes of rivers and streams
• introduction of fish to waters within a river catchment outside their natural range
• introduction of non-indigenous fish and marine vegetation to the coastal waters of NSW
• removal of large woody debris from NSW rivers and streams
• the current shark meshing program in NSW waters.

There is some overlap between these and the four aquatic key threatening species listed under the TSC Act:

• alteration to the natural flow regimes of rivers and streams and their floodplains and wetlands
• death or injury to marine species following capture in shark control programs on ocean beaches
• entanglement in, or ingestion of, anthropogenic debris in marine and estuarine environments
• predation by the plague minnow (mosquito fish).

The NSW Rivers Survey examined freshwater fish communities across NSW over a two-year period in the mid-1990s and concluded that there was a decline in the biodiversity of the State's riverine ecosystems (see Water 2.1). The decline was particularly apparent in the Murray region and in rivers that are regulated for water supply (Harris & Gehrke 1997). Nearly 30% of the 55 species of native freshwater fish in NSW were not observed in these surveys (Harris & Gehrke 1997; NSW Fisheries 2000).

Subsequent surveys of fish species and aquatic habitats confirm the earlier findings. The distribution of some species previously common across NSW is now restricted, including the olive perchlet, freshwater catfish, and short-finned eel. The abundance of many other native fish, including silver perch and river blackfish, is also decreasing. Physical deformities are recorded during surveys, with up to 25% of fish showing evidence of parasites and disease (Morris et al. 2001; Pogonoski et al. 2002; Gilligan 2005a; Gilligan 2005b).

Response to the issue

The FM Act provides for the listing of threatened aquatic species, populations and ecological communities, and key threatening processes, and their management through recovery plans and threat abatement plans. The Act covers the listing of extinct, endangered and vulnerable fish, invertebrates (including molluscs and crustaceans) and marine vegetation. Most other fauna, including marine mammals (such as whales and seals), birds, reptiles and amphibians are protected under the TSC Act.

The Threatened Species Legislation Amendment Act 2004 introduced a suite of changes to the threatened species provisions of the FM Act (see Biodiversity 6.3). These included:

• the development of the Priorities Action Statement outlining the Government's priorities for protecting threatened biota and dealing with key threatening processes listed under the FM Act, and performance indicators for reporting on progress
• establishment of planning instruments that limit the application of the threatened species provisions in prescribed situations
• introduction of three additional listing categories – critically endangered species, critically endangered ecological communities and vulnerable ecological communities
• enhanced transparency in the processes for listing threatened species.

Under the legislative changes the preparation of recovery plans is no longer mandatory for all species listed as threatened under the FM or TSC Acts. Threat abatement plans must be consistent with the Priorities Action Statements.

However, recovery plans have been finalised under the FM Act for the eastern (freshwater) cod, Oxleyan pygmy perch, silver perch and trout cod. Drafts for three other species and the endangered ecological community of the lower River Murray catchment are in the final stages of preparation. Work on recovery plans for another five fish species is also underway.

Recovery plans are also being prepared for four species of whale listed under the TSC Act: the blue, southern right, humpback and sperm whales (NPWS 2000).

A draft threat abatement plan has been prepared to address the 'removal of large woody debris from NSW rivers and streams', and the 'degradation of native riparian vegetation along NSW watercourses'.

An extensive recovery program is underway for the grey nurse shark and great white shark, involving tagging, tracking, documentation of reproductive cycles and a project to examine the feasibility of a breeding program for grey nurse sharks.

The NSW Government banned the commercial fishing of native freshwater finfish in 2001. It also conducted a comprehensive environmental impact assessment on the stocking of freshwater fish and approved a management strategy modifying stocking practices. Stocking programs are conducted to conserve trout cod, eastern cod and purple-spotted gudgeon. A plan is also being prepared for the management of recreational fishing to assist in protecting freshwater fish stocks.

Fish habitat protection plans provide protection for specific aquatic habitats, and public authorities are required to take them into account in their decision-making. To date, three plans have been completed: one outlining overarching principles for habitat protection, another for the Hawkesbury–Nepean river system, and a third plan covering an ecosystem type, seagrasses.

In 2003, the Murray-Darling Basin Ministerial Council approved a 10-year Native Fish Strategy in response to key threats to native fish populations in the basin. Since 2004, the Sustainable Rivers Audit has been using scientific indicators of health, including fish, macroinvertebrates and hydrology, to determine the status and trends of rivers in the Murray–Darling Basin.

In addition, more comprehensive, targeted surveys are conducted every three to four years for threatened freshwater fish species in NSW. For example, surveys are carried out for the Oxleyan pygmy perch in coastal wallum waterbodies on the NSW North Coast. Surveys are also conducted for Macquarie perch and Adams emerald dragonfly in the Hawkesbury–Nepean area.

The statewide natural resource management (NRM) targets relevant to this theme are 'By 2015 there is an increase in the number of sustainable populations of a range of native fauna species' and 'By 2015 there is an increase in the recovery of threatened species, populations and ecological communities'. There is a need for further data on a statewide basis to provide a full picture of progress toward the targets.

Future directions

New and innovative reforms and techniques are being introduced to enhance the conservation of biodiversity but it is still too early to assess their effectiveness in addressing issues that are pervasive and long-standing. In many cases significant trends will only become clear over a longer time frame, and it will require sustained commitment and perseverance to achieve results.

There has been a fundamental shift in focus from recovering individual threatened species – an approach which is largely reactive – to more pro-actively addressing the threats and drivers of biodiversity decline.

In conjunction, a greater emphasis is now being placed on endangered ecological communities rather than individual threatened species. This focus on species assemblages and threatening processes will maximise the benefits for all species, not only those that are listed as threatened.

The threat abatement plans that have already been developed establish a model for the future management of threatening processes. The Priorities Action Statements will establish priorities and provide overall guidance about where effort should be directed, while the monitoring of threat abatement plans will enable programs to be refined.

An expansion of the fish habitat protection process is desirable to ensure that all species are covered.

New models should be developed for government, stakeholders and the community to work together to advance the protection of aquatic species and restoration of habitats.

Monitoring of aquatic species diversity presents substantial challenges and there is little data available to assess the status of species. A targeted program that surveys species on an ongoing basis is urgently needed to support future monitoring and reporting requirements for SoE and the NRM Program, and to better target those species in real need of protection.

Knowledge of poorly understood groups, such as invertebrates and algae, should be enhanced to better inform conservation processes and assessments.