Welcome to the second edition of Freshwater Guardian, hot on the heels of our exciting first edition in spring!

Our new and informative newsletter aims to keep you up to date with our work and the research being conducted in Western Australia’s unique and beautiful freshwater ecosystems.

This summer edition includes articles about the upcoming marron season, the role of the Department of Fisheries in keeping our State’s waters free of pests and diseases, an activity that prevented the spread of a feral fish species and where to find information about what’s in your local lake.

Share this newsletter with your colleagues and friends, and please email any comments and suggestions about articles to us at freshwater.guardian@fish.wa.gov.au

Uluru is to Australia what the marron is to fishers in Western Australia – iconic. Marron, which are unique to WA, have been eaten by Indigenous Australians since time immemorial.

Marron is a freshwater crayfish endemic between Harvey and Albany.

The marron fishery is purely for recreational fishers and anyone who buys a marron fishing licence can capture these delicacies during the four-week marron season from 12 noon, 8 January to 12 noon, 5 February annually. Licence fees contribute to the management of the fishery.

Each year before the marron season, the Department carries out a stock assessment to ensure marron numbers are sufficient and stocks are sustainable. We monitor size and abundance at major marron fishing locations in rivers and dams throughout WA’s south-west.

After the season finishes, we conduct a survey of participants to gather information on catch and effort (how much time was spent fishing for marron).

The two survey results are reviewed together annually and used to inform future management decisions. This work is a considerable investment in time, money and resources, but essential to the continued sustainability of the fishery, particularly in the face of changing rainfall patterns. With continued commitment to the management of this fishery, this icon will persist for as long as Uluru.

Aquatic biosecurity is all about protecting the natural environment, the economy, human health and social amenity from problems associated with aquatic pests and diseases.

The key focus is on prevention because once a new pest or disease is introduced it is not only costly to manage but, unless detected early, usually impossible to eradicate.

In WA, we are the State Government lead agency for aquatic biosecurity, helping to keep our fisheries and aquatic environments free of the world’s most severe pests and diseases, and there are many fish species and diseases not native to WA that we need to keep out of our waters. Nationally, the Australian Government’s Department of Agriculture and its quarantine service also play a critical role in preventing many pests and diseases from entering Australia. 

We can all play our part in reducing the spread of aquatic pests and diseases. One of the main risks in WA is the inadvertent introduction of new pests and diseases by the general public, for example,when people release ornamental fish by emptying aquarium tanks into the natural environment. This can result in the establishment and spread of feral fish and diseases.

Here are some ways you can help:

• Never dump fish or aquarium contents into toilets, in or near waterways, into drains or the ocean.
• Humanely dispose of unwanted, sick or diseased fish.
• Don’t import, keep, breed or release noxious fish species.

For further information, please see our Don’t dump that fish brochure.

Perth and its surrounds are part of the Swan Coastal Catchment, which is drained by the beautiful Swan River and its tributaries. Unfortunately, in recent years, freshwater pest fish have become established within it. Once a pest fish makes it into a river catchment it’s likely, over time, to ‘put its tail up’ and stay.

The pearl cichlid, a hardy South American species sold in pet stores, is one such fish. It was first detected in Bennett Brook, near Guildford, in 2006. After the Department and other organisations identified that it posed a significant risk an attempt was made to eradicate it. However, it survived and has since spread rapidly in the Swan Coastal Catchment.

Containing it within this river system became key to management, so the discovery of an artificial channel, the Birrega Drain, that linked the Swan Coastal Catchment to the neighbouring Peel-Harvey Catchment caused concern. The Department of Water, Serpentine Jarrahdale Shire, Water Corporation and the land owner where the drain was located, all worked together to block this connection near the Wungong Brook junction.

While pearl cichlids are considered a freshwater fish, they can survive in water as saline as the ocean. If they were to establish in the Peel-Harvey Catchment, they would place native freshwater and marine species under threat.

The Biodiversity and Biosecurity freshwater section has a Statewide responsibility to ensure the health of our native freshwater fish species, many of which are unique to Western Australia, like the critically endangered trout minnow (left).

In 2009, the State Natural Resource Management (NRM) office funded the WA Native Fish Strategy. Our role in this project was to compile information on the distribution of native and feral fish populations. Outcomes included the development of the Freshwater Fish Distribution database and Freshwater Fish Distribution in WA website, which contain distribution information on native and introduced freshwater fish and invertebrate species in WA.

The information on the database, used to help guide management decisions, is being collected by government departments, universities, research agencies and students. The website makes much of this data available to the public, increasing awareness of WA’s freshwater diversity.

Previously, there has not been a single resource available for tracking the distribution of WA native and introduced freshwater fish species. It is a valuable tool in establishing priorities for our work. It also shows you what's in your local lake!

The database has grown rapidly and we are currently working on upgrades with Murdoch University. If you have any suggestions on how to improve the website, please let us know.