Giant Freshwater Crayfish recovery project newsletter - Issue 2 | June 2021

ISSUE 2 | JUNE 2021

Giant Freshwater Crayfish Recovery Project

Welcome to the second newsletter about the Giant Freshwater Crayfish Recovery Project being undertaken by Cradle Coast Authority’s Natural Resource Management team.

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This project is supported by the Cradle Coast Authority, through funding from the Australian Government's National Landcare Program.

The Giant Freshwater Crayfish Astacopsis gouldi or the Giant Freshwater Crayfish is the largest freshwater crustacean in the world and is unique to northern Tasmania. It has been recorded from the Arthur-Pieman catchment in the north-west and in most of the northern rivers that flow into Bass Strait.

This species is slowgrowing and longlived, with females taking up to fourteen years before they can breed and males up to nine years. They can live up to sixty years.

A juvenile crayfish approximately 5 years old

Habitat ___________________ Habitat requirements for Giant Freshwater Crayfish vary depending on their age. Young c rayfish prefer shallow, fast-flowing streams with bed materials such as cobbles and boulders

that they use for shelter. Adults often move to slower-flowing reaches where they like undercut banks to burrow in, or logs and boulders to seek shelter under.

They prefer well-vegetated streams with clear water and even, cool temperatures. In addition to providing shelter, in-stream logs and dead wood are critical for providing food.

Vegetation along both banks of the waterway moderates temperature extremes and filters sediments from soil and effluent which would otherwise muddy the water and degrade crayfish habitat.

What is a Conservation Covenant? ___________________ Under the project, landholders in the priority areas may be eligible to develop a proposal for a conservation covenant to protect good quality Giant Freshwater Crayfish habitat, including surrounding nativevegetation. The covenant area needs to be a minimum of 10 ha toprovide long term viability of the area protected.

A conservation covenant is a voluntary agreement between the landholder and the state minister administering the Nature Conservation Act 2002. Conservation covenants aim to protect and enhance the natural, cultural and/or scientific values of the area of land under covenant. The covenant is attached to the land title, to provide long term protection to the area even if ownership changes.

Conservation covenants are part of Australia’s National Reserve System and provide the highest level of protection for private land conservation. Tasmania has more than 900 conservation covenants protecting 112,000 ha. Each covenant is tailored to suit the property and is developed with the landowners based on a natural values assessment and the management requirements. Conservation covenants provide landholders an opportunity to protect valuable Giant Freshwater Crayfish habitat on their land into the future.

Those who enter into a covenant under the project can also access funding for any project works needed as well as access stewardship payments up until June 2023.

The Giant Freshwater Crayfish The Giant Freshwater Crayfish Recovery Project started in October 2019 and continues until June 2023. It is working with agricultural landholders in targeted sections of rivers in the Cradle Coast area. The aim of the project is to protect known populations of Giant Freshwater Crayfish and improve the extent and quality of their habitat.

A stretch of good quality habitat of one kilometre has been suggested by crayfish expert Todd Walsh as the minimum length of stream habitat that can support a viable population of GFCs. As a result, one kilometre is used as the minimum length of high-quality remnant habitat that project sites must connect to.

One kilometre is also the minimum length of stream section that this project aims to work on, whether that is on one property or multiple.

We have now been working with agricultural landholders in the following six priority areas to develop projects:

To be considered for the project, potential habitat improvement areas must be at least one kilometre and have a link to existing good remnant native vegetation. This reduced the priority areas to fourteen.

Upper Leven River Part of the Flowerdale River and tributaries in the Lapoinya area Black River near Newhaven Rd Hook Creek and Detention River Roger River, Spinks Creek, Upper Duck River Lower Inglis River

Initial engagement activities were undertaken across these identified areas to gauge the level of landholder interest in participating in the project.

Initial baseline monitoring of the species, including trapping, measurement, tagging and returning crayfish to their site of capture has now been undertaken in all six of the priority areas, prior to starting any onground works.

To date (June 2021) ten landholders have entered into Funding Agreements to protect or rehabilitate 27.4 km of river corridors. With funding from the Australian Government’s National Landcare Program, the aim of the project is to rehabilitate at least 24 km of river bank in the priority areas, which results in both sides of the stream being restored or improving condition. Financial incentives have been provided to implement works and include: Riparian fencing to exclude stock and install off-stream water points.

Native vegetation establishment and weed control provide timber recruitment into the waterway.

Erosion control works to stabilise banks or beds of waterways.

Establishment and management of filter zones or buffer strips through fencing and re-vegetation.

Site monitoring.

Establish conservation covenants and manage areas of good remnant native vegetation for conservation.

Recovery Project Update A further eight landholders are in the process of developing projects for assessment and funding. Any landholders who are interested in pursuing a river project in the priority area, please do not hesitate to contact the Project Coordinator.

The focus of the project for the next twelve months will be working with individual landholders to implement the on-ground works or conservation programs identified in their funding agreements.

A short video on the Giant Freshwater Crayfish has been produced and is available on our website https://www.cradlecoast.com/cc a/natural-resource-management.

Willows are a major invasive weed in some of our priority reaches and impact nutrient levels, bank and bed erosion, can reduce flows and provide limited animal habitat.

A short video on the Giant Freshwater Crayfish has been produced and is available on our website

www.cradlecoast.com/ cca/natural-resourcemanagement

Field Tour _________________ A project Field Tour by bus was also held in March 2021 to look at two sites: one in the Upper Inglis that had previously been fenced and revegetated, and one of the current proposed project sites at Lapoinya.

Despite inclement weather, 36 participants turned up to hear tips on riparian management from both landholders and the Project CoOrdinator, information on the lifecycle of Giant Freshwater Crayfish and view live animals with technical expert Todd Walsh, and hear information on conservation covenants from Dr Helen Morgan of the Tasmanian Land Conservancy.

This Field Tour identified a demand for further information sessions and/or Field Days on this threatened species.

It is important with fencing to leave sufficient buffer widths from the top of the high bank to allow revegetation or natural regeneration and create filtered buffer strips for paddock runoff and provide bank stability against streambank erosion.

Baseline monitoring and what it involves Baseline monitoring has been undertaken in all six priority areas before any project works were implemented. This, combined with monitoring undertaken at the end of the project in 2023, will help identify any changes or improvements that may have occurred in each stretch of river over the life of the project.

Many of the proposed project works such as revegetation will take many years to get established and should provide longer term benefits such as reintroduction of timber into the river and moderating the impacts of heat waves. This will require longer term monitoring beyond the life of the project.

Baseline monitoring involved a number of activities. This included using baited nets to identify the presence or absence of adult crayfish, lifting and netting in small boulder or cobble sections to look for juveniles and riffle or rapids were chosen to undertake AUSRIVAS sampling.

AUSRIVAS is a national biomonitoring scheme that is used to assess the “biological health” of rivers. Traditionally water quality guidelines have focused on physical and chemical indicators of stream condition. AUSRIVAS uses aquatic macroinvertebrates (animals without backbones that can be seen with the naked eye such as mayfly, caddis fly, dragonfly larvae and shrimps) as biological indicators of river health.

Macroinvertebrates are widely used because they are generally

Using a kick net to undertake AUSRIVAS sampling in a riffle

abundant throughout the study area, easy to collect and identify, have relatively long life-cycles, and are sensitive to various changes in water and habitat quality.

As sensitive macroinvertebrates, such as large stoneflies, are not found in impacted waterways, a highly sophisticated and accurate indication of water quality is provided by the presence or absence of macroinvertebrate families.

The aquatic biota are a more meaningful measure of water quality because they integrate the preceding river conditions for weeks or months before their collection. AUSRIVAS sampling and interpretation was undertaken by an accredited expert in both spring and autumn and will be used to show long-term ecological change at sampling sites.

Sites at the upstream end of proposed project reaches and sites at the downstream end of proposed project reaches were chosen, where available.

Generally, one of these was a good remnant vegetation reference site. Because of the different habitat requirements of juvenile versus adult Giant Freshwater Crayfish, a number of sites along a reach might have been sampled. For example, juveniles prefer the faster flowing and shallower areas of the stream, whereas adults prefer well-shaded, flowing parts of the stream with deep pools, decaying logs and undercut banks.

The presence or absence of juveniles and adults was noted at each site. It is the densities of both adults and juveniles that vary in sites with poor habitat to those in near pristine conditions. Giant Freshwater Crayfish can be found in low numbers in many poorquality sites; however, the densities increase rapidly in sites with excellent habitat. Adults were measured, weighed, and tagged before being released back into the same spot they were trapped.

Sampling information was collected and is recorded in a state-wide database.

Future monitoring will involve trying to use in-stream microchip readers to monitor the movement of these tagged adults.

For landholders who are interested in getting involved in citizen science projects relating to macroinvertebrate sampling, John Gooderham of the Waterbug Company (www.thewaterbug.net) helps to organise annual water bug surveys. Contact John direct or through your local Landcare group.

Siltation - major threat

The lower reaches of the Inglis River with high levels of fine sediment after rainfall in June 2021

Siltation Any form of land clearing or habitat disturbance that results in increased siltation of waterways is of high risk to Giant Freshwater Crayfish. Siltation or sedimentation can affect their ability to breathe oxygen through the gills and affects the health of the crayfish, particularly during their juvenile stages.

topsoil is retained. riverbanks remain stable and there is no loss of productive land. there is no accumulation of sediment. water quality is improved or maintained as there are no nutrients and development of algae.

Siltation or sedimentation can come from bed or bank erosion within a waterway, from stock access and in–stream stock watering points, from dirt roads and farm crossings across creeks and gullies, exposed soil in or near drainage lines and from land clearing in the catchment.

Riparian land is amongst the most productive land in the catchment due to higher moisture content and deeper soils. It often offers more shade and shelter. However without adequate vegetation to hold it together, it can also be very vulnerable to erosion, loss of riverbanks and hence productive land, particularly in flood or high flow events.

The width of buffer strips required depends on: the size of the waterway and catchment. the size of the cross-sectional area of the waterway. quality and type of native vegetation present. the steepness of the riverbanks. where you are located on the waterway.

Buffer strips It is important to ensure that waterways have adequate vegetated buffer strips between farming areas or access tracks and infrastructure that will allow runoff to slow down and filter sediment and nutrients before it enters the river or creek.

When establishing vegetated buffer strips along waterways it is important to consider carefully the siting of off-stream watering points and the presence of shade for livestock in the paddock.

Troughed water is usually cleaner and more palatable to stock and clean water encourages higher consumption of dry matter.

Restricting stock from riparian areas through fencing also ensures: native vegetation is not destroyed or trampled and provides adequate shade and habitat for native animals.

For example, outside bends of rivers usually require wider buffers because that is where the velocity of the water is highest, particularly at the toe of the bank. If in doubt it is worth seeking technical advice on the issue.

Shade is important for stock health, particularly in summer, and sometimes riparian areas contain the only existing shade and shelter belts.

Crossings Any farm or access tracks need adequate drainage installed and drainage needs to flow out across undisturbed grassed or vegetated areas to conserve soil and retain nutrients. Waterway crossings need to avoid bends in the river and be located wherever possible on straight stretches of river. Where possible, select a site downstream of a bend rather than upstream.

Build your crossing straight across the waterway to avoid water concentrating in a small area. The design of your crossing will depend on the nature of the waterway, the level of investment you are interested in, and the nature of ongoing maintenance of the structure. Bridges require high initial investment but often cost less in long term maintenance. Provided they are designed and installed properly, they are most suitable for deep waterways or those prone to flooding.

On the other hand, gravel crossings or causeways need to be installed at bed level so as to have minimal impact on flow, erosion and habitat, but require much more maintenance and may not be accessible in all weathers. They are most suitable for waterways that flow infrequently or only experience low flows. Giant Freshwater Crayfish do not cope well with crossings or culverts and will often travel overland to avoid them. Culverts and pipes are also easily blocked particularly in waterways with high sediment or woody debris loads.

Our Agriculture team is currently working closely with farmers through our Protecting Our Productive Soils Project to develop a variety of techniques in both cropping and pasture systems to reduce the impact of soil erosion and avoid sedimentation of our waterways.

A particular focus is on biological methods that include establishing multi- species cover crops and pastures. These systems provide a diverse root assemblage that can quickly improve soil structure and stabilise bare soil. This process also provides mechanisms for capturing nitrogen from the atmosphere and reducing fertiliser inputs that can leach into waterways.

If you require further information on this project, please contact Ali Dugand on adugand@cradlecoast.com

Illegal fishing of Giant Freshwater Crayfish ___________________

Did you know...

For ease of fencing, it is easier to keep fence lines as straight as possible, while providing adequate buffer from the top of the stream bank. Build parallel to the likely direction of water. This also means less fence maintenance if the fence is constructed as far above the flood line as possible.

Other things to consider for riparian fencing include using plain wire in preference to mesh and avoid using droppers to limit debris build up, reinforce end assemblies, drive in posts and reduce the space between posts to strengthen the fence.

Poaching of crayfish, particularly larger breeding adults can lead to the loss of localised populations.

It is illegal to catch or kill any of the three species of Astacopsis in Tasmania.

Penalties of up to $105,000 and/or a year in prison are possible under Tasmanian Threatened Species legislation.

Under Inland Fisheries legislation, killing a Giant Freshwater Crayfish (or other Astacopsis species) is prohibited and can attract fines of up to $10,000.

When poaching sites are identified, Inland Fisheries officers will monitor sites and install camera monitoring points.

Members of the public and landholders are encouraged to report evidence of poaching of Giant Freshwater Crayfish via email to the Inland Fisheries Service at infish@ifs.tas.gov.au or call 0438 338 530 or Crime Stoppers on 1800 333 000.

Further information

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The Giant Freshwater Recovery Project is funded from the Australian Government’s National Landcare Program and is due for completion in June 2023.

If you require more information or wish to participate in the Giant Freshwater Crayfish Recovery Project, please contact Agriculture, Project Coordinator, Fiona Marshall on the following details: Phone: 03 6433 8433 Mobile: 0413 382 390 Email: fmarshall@cradlecoast.com

Website: www.cradlecoast.com