Goldfish control in the Vasse River: summary of the 2008 programme

This report summarises the results of the 2008 round of the feral Goldfish control in the lower Vasse River and comparisons made with previous control efforts since 2004

Ascending the Avon: fishes of the Northam Pool, and the Swan-Avon catchment

The fish fauna in the vicinity of the Northam Pool Weir was sampled seasonally between winter 2008 and autumn 2009. The results indicate that the fish community was characterised by species that are halotolerant including two estuarine species, the Western Hardyhead and Swan River Goby that are likely to have undergone large upstream expansions in the Swan‐Avon catchment due to secondary salinisation. However, two freshwater endemic species, the Western Minnow and Nightfish were also recorded in the vicinity of the weir. These, and other freshwater endemic species, have undergone large range reductions in this catchment as a result of salinisation. The study found evidence that the weir may be impeding the upstream movements of native fishes as found elsewhere in south‐western Australia and that construction of a well‐designed fishway would enhance population connectivity and increase their sustainability. It is recommended that additional sampling occurs during the major spawning periods of the freshwater species immediately below the weir to determine precisely when a future fishway would need to operate to allow maximum usage by resident native species. It is also recommended that fresh refuge habitats for freshwater fishes be identified to allow effective management measures to be implemented in those systems to halt their decline and reduce the risk of complete loss of these species from the Swan‐Avon catchment

Distribution of the spotted minnow (Galaxias maculatus (Jenyns, 1842)) (Teleostei: Galaxiidae) in Western Australia including range extensions and sympatric species

Galaxias maculatus was captured from a number of rivers outside its previously known range. In Western Australia, it was formerly only known from rivers and lakes between the Goodga River (Two People's Bay, 30 km east of Albany) and the Dailey River (50 km east of Esperance), with additional records from the Boat Harbour Lakes (Kent River). An intensive survey of the inland fishes in rivers and lakes along the south coast of Western Australia has extended its distribution east by 50 km (Thomas River), west by approximately 40 km (Walpole River) and north by 400 km (Harvey River). The Western Australian Museum also has a specimen from the Canning River, a further 100 km north. Field salinity tolerance of G maculatus was high, with fish found alive in 81 mScm 1 (-45 ppt). The freshwater piscifauna east of, and including, the Pallinup River is depauperate, with G. maculatusbeing the only freshwater species present. All sympatric teleosts are tolerant of salinity and, with the exception of the introduced Gambusia holbrooki, are estuarine, including Pseudogobius olorum, Leptatherina wallacei and Acanthopagrus butcheri

History of cichlids in Western Australian aquatic ecosystems

Three species of the family Cichlidae have been reported from Western Australian waterways, including Tilapia zillii, Oreochromis mossambicus and Geophagus brasiliensis. While T. zillii was first found in 1975 and was successfully eradicated, O. mossambicus was first recorded in natural waterways of Western Australia in 1981, and has since spread to a further three river systems through either human-assisted dispersal or from flooding events. Recent research assessing the distribution and impact of the species in Western Australia suggests that O. mossambicus poses a serious threat to the unique aquatic fauna of Western Australian inland waters, including estuaries. The entry of other cichlids into the State’s waterways, including G. brasiliensis, which was first discovered in 2006, has the potential to impact Western Australia’s unique aquatic fauna in both inland freshwaters and estuaries

Resurvey of historical collection sites for Balston’s Pygmy Perch in the South West Linkages Target Area

Balston’s Pygmy Perch (Nannatherina balstoni) is one of the rarest native freshwater fishes endemic to south-western Australia (Morgan et al. 2011, 2014). The species inhabits near-coastal lakes, wetlands and flowing streams, and was historically distributed between the Moore River (north of Perth) and the Angove River (east of Albany) (Morgan et al. 2011, 2014). Numerous anthropogenic stressors including habitat destruction, pollution, river regulation, and water abstraction have resulted in an approximate 31% decline in the distribution, with the species apparently having been extirpated from the Swan Coastal Plain and a number of other systems across its range (Morgan et al. 2014). The contemporary distribution extends from the upper reaches of the Margaret River to the Angove River near Two Peoples Bay (Morgan & Beatty 2003; FFGFHU unpubl. data) (see Figure 1). Remnant populations are highly fragmented within this range (Morgan et al. 2014). In light of its typically low abundance and restricted distribution, N. balstoni has been formally recognised as Vulnerable to extinction under the Commonwealth Government’s Environment Protection and Biodiversity Conservation (EPBC) Act 1999 and is listed under Schedule 1 (“fauna that is rare or is likely to become extinct”) of the Western Australian Government’s Wildlife Conservation Act 1950. Accordingly, this fish is the flagship species of the current project entitled “Protecting threatened fishes in the South West Linkages Target Area”. A thorough review of the historical distribution of N. balstoni was conducted at the outset of this project and has now been published in the scientific literature (see Morgan et al. 2014). To complement this review, one of the project’s primary aims was to resurvey a number of historical collection sites in order to ground-truth the current status of resident N. balstoni populations. The results of this survey should provide valuable data for authorities in developing management and recovery strategies for the conservation of this threatened south-western Australian endemic

Marron, more than a meal. Harvey River restoration, Western Australia

The Southwestern Province has the highest proportion of endemic fishes and crayfishes on the continent, and is a globally recognosed endemic hospot. Over the last few decades, there has been a growing body of evidence that has suggested that the inland aquatic fauna of the Southwestern Province of Western Australia is declining. Much of this decline has been driven by large scale modification to habitat quality and quantity. The loss of suitable habitats through stream channelisation, river regulation, land clearing, flood abatement and the impact of introduced species, has resulted in large-scale losses of aquatic fauna. This, coupled with the increasing impact of climate change driven reductions in rainfall and subsequent run-off and aquifer recharge continue to challenge the aquatic fauna and necessitates adaptive management to help with their conservation. Since the turn of the Century, five of the region’s freshwater fish species, four freshwater crayfish species and the sole species of freshwater mussel have been listed as threatened under the Federal Government’s Environment and Biodiversity Conservation Act (EPBC Act 1999). Other species are variously listed under State legislation. Surprisingly, in 2013, the significant discovery of a previously undetected fish species was made, and since that time, several other species have been discovered in the region, but await formal description. The Marron (Cherax cainii) is recognised as a south-western Australian aquatic icon, not only for the important and unique recreational fishery that it supports, but also for its aquaculture potential and the sheer size to which it attains; while also being considered a delicacy and a biological indicator of ecosystem health. The Marron, More than a Meal Project aims to demonstrate how the restoration of drainage channels can lead to an improvement of the aquatic ecosystems

Narrow Line X-Ray Calibration Source for High Resolution Microcalorimeters

We are developing a narrow line calibration source for use with X-ray microcalorimeters. At energies below 300 electronvolts fluorescent lines are intrinsically broad, making calibration of high resolution detectors difficult. This source consists of a 405 nanometers (3 electronvolts) laser diode coupled to an optical fiber. The diode is pulsed to create approximately one hundred photons in a few microseconds. If the pulses are short compared to the rise time of the detector, they will be detected as single events with a total energy in the soft X-ray range. Poisson fluctuations in photon number per pulse create a comb of X-ray lines with 3 electronvolts spacing, so detectors with energy resolution better than 2 electronvolts are required to resolve the individual lines. Our currently unstabilized diode has a multimode width less than 1 nanometer, giving a 300 electronvolt event a Full width at half maximum (FWHM) less than 0.1 electronvolts. By varying the driving voltage, or pulse width, the source can produce a comb centered on a wide range of energies. The calibration events are produced at precisely known times. This allows continuous calibration of a flight mission without contaminating the observed spectrum and with minimal deadtime

Introduced freshwater fishes in a global endemic hotspot and implications of habitat and climatic change

Introductions of alien freshwater fish species into the Mediterranean-climatic South-west Coast Drainage Division of Australia have impacted a highly endemic (≈82%) yet depauperate (11 species) native freshwater fish fauna. This study updates the current known introduced freshwater fishes in Western Australia, assesses the historic rate of introductions and how habitat, water quality and climatic changes have facilitated those introductions. South-western Australia has undergone a ≈63% increase in alien freshwater fish introductions since 1970 (44% increase over the past decade) to 13 species; overtaking the number of native fishes. Aquarium species represent 80% of the latest introductions (46% of total number) and the majority (54%) of introduced fishes in the region are of sub-tropical or tropical origin. As found elsewhere, species with broad environmental tolerances and generalist diets are likely to continue to be the main colonizers in this region. We propose that past and future climatic and habitat changes in the Mediterranean-climatic south-west region will facilitate continued invasion of tropical and sub-tropical aquarium fishes and that strategic monitoring, control and public education programs are required to halt future introductions

How do Black Bream move through the fish gate on the Vasse Surge Barrier?

This study determined how Black Bream used the fish gate on the Vasse Surge Barrier by tagging them state of the art internal electronic tags. The tags, known as PIT tags, detected fish that passaged upstream and downstream through the fish gate over an 18 month period in 2017 and 2018. The local community helped us tag and release 322 Black Bream. The study revealed that movements through the fish gate were unrelated to spawning activity of this species and supported early work that the Vasse Estuary is not a key breeding site; instead they use the Deadwater to reproduce. Up until May 2018, Bream passaged through the fish gate 440 times (265 downstream and 175 upstream). Black Bream preferred to passage when the water velocity in the fish gate chute were lowest, which occurred when the water levels upstream and downstream of the surge barrier were relatively similar. When the dissolved oxygen upstream of the surge barrier was good, fewer fish passaged downstream to the Wonnerup Inlet although this was a relatively weak effect. However, the dissolved oxygen around the Vasse Suge Barrier during the current analysis period was relatively high compared to other years and therefore we anticipate that the effect of low dissolved oxygen on fish passage would be even stronger in those years. They also preferred to pass downstream through the fish gate during the evening, whereas upstream passages mostly occurred during the dawn and dusk periods. The findings greatly increase our understanding of the conditions that Black Bream require or prefer to use the fish gate on the Vasse Surge Barrier. However, as the PIT tags last for 20 years, additional data analysis is recommended to compare the factors influencing the passage of the species over multiple years of fish gate operation; including those years that experience poor oxygen levels. It is also recommended that additional fish PIT tagging occur, including other species, so that long-term fish passage through the structure may be further quantified

Quantification of stress transfer in a model cellulose nanocrystal/graphene bilayer using Raman spectroscopy

This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record The dataset associated with this article is located in ORE at: https://doi.org/10.24378/exe.1303Graphene and cellulose possess a multitude of unique and useful properties for applications in electronics, sensors and composites which has led to significant scientific interest over the past 5–10 years. Despite this interest, there has been no experimental work investigating the interface or stress transfer efficiency between these materials, which limits future developments in this field. With the aim of investigating this interface, we have created a model bilayer composite, consisting of a tunicate derived cellulose nanocrystal (T-CNC) film and a monolayer of graphene produced by chemical vapour deposition. Raman spectroscopy has been used to monitor the four-point bending of this model bilayer composite. Shifts in the position of Raman bands, unique for both the cellulose and graphene components of this model composite, are recorded. Using a novel analysis of these Raman band shifts, we have formed an expression which deconvolutes the total stress transfer efficiency of the model system. Using this deconvolution, a stress transfer efficiency of 66% has been derived at the cellulose/graphene interface. In addition, splitting of the graphene Raman G band has allowed calculation of the shear strain in the graphene, which is assumed to be equal to that at the cellulose-graphene interface. The individual T-CNCs in the reference samples showed location dependent preferential orientations. The film was found to be stiffer when the T-CNCs were oriented parallel to the loading axis. It was intended that the varying stiffness of the cellulose film could be used to analyse the effects of underlying film stiffness on stress transfer efficiency, but conclusions from this test were limited. The detailed interface analysis presented here will help to inform design in future cellulose/graphene devices.Engineering and Physical Sciences Research Council (EPSRC