Risk assessment of Record Brook interbasin water transfer scheme to the aquatic fauna of the Donnelly and Warren Rivers
de Graaf, M., Morgan, D.L., Beatty, S.J. and Hugh, C.W. (2009) Risk assessment of Record Brook interbasin water transfer scheme to the aquatic fauna of the Donnelly and Warren Rivers. Western Australia. Dept. of Fisheries, Western Australia.
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This report describes the fishes and freshwater crayfishes of the Donnelly and Warren River catchments and provides a risk assessment to these fauna of the proposed extraction of water from Record Brook (tributary of the Donnelly River) and subsequent transfer to Scabby Gully Dam (Warren River catchment). The proposed location of the structure in Record Brook is at the gauging station ~1 km upstream from the confluence with the Donnelly River. The project aims to divert peak flows in the winter and spring flow period, transferring around 500 ML each year. The size and shape of the interception structure is yet to be determined, but are likely to incorporate a concrete weir < 5m high and a reservoir.
A total of six sites in Record Brook, Donnelly River and Scabby Gully Dam were sampled and these data were collated with additional historical information on the aquatic fauna of both catchments. An overview of fishes and freshwater crayfishes in the Donnelly River is summarised in Morgan & Beatty (2006), the authors recorded a high diversity of native freshwater species [Salamanderfish, Western Minnow, Black-stripe Minnow, Western Mud Minnow, Nightfish, Western Pygmy Perch, Balston’s Pygmy Perch, Freshwater Cobbler, (metamorphosed) ammocoetes of the Pouched Lamprey, Marron, (Restricted) Gilgie, Koonac, Freshwater Shrimp] as well as several estuarine [Western Hardyhead, Blue-spot Goby, South-west Goby] and non-native species [Mosquitofish, Redfin Perch, Rainbow Trout and Brown Trout]. The Donnelly River system is one of only two in south-western Australia that houses all of the endemic fishes of the region. The fauna of Record Brook contrasted that within the main channel sites of the Donnelly River. Within Record Brook, the fauna was dominated by the Pouched Lamprey, Koonac and Rainbow Trout, with the occasional Marron, Western Minnow and Western Pygmy Perch recorded. Within the Donnelly River main channel sites, the captures included Nightfish, Blue-spot Gobies, the Restricted Gilgie, Freshwater Shrimp and introduced Eastern Mosquitofish.The ichthyofauna of the Warren River consists of 14 fish species and is similar to the Donnelly River with the notable absence of Balston’s Pygmy Perch and Salamanderfish. However, in Scabby Gully dam only Marron and Redfin Perch were observed.
The risks of transfer of parasites and disease, feral/native fish or crayfish from Record Brook to Scabby Gully Dam are low. Threats to fish and freshwater crayfish in Record Brook include changes to water quality (altered flow, altered habitat and/or changes in temperature, oxygen, salinity) and requires ongoing monitoring should the project be implemented. The highest threat to fish and freshwater fish would be the barrier to fish movement by construction of the proposed dam. The construction of a fishway at the proposed dam would reduce some of the negative impacts to fish migration but would also require ongoing monitoring. No specially protected fish and/or crayfish species have been recorded in Record Brook. However, Record Brook acts as an important nursery area for the Pouched Lamprey and this species is listed as a Priority Species (Priority 1) by the Department of Environment and Conservation. The contents of this report are intended to inform of future management options and do not constitute, or replace any assessment or approval processes that may be required in accordance with the Environmental Protection Act 1986 and/or Environmental Protection and Biodiversity Conservation Act 1999.
|Murdoch Affiliation:||Centre for Fish and Fisheries Research|
|Series Name:||Fisheries Research. Contract Report No. 20|
|Publisher:||Western Australia. Dept. of Fisheries|
|Copyright:||2009 Western Australia. Dept. of Fisheries|
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