THE DONNELLY RIVER CATCHMENT: AN INTRODUCTION fishes inhabiting the Donnelly IMPORTANT REFUGE FOR ALL OF SOUTH-WESTERN River and the adjacent lakes were The freshwater fish assemblage AUSTRALIA'S ENDEMIC FRESHWATER FISHES AND documented by Morgan et al. THE POUCHED LAMPREY (GEOTRIA AUSTRALIS) of the south-west of Western (1998), and include data from the Australia (otherwise known as collections in the Western the Southwest Coast Drainage Australian Museum and from Division) has the highest those made by Christensen (1982) By DAVID L. MORGAN proportion (80%) of endemic and from Jaensch (1992) in Lakes Centre for Fish & Fisheries Research, Murdoch University, South St fishes in the country (Morgan et Jasper, Wilson and Smith. Murdoch, W A 6150. email: [email protected] al. 1998). Of the 10 native fresh­ Hodgkin and Clarke (1989) water fishes that are naturally and STEPHEN]. BEATTY provided a list of the fish species found within the south-west, found within the Donnelly Centre for Fish & Fisheries Research, Murdoch University, South St eight are found nowhere else. Murdoch, W A 6150. email: [email protected] River Estuary and also included The catchment of the Donnelly information on the catchment River is comparatively small, characteristics and physical covering an area of approxi­ features. Hoddell (2003) ex­ 2 ABSTRACT mately 1600 km , with the head­ amined the phylogeny (i.e. waters arising -60 km inland evolutionary relationships) of The fish fauna of the Donnelly River is described from historical published and unpublished data and from before flowing south-west where the Western Hardyhead captures during 2006. The Donnelly River catchment is one it discharges into the Southern (Leptatherina wallacei) and the of only two river systems that contain all of south-western Ocean (Hodgkin and Clarke 1989, Swan River Goby (Pseudogobius Australia's eight endemic freshwater fish species. The high Figure 1). Situated in the high alarum) in the lower estuary and diversity of fishes in the Donnelly River catchment, rainfall belt in the south-western Lake jasper and compared these including Lake jasper, Lake Wilson and Lake Smith, is likely corner of Western Australia, the to populations elsewhere in to be due to the heterogeneity of aquatic habitats in the catchment is largely uncleared south-western Australia. system. For example, species such as the Salamanderfish and (80-90%) (Hodgkin and Clarke Since the mid 1970s, a great deal Black-stripe Minnow are restricted to ephemeral pools and 1989, Pen 1999). Although there floodplain environments on Scott Rd and around Lake of research has been conducted Smith. Lake Smith is also the only known location within are -20 river systems that are into biological aspects of the the catchment of the rare Balston's Pygmy Perch and, larger than the Donnelly River Pouched Lamprey (Geotria together with Lake Wilson, is the only known habitat in in south-western Australia, it is australis) with much of the work the catchment of the large Freshwater Cobbler. The sixth in terms of mean annual (almost 100 scientific publi­ Western Minnow, Western Pygmy Perch and Nightfish were discharge (310000 ML). Within cations) involving lampreys from relatively common and widespread through the catchment; the Donnelly River catchment the Donnelly River; sites of cap­ occurring in most habitat types. The rare Western Mud are the near pristine wetlands of ture of adults and ammocoetes Minnow is restricted to headwater streams and is very Lake Jasper, Lake Wilson and (larvae) being presented in uncommon in the system, in part possibly due to predation Lake Smith. Parts of the lower Morgan et al. (1998). The Donnelly by exotic species. It is also one of the few systems that Donnelly River, Barlee Brook provide extensive habitats for the adult and larval stages of River is also regularly stocked the Pouched Lamprey. Three introduced fishes are known and much of Lake Jasper are of with Rainbow Trout from the Donnelly River, the Eastern Mosquitofish, Redfin important cultural and archaeo­ (Oncorhynchus mykiss) by the Perch and Rainbow Trout, the latter being the most logical significance and many of Department of Fisheries Western widespread; presumably as a consequence of the long term these sites are Registered Australia and limited infor­ stocking of the species into the catchment. Despite the Aboriginal Heritage Sites (Dortch mation on their diets are presence of these introduced species, the Donnelly River and Godfrey 1990, Goode 2003, presented in Morgan et al. (2004). should be considered of high conservation importance due Goode and Irvine 2006). to its south-western endemic fish populations. By collating relevant infor­ The distributions of fresh water mation in the above studies and Ii2 113 through additional sampling for Donnelly River. Utilising GPS co­ Sampling that was undertaken Pygmy Perch (Edelia vittata), fishes in the lower Donnelly ordinates and species occurrences during June 2006 included four Balston's Pygmy Perch River, this study aims to provide in Christensen (1982) (11 sites), sites within the estuary (tidal (Nannatherina balstoni) and the an overview of the fishes in the Jaensch (1992) (three sites), Morgan influence) and one site on Carey Nightfish (Bostockia porosa). Donnelly River and thus deter­ et al. (1998) (24 sites) and Hoddell Brook (Figure 1). Sampling The Salamanderfish is seldom mine its conservation signifi­ (2003) (three sites), with additional methods included monofilament found in the main channel, or cance in terms of the highly sampling of five sites during June gill nets, fine mesh (3 mm) seine even a major tributary, of any endemic fish fauna of the region. 2006, we generated a series of nets, and both boat deployed river system and the Donnelly is species maps using Maplnfo (240v) and backpack (12v) no exception. Within the METHODOLOGY (Mapinfo Corporation 1998) (see electrofisher. At the time of Donnelly catchment the Sala­ Figure 1). Information regarding sampling the river mouth was manderfish has been captured FISH DISTRIBUTIONS IN THE species in the estuary was collated open and the river was tidally DONNELLY RIVER from: the swamps surrounding from Hodgkin and Clarke (1989), influenced to at least Boat Lake Smith, in pools along Scott A number of studies provide Hoddell (2003), Brearley (2005) and Landing Road. Rd and on a large flat on information regarding specific from samples obtained during Pneumonia Rd (Figure 2). Within aspects of the fishes of the June 2006 (this study). RESULTS the Donnelly catchment, the Freshwater Cobbler is only In the following synopsis of the known from Lake Smith and fish fauna of the Donnelly River, Lake Wilson (Figure 3) (Jaensch we have grouped species into a 1992, Morgan et al. 1998). The number of conventionally used Western Minnow is widespread life history categories, i.e. species throughout the Donnelly River have been grouped if they are and is also very abundant in strictly freshwater, estuarine or Lakes Jasper, Wilson and Smith whether they are introduced (Figure 4). However, the Western fishes. A further category has Mud Minnow and Black-stripe been included to account for the Minnow were far more restricted; 1111 Thosstudy BARLEE BROOK anadromous Pouched Lamprey, the former being recorded at which belongs to a primitive • Morgan, Gdl & Potter (1 998) only three localities by group of fishes known as the Christensen (1982) (Figure 5), and A Hoddell (2003) 0 0 h DONNELLY RIVER Agnatha. the latter in a number of pools/ + Jaensch (1992) floodwaters along Scott Road "if Hodgkin & Clarke (1989) NATIVE FRESHWATER FISHES (Figure 6). The Western Pygmy 0 Chnstensen (1982) The endemic freshwater fishes Perch is widespread and relative­ that are currently known to ly common in a number of habi­ occur in the Donnelly River tats throughout the Donnelly LAKE JASPER~ catchment include the River catchment (Figure 7). It is Salamanderfish (Lepidogalaxias particularly abundant in Lake salamandroides}, the Freshwater Smith and Lake Wilson. Balston's SOUTHERN OCEAN Cobbler (Tandanus bostocki), the Pygmy Perch is extremely rare, Western Minnow (Galaxias and within the Donnelly River occidental!s), the Black-stripe catchment is only known from Minnow (Galaxiella nigrostriata), Lake Smith, with one individual Figure 1. Sites sampled for fish in June 2006 and during relevant past studies; each of which was used to provide species distributions throughout the the Western Mud Minnow found in Fly Brook (Figure 8) catchment. (Galaxiella munda), the Western (Morgan et al. 1998). The 114 115 WESTERN AUSTRALIA e Morgan, Gill & Potter (1998) BARLEE BROOK BARLEE BROOK 8 Morgan Gill & Potter (1998) • Jaensch (1992) 0 Chrislensen(19B2) ( CAREY BROOK LAKE JASPER~ LAKE JASPER~ SOUTHERN OCEAN SOUTHERN OCEAN Figure 4. Capture sites of the Western Minnow within the Donnelly River Figure 2. Capture sites of the Salamanderfish within the Donnelly River catchment. catchment. WESTERN AUSTRAUA WESTERN AUSTRAUA BARLEE BROOK BARLEE BROOK + Jaensch {1992) ( CAREY BROOK LAKE JASPER~ LAKE JASPER~ SOUTHERN OCEAN SOUTHERN OCEAN Figure 5. Capture sites of the Western Mud Minnow within the Donnelly River Figure 3. Capture sites of Freshwater Cobbler within the Donnelly River catchment. catchment. 117 116 WESTERN WESTERN AUSTRALIA AUSTRALIA 1 BARLEE BROOK BARLEE BROOK II_ DONNELLY RIVER ( ( CAREY BROOK CAREY BROOK LAKE JASPER~ LAKE JASPER~ SOUTHERN OCEAN SOUTHERN OCEAN Figure 6. Capture sites of the Black-stripe Minnow within the Donnelly River Figure 8. Capture sites of the Balston's Pygmy Perch within the Donnelly River catchment. catchment. WESTERN AUSTRALIA WESTERN AUSmAUA IJ This study 8 Morgan Gill & Potter (1998) BARLEE BROOK e Morgan, GUI & Pottar(199B) + Jaensch (1992) Jaansch (1992) + D 0 Christensen {1982) D Christensen (1982) LAKE JASPER~ LAKE JASPER~ SOUTHERN OCEAN SOUTHERN OCEAN Figure 7. Capture sites of the Western Pygmy Perch within the Donnelly River catchment. Figure 9. Capture sites of the Nightfish within the Donnelly River catchment. 118 119 Nightfish is found throughout head), South West Goby and Blue the catchment including in the Spot or Swan River Goby.