Fishes of the Nymboida, Mann and Orara Rivers of the Clarence River Drainage, New South Wales, Australia R.C. Cashner 1 , G.P. Hawkes 2 , D.F. Gartside 3 and E. Marsh-Matthews 4 'Department of Biological Sciences, University of New Orleans, New Orleans LA 70148, USA; department of Zoology, University of Melbourne, Parkville VIC 3052; 3 Centre for Coastal Management, Southern Cross University, Lismore NSW 2480; department of Zoology, University of Oklahoma, Norman OK 73019, USA. Cashner, R.C, Hawkes, G.P., Gartside, D.F. and Marsh-Matthews, E. (1999). Fishes of the Nymboida, Mann and Orara Rivers of the Clarence River Drainage, New South Wales, Australia. Proceedings of the Linnean Society of New South Wales 121, 89-100. A six-month survey of fishes in the Nymboida, Mann and Orara Rivers in northeast-ern NSW was conducted from March-August, 1991. Forty collections at 12 sites yielded over 7000 specimens, representing 20 species and 15 families. Marjorie's hardyhead (Craterocephalus marjoriae) accounted for 41% of the total specimens. Other numerical dominants included Douboulay's rainbowfish (Melanotaenia duboulayi) 16%, firetailed gud-geon (Hypseleotris galii) 11%, western carp gudgeon (H. klunzingeri) 8%, Australian smelt (Retropinna semoni) and eastern mosquitofish {Gambusia holbwoki) with 6% each. Although not numerous in the sampling, the endangered eastern freshwater cod (Maccullochella ikei) was recorded from the Nymboida River and the Australian bass (Macquaria novemaculeata) from the three rivers sampled. Sampling also revealed the exotic species rainbow trout (Oncorhynchus mykiss) in the upper reaches of the Nymboida River and the goldfish (Carassius auratus) in the three rivers. The pattern of distribution includes longitudinal zona-tion in the upper reaches, where only five species were recorded; three of which were restrict-ed to this region. This was followed by a rapid increase in species (11) beginning with the low gradient, less turbulent, middle section and then an addition of species (4) from the lower reaches of the system to the confluence with the Clarence River. Values for Jacard's (JI) and percent similarity (PSI) indices indicate the headwater fauna is highly dissimilar from the middle and lower reaches, while the three stations in the downstream section have similar faunas. The distribution pattern and results of the faunal similarity indices are corroborated by the results of detrended correspondence analysis (DCA). Manuscript received 15 June 1999, accepted for publication 17 November 1999. KEYWORDS: Clarence River drainage, freshwater fishes, instream distribution of fishes, Mann River, Nymboida River, Orara River. INTRODUCTION Australia's freshwater fish fauna has been characterized as depauperate when com-pared to the richness of other continental assemblages (Allen 1989). The most recent compilations include only between 180-196 species of fishes living in Australian fresh-water habitats (Merrick and Schmida 1984; Allen 1989), and the number of species com-pletely restricted to freshwater is probably 20-25% less than the number usually reported (Allen 1989). However, the inventory of Australian freshwater fishes is far from com-pleted. In the past several years populations of nominal species, such as Murray cod {Maccullochella peeli) (Rowland 1993), Macquarie perch {Macquaria australasica) (Dufty 1986), golden perch {Macquaria ambigua) (Musyl and Keenan 1992), blue-eyes {Pseudomugil signifer) (Ivantsoff et al. 1991), rainbowfish {Melanotaenia fluviatilis) Proc. Linn. Soc. n.s.w., 121. 1999
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