MURDOCH RESEARCH REPOSITORY This is the author’s final version of the work, as accepted for publication following peer review but without the publisher’s layout or pagination. The definitive version is available at http://dx.doi.org/10.1111/jfb.12121 Tweedley, J.R., Bird, D.J., Potter, I.C., Gill, H.S., Miller, P.J., O'Donovan, G. and Tjakrawidjaja, A.H. (2013) Species compositions and ecology of the riverine ichthyofaunas in two Sulawesian islands in the biodiversity hotspot of Wallacea. Journal of Fish Biology, 82 (6). pp. 1916-1950. http://researchrepository.murdoch.edu.au/15914/ Copyright: © 2013 The Authors. It is posted here for your personal use. No further distribution is permitted. Journal of Fish Biology Species compositions and ecology of the riverine ichthyofaunas on two Sulawesian islands in the biodiversity hotspot of Wallacea --Manuscript Draft-- Manuscript Number: Full Title: Species compositions and ecology of the riverine ichthyofaunas on two Sulawesian islands in the biodiversity hotspot of Wallacea Short Title: Freshwater fish ecology in Sulawesi Article Type: Regular paper Keywords: adaptive radiation; ecology; endemic and native; riverine and lacustrine fish; Sulawesi; Wallacea Corresponding Author: James Richard Tweedley, BSc (Hons), MRes, Ph.D. Murdoch University Perth, Western Australia AUSTRALIA Corresponding Author Secondary Information: Corresponding Author's Institution: Murdoch University Corresponding Author's Secondary Institution: First Author: James Richard Tweedley, BSc (Hons), MRes, Ph.D. First Author Secondary Information: Order of Authors: James Richard Tweedley, BSc (Hons), MRes, Ph.D. David J Bird, Ph.D. Ian C Potter, Ph.D. Howard S Gill, Ph.D. Peter J Miller, Ph.D. Grace O'Donovan, Ph.D. Agus H Tjakrawidjaja, Ph.D. Order of Authors Secondary Information: Abstract: This account of the riverine ichthyofaunas of the islands of Buton and Kabaena, off south-eastern mainland Sulawesi, represents the first detailed quantitative checklist and ecological study of the riverine fish faunas in the biological hotspot of Wallacea. The results are based on analysing samples collected by electrofishing at a wide range of sites in July to September of 2001 and 2002. While the fauna was diverse, with the 2179 fish caught comprising 64 species and representing as many as 43 genera and 22 families, the catches were dominated by the Gobiidae (26 species and 25% by numbers), Eleotridae (7 species and 27% by numbers), Zenarchopteridae (3 species and 22% by numbers) and Anguillidae (2 species and 12% by numbers). The most abundant species were the eleotrids Eleotris aff. fusca-melanosoma and Ophieleotris aff. aporos, the anguillid Anguilla celebesensis, the zenarchopterids Nomorhamphus sp. and Nomorhamphus ebrardtii, and the gobiids Sicyopterus sp. and Glossogobius aff. celebius-kokius. The introduced catfish Clarias batrachus was moderately abundant at a few sites. Cluster analysis, allied with the SIMPROF routine, identified seven discrete groups, which represented samples from sites entirely or predominantly on either Buton (five clusters) or Kabaena (two clusters). Species composition was related to geographical location, distance from river mouth, % contribution of sand and silt, altitude and water temperature. The samples from the two islands contained only one species definitively endemic to Sulawesi, i.e. Nomorhamphus ebrardtii, and another presumably so, i.e. Nomorhamphus sp., contrasting starkly with the 57 fish species that are endemic to Sulawesi and most notably its large central and deep lake Powered by Editorial Manager® and Preprint Manager® from Aries Systems Corporation systems on the mainland. This accounts for the ichthyofaunas of these two islands, as well as those of rivers in northern mainland Sulawesi and Flores, being more similar to each other than to those of the central mainland lake systems. This implies that the major adaptive radiation of freshwater fishes in Sulawesi occurred in those lacustrine environments rather than in rivers. Powered by Editorial Manager® and Preprint Manager® from Aries Systems Corporation *Manuscript 1 Species compositions and ecology of the riverine 2 ichthyofaunas on two Sulawesian islands in the biodiversity 3 hotspot of Wallacea 4 5 J.R. TWEEDLEY*†, D.J. BIRD‡, I.C. POTTER*, H.S. GILL*, P.J. MILLER§, 6 G. O’DONOVAN‡ AND A.H. TJAKRAWIDJAJAǁ 7 8 *Centre for Fish and Fisheries Research, School of Biological Sciences and 9 Biotechnology, Murdoch University, 90 South Street, Perth, Western Australia 6150, 10 Australia 11 ‡Department of Applied Sciences, University of the West of England, Bristol, 12 BS16 1QY, United Kingdom 13 §School of Biological Sciences, University of Bristol, Bristol, BS8 1UG, United 14 Kingdom 15 ǁ Zoology Division, Research Centre for Biology, Indonesian Institute of Sciences (LIPI), 16 Cibinong, Bogor, 16911, Indonesia 17 18 †Author to whom correspondence should be addressed, 19 Tel: +61 8 9239 8808; Email: [email protected] 20 21 22 Running headline: Freshwater fish ecology in Sulawesi 1 23 ABSTRACT 24 This account of the riverine ichthyofaunas of the islands of Buton and Kabaena, off south- 25 eastern mainland Sulawesi, represents the first detailed quantitative checklist and ecological 26 study of the riverine fish faunas in the biological hotspot of Wallacea. The results are based 27 on analysing samples collected by electrofishing at a wide range of sites in July to September 28 of 2001 and 2002. While the fauna was diverse, with the 2179 fish caught comprising 64 29 species and representing as many as 43 genera and 22 families, the catches were dominated 30 by the Gobiidae (26 species and 25% by numbers), Eleotridae (7 species and 27% by 31 numbers), Zenarchopteridae (3 species and 22% by numbers) and Anguillidae (2 species and 32 12% by numbers). The most abundant species were the eleotrids Eleotris aff. fusca- 33 melanosoma and Ophieleotris aff. aporos, the anguillid Anguilla celebesensis, the 34 zenarchopterids Nomorhamphus sp. and Nomorhamphus ebrardtii, and the gobiids 35 Sicyopterus sp. and Glossogobius aff. celebius-kokius. The introduced catfish Clarias 36 batrachus was moderately abundant at a few sites. Cluster analysis, allied with the SIMPROF 37 routine, identified seven discrete groups, which represented samples from sites entirely or 38 predominantly on either Buton (five clusters) or Kabaena (two clusters). Species composition 39 was related to geographical location, distance from river mouth, % contribution of sand and 40 silt, altitude and water temperature. The samples from the two islands contained only one 41 species definitively endemic to Sulawesi, i.e. Nomorhamphus ebrardtii, and another 42 presumably so, i.e. Nomorhamphus sp., contrasting starkly with the 57 fish species that are 43 endemic to Sulawesi and most notably its large central and deep lake systems on the 44 mainland. This accounts for the ichthyofaunas of these two islands, as well as those of rivers 45 in northern mainland Sulawesi and Flores, being more similar to each other than to those of 46 the central mainland lake systems. This implies that the major adaptive radiation of 47 freshwater fishes in Sulawesi occurred in those lacustrine environments rather than in rivers. 48 49 Key words: Sulawesi; Wallacea; riverine and lacustrine fish; endemic and native; ecology; 50 adaptive radiation 51 2 52 INTRODUCTION 53 Wallacea, which comprises a group of islands between Asia and Australasia, is one of 54 25 biodiversity hotspots identified by Myers et al. (2000) on the basis that it contained very 55 high concentrations of endemic species and was undergoing exceptional loss of habitat. The 56 western and eastern boundaries of Wallacea are essentially defined by Wallace’s line and 57 Lydekker’s line, respectively (Michaux, 2010; Fig. 1a). The islands of Wallacea, among 58 which mainland Sulawesi is the largest, thus lie between the land masses on the Sunda Shelf, 59 comprising the Malay Peninsula, Sumatra, Borneo and Java to the west, and those of the 60 Sahul Shelf, including Australia and New Guinea, to the south and east (Fig. 1). 61 The ‘barrier’ produced by the deep ocean trenches that separate Wallacea from the 62 land masses on the Sunda and Sahul continental shelves help account for the high level of 63 endemism in the fauna of Wallacea (Wallace, 1863; Myers et al., 2000). A collation of the 64 species recorded in Wallacea emphasises the extent of this remarkable endemicity, with 65 nearly 70% of its amphibians, nearly 60% of its mammals and over 40% of its reptiles and 66 birds endemic to this region (Conservation International, 2012). Although the level of 67 endemicity among freshwater fishes (20-25%) is not as great, it still represents a substantial 68 number of species. Furthermore, the endemicity of freshwater fishes has been known, for 69 some time, to be particularly high on mainland Sulawesi (Kottelat et al., 1993). Indeed, 70 Parenti (2011) has recently estimated that the freshwater ichthyofauna of Sulawesi contains 71 as many as 56 endemic species, to which a recently-described species is now added 72 (Huylebrouck et al., 2012). Among these 57 species, 45 are atherinomorphs (represented by 73 the orders Atheriniformes and Belonifomes), with the remainder comprising perciforms, 74 i.e. gobioids and a single terapontid species. Most of these species were described, however, 75 from the large central tectonic lake systems (Kottelat, 1990a,b,c, 1991; Herder et al., 2006b). 3 76 Several authors have emphasised that