DIVERSITY, DISTRIBUTION AND ABUNDANCE OF FIJIAN FRESHWATER FISHES Plate 1. A new (as yet unnamed) freshwater fish species in the subfamily Sicydiinae from Fiji by David Boseto BSc Marine Science 2000 Postgraduate Diploma Marine Science 2001 A thesis submitted in partial fulfillment of the requirements for the degree of Master of Marine Science at the University of the South Pacific, Laucala Campus, Suva, Fiji. © April 2006 DECLARATION I, David Boseto certify that this thesis is my own work. Assistance and work by other people has been properly acknowledged and cited. 3/04/06 _____________________ ____________________ David BOSETO (Date) The research described in this thesis was performed under my supervision and to my knowledge is the sole work of Mr. David BOSETO 3/04/06 _______________________________ _____________________________ Professor William G.L. Aalbersberg (Date) You are encouraged to cite my thesis with proper citations and acknowledgements. ii ABSTRACT One of the poorly known aspects of the biodiversity of the Fijian Islands is the biodiversity of freshwater fauna. Data collected from this study were used to compile a checklist of Fijian freshwater and estuarine fish, determine the physical habitat factors influencing richness and abundance and identify biogeographic patterns including fish communities and assemblages found in different regions and habitat. In this survey, gill net, cast net, beach seine net, fine mesh net, pole seine net, hand net, spear gun, electro fisher machine, visual observation and hand gleaning were the techniques employed to document freshwater fish during the period of October 20th 2002 to October 10th 2004. Freshwater fish surveys were carried out in 66 sites in seven watersheds on the islands of Viti Levu, Vanua Levu and Taveuni. There are 40 sites in Viti Levu, 5 sites in Vanua Levu and 21 sites on Taveuni. The field surveys resulted in the collection of 2,615 fish specimens from 31 families and 76 species. Data from previous surveys and museum collections identified 151 species from 41 families. Taking into account overlap between field data and other collections, there are 89 known freshwater fish species from 26 families in Fiji. Furthermore, 72 estuarine fishes from 31 families were recorded from previous data and during this field survey which gives a total of 161 freshwater/estuarine fish species from 45 families in Fiji. This study has contributed 11 new records and a new genus to the total number of brackish and freshwater fishes of Fiji. The new species are Glossogobius sp., Redigobius sp., Sicyopus (c.f. Juxtastiphodon) sp., Stenogobius sp., Stiphodon sp. 1, Stiphodon sp. 2 and Sicydiinae: new genus and new species. One of the new species was already described by Jenkins and Boseto (2005) as Schismatogobius vitiensis. The new records are Yirrkala gjellerupi, Gerres longirostris, Lentipes kaaea and Belobranchus belobranchus. The “Inter Quartile Range” and multiple regression analyses were used to analyse the data collected from this survey. “Inter Quartile Range” analysis was used to describe how common were the fish species caught from the different sites collected during this survey, other collections and the combine collections. Multiple regression analyses were used to examine the relationships iii between physical habitat characteristics and freshwater fish species richness and abundance. SPSS Version 11.5 for Windows was used for all analyses and Į was set at 0.05 for all analyses. Anguilla marmorata (Anguillidae) was the most common species collected during this survey. The common species after combining all the collections are Anguilla marmorata (Anguillidae), and Kuhlia rupestris (Kuhliidae). The moderate to occasionally common and the least common fish species of the combined collections are in Appendix 6. This study shows species richness depends on physical habitat factors, mainly water temperature and river depth for total number of fish species and number of native species and distance from the coast for endemic species. The number of introduced fish species decreased with distance from the coast (p = 0.001). Species abundance depends on physical habitat factors such as water temperature for the total number of fish species and number of native species. In this survey it was found that there is greater species richness in the estuarine zone and lower reaches of freshwater. Species richness decreases as one moves inland to the mid reaches and is lowest in the headwaters. Fiji has the Environment Management Act and is signatory to international conventions (CITES, CBD, RAMSAR) that have legislation to protect Fiji’s biodiversity. Therefore, findings from this survey should help decision makers to recognize the importance of the flora and fauna of the rivers, streams, creeks and lakes, and protect them. Once care is given to the aquatic systems, it will help take care of the whole ecosystem. iv DEDICATION This thesis is dedicated to my beloved father the late Mr. David Pitisopa Boseto, who was called to rest on December 22nd, 2004 by the Almighty GOD. This was six weeks before the completion of the first draft of this thesis. This is a product of your faith in me to allow me to continue with my studies. I wouldn’t have come this far if it wasn’t for your commitment, in persuading me to be successful in whatever things I do in life. You have also taught me how to love and care for nature. Therefore, that’s one thing I’ll continue to do and advocate to our people the importance of these creatures and how to look after them as required by the Creator. Thank you Dad for being my dear father and I thank GOD for your life. I’ll say bye to you for now but my hope is “for in awhile” to see you again. v ACKNOWLEDGEMENT This study could not have been completed without the help of a considerable number of people, friends and families whose help and support I must salute. First and foremost I would like to thank GOD for the gift of life. I want to thank Him, Praise Him, and give him all the credit for what He has done for me. Secondly, to Professor William Aalbersberg, for securing funds from the University of Utah (2001) and the John D. and Catherine T. MacArthur Foundation (2002 – 2005) to fund my studies. In addition, the University of the South Pacific for providing a research grant for fieldwork and the Institute of Marine Resources for purchasing the electro fishing machine for my study. I would like to thank the Department of Forestry and Public Works Department for granting me permission to do the work in Savura Creek, the Naitasiri Provincial Council, the Roko Tui of Cakaudrove Provincial Council in Taveuni and the Turaga ni Koro of Korovou Village (Taveuni), for allowing me to do the work in Tavoro Creek. Samplings at the other sites were made possible through the arrangements between the South Pacific Regional Herbarium and the landowners. My sincere thanks to Messrs, Marika Tuiwawa, Alivereti Naikatini, Isaac Rounds, Timoci Koliyavu, Fred Pitisopa, Ms. Nunia Thomas and Dr. Clare Morrison from the South Pacific Regional Herbarium in Suva and all the Marine Studies Programme and Institute of Applied Sciences postgraduate students and staff for giving me valuable advice and company while carrying out this study. To Marine Studies Program and Institute of Applied Sciences secretaries and clerical officers, Mesdames Nanise Bulai, Fulori Bulai, Susan Naco, Aisha Khan, Frances Lee and Reena Sagar, a very big vinaka vaka levu to you all for giving me all the support and help with administration and logistics, MSP drivers for transportations and workshop workers for their assistance: Messrs Sunia Lavaka, Jone Lima and Shiv Sharma for field logistics, equipment and laboratory space. I would also thank the late Mr. Peni Bulivakarua for making life more interesting while doing my studies and also the late Mr. Suren Chand for sewing the fishing nets for me. Foeksia aka to Mr. Sidney Malo for being my field assistant in Taveuni and the Tamavua River system. vi I am greatly indebted to the following people: Mr. Aaron Jenkins, Mr. Johnson Seeto and Dr. Patricia Kailola for allowing me to use their fish books, their comments, advice and support towards my work; Dr. Clare Morrison for her contribution in statistics, organization of my thesis and reading the first drafts, Mr. Roger Jaensch (Wetlands International) for his comments on chapters three, four and five. Dr. Patricia Kailola for mentoring, reorganization, and editing of the whole thesis; Mr. Baravi Thaman (University of the South Pacific) and Ms. Leary Cokonasiga (Wildlife Conservation Society) for maps. I am also very thankful for the support that I received through corresponding with the following people who provided me with electronic and hard copies of their published papers, Dr. R.M. McDowall, Dr. Andrew W. Storey, Dr. Ronald Watson, Ms Roselyn Kumar, Mr. Gunnar Keppel and Professor Randy Thaman. I would also like to extend my heartfelt thank you for people who always help me out when I need their help by continuing to communicate my work with Dr Helen Larson, Mr. Mark McGrouther and Dr. Ronald Watson. I am indebted to the following specialists who provided assistance by identifying specimens and confirming some of my identifications: Mr. Johnson Seeto, University of the South Pacific (Lutjanidae and Crabs), Dr. Douglass F. Hoese, Australian Museum Sydney (Glossogobius sp. 1 and Eleotridae), Dr. Helen Larson Northern Territory Museum, Darwin (Redigobius leveri), Dr. Gerry Allen, Western Australia Museum, Perth (Schismatogobius vitiensis), Dr. John McCosker, California Academic of Science, San Francisco, U.S.A. (Eels) and Dr. Ronald Watson, Florida (Stenogobius sp. 1 and Sicydiinae). Dr. Patricia Kailola (Sydney) and Mr. Aaron Jenkins (Wetlands International, Oceania) confirmed all the other fish species. I would also like to thank Mr.