Environmental Biology of Fishes

, Volume 54, Issue 4, pp 389–404

Fishes of floodplain habitats of the Fly River system, Papua New Guinea, and changes associated with El Niño droughts and algal blooms

  • Stephen Swales
  • Andrew W. Storey
  • Ian D. Roderick
  • Boga S. Figa
Article
  • 132 Downloads

Abstract

Biological monitoring of the Fly River system in Papua New Guinea has shown that floodplain habitats (oxbow lakes, blocked valley lakes and seasonally inundated grassed floodplain) support diverse and abundant populations of freshwater fishes. Since monitoring first commenced in the early 1980's, a total of 66 fish species representing 33 families has been sampled, with gillnets and rotenone, from a range of sites located on the floodplains of the Fly and Strickland rivers. The fish fauna was dominated by catfishes in the families Ariidae (11 species) and Plotosidae (7 species), with aquatic invertivores being the dominant feeding group. Herring species (Nematalosa spp.) were often very abundant in the oxbow lakes, forming 66% of the total catch in all the floodplain habitats. The fish communities in the oxbow lakes and blocked valley lakes were distinctly different, with several of the smaller fish species being more abundant in the blocked valley lakes, while the oxbow lakes supported more of the larger predatory species. Catches in the oxbow lakes were also generally higher and more diverse than the blocked valley lakes or grassed floodplain sites. Since the commencement of monitoring, catches from the floodplain sites have varied considerably, both spatially and temporally. Reduced catches seen at some sites are probably associated with natural climatic factors, particularly ‘El Niño’-induced droughts and algal blooms. Introduced species and increased commercial and artisanal fishing may also be affecting stocks of native fish. Fish populations were shown to recover only slowly in lakes affected by severe drought conditions, with extensive mats of floating grasses hindering fish recolonisation. Fish stocks in a lake affected by an algal bloom recovered more quickly than stocks in lakes affected by drought.

oxbow lakes fish catches biomonitoring species richness Strickland River 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References cited

  1. Allen, G.R. 1991. Field guide to the freshwater fishes of New Guinea. Publication No. 9 of the Christensen Research Institute, Madang. 268 pp.Google Scholar
  2. Busse, M. 1991. Environment and human ecology in the Lake Murray — Middle Fly area. pp. 441–449. In: D. Lawrence & T. Cansfield-Smith (ed.) Sustainable Development for Traditional Inhabitants of the Torres Strait Region, Proceedings of the Torres Strait Baseline Study Conference, Workshop Series No. 16, Great Barrier Reef Marine Park Authority, Townsville.Google Scholar
  3. Chambers, M.R. 1988. Dissolved oxygen, temperature and zoo-plankton studies of lakes Bosset, Pangua and Daviambu, pp. 19–30. In: U.N.E.P. Regional Seas Reports and Studies No. 99, United Nations Environment Programme.Google Scholar
  4. Coates, D. 1993. Fish ecology and management of the Sepik-Ramu, New Guinea, a large contemporary tropical river basin. Env. Biol. Fish. 38: 345–368.Google Scholar
  5. Halse, S.A., G.B. Pearson, R.P. Jaensch, P. Kulmoi, P. Gregory, W.R. Kay & A. W. Storey. 1995. Waterbird surveys of the Middle Fly River floodplain, Papua New Guinea. Wildlife Research 23: 557–569.Google Scholar
  6. Higgins, R.J. 1990. Off-river storages as sources and sinks for environmental contaminants. Regulated Rivers Research & Management 5: 401–412.Google Scholar
  7. Lowe-McConnell, R.II. 1987. Ecological studies in tropical fish communities. Cambridge University Press, Cambridge. 382 pp.Google Scholar
  8. Munro, I.S.R. 1967. The fishes of New Guinea. Department of Agriculture, Stock & fisheries, Port Moresby. 651 pp.Google Scholar
  9. Roberts T.R. 1978. An ichthyological survey of the Fly River in Papua New Guinea with descriptions of new species. Smith-sonian Contributions to Zoology 281; 1–72.Google Scholar
  10. Smith, R.E.W. & K.A. Bakowa, 1994. Utilisation of floodplain waterbodies by the fishes of the Fly River, Papua New Guinea. Mitt. internal. Verein. Limnol. 24:187–196.Google Scholar
  11. Smith, R.E.W. & K.G. Horde. 1991. Assessment and predictions of the impacts of the Ok Tedi copper mine on fish catches in the Fly River system, Papua New Guinea. Env. Monitoring & Assessment 14: 315–331.Google Scholar
  12. Stauber, J.L. 1995. Toxicity testing using marine and freshwater unicellular algae. Aust. J. Ecotoxicology 1: 15–24.Google Scholar
  13. Swales, S., A.W. Storey & K.A. Bakowa. 1998. Biological monitoring of the effects of the Ok Tedi copper mine on fish populations in the Fly River system, Papua New Guinea. Science of the Total Environment 214: 99–111Google Scholar
  14. Swales. S., A. W. Storey & K.A. Bakowa. 1999. Temporal and spatial variations in fish catches in the fly river system in Papua New Guinea and the possible effects of the Ok Tedi copper mine. Env. Biol fish. (in press).Google Scholar
  15. Welcomme, R.L. 1979, Fisheries ecology of floodplain rivers, Longman, London. 317 pp.Google Scholar
  16. Welcomme, R.L. 1985. River fisheries. FAO Technical Paper 262, Rome 330 pp.Google Scholar
  17. Winemiller, K.O. 1996. Dynamic diversity in fish assemblages of tropical rivers. pp. 99–134. In: M.L. Cody & J.A. Smallwood (ed.) Long-Term Studies of Vertebrate Communities, Academic Press, San Diego.Google Scholar

Copyright information

© Kluwer Academic Publishers 1999

Authors and Affiliations

  • Stephen Swales
    • 1
  • Andrew W. Storey
    • 2
  • Ian D. Roderick
    • 1
  • Boga S. Figa
    • 1
  1. 1.Environment DepartmentOk Tedi Mining Ltd.TabubilPapua New Guinea (e-mail
  2. 2.Department of ZoologyThe University of Western AustraliaNedlandsAustralia (e-mail

Personalised recommendations