Abstract for presentation at Biodiversity Extinction Crisis Conference - A Pacific Response

Fiji’s freshwater fish fauna currently consists of 89 species from 26 families and occurs in a range of habitats from lowland estuaries to the montane headwaters of streams and rivers. There have been no studies which document the relationship between physical parameters and freshwater fish distribution in Fiji. Therefore, the aims of this study were to determine physical habitat characteristics that affect freshwater fish species richness and abundance in Fiji. Between 2002 and 2005 baseline fish surveys were carried out in 66 sites in Fiji. Surveys were conducted using a range of techniques including cast net, beach seine net, fine mesh net, pole seine net, hand net, spear gun, electro fisher machine and visual observation. We found 76 fish species from 31 families during the surveys representing 85% of all known freshwater fish in Fiji. Total species richness in each site ranged from 0-18 species with an average of 5.67 ± 3.49 fish per site. Native species were the most common (63 species) followed by endemic species (9) and introduced species (4). Water temperature was the most important factor influencing total species richness and abundance. Endemic species richness increased with distance from the coast while more introduced fish were found in coastal areas. Most of these results are similar to those of previous studies of freshwater fish distribution elsewhere. This study highlights the importance of surveying freshwater fish in multiple sites to provide the range of physical habitat conditions needed to determine the factors influencing freshwater fish distribution and diversity. Future surveys will involve more quantitative surveys in different seasons and over time to monitor the long-term variation in the diversity and abundance of freshwater fish species in Fiji.