Freshwater ichthyofauna of the Pacific-Asia Biodiversity Transect (PABITRA) Gateway in Viti Levu, Fiji

Abstract

The freshwater ichthyofauna of the Fiji islands remained poorly documented before the establishment of the Pacific-Asia Biodiversity Transect (PABITRA) network. The PABITRA approach assesses biodiversity along ocean-to-mountain transects and promotes sustainable land use on islands across the Pacific. Multiple surveys of freshwater fish species along the Viti Levu PABITRA transect have contributed six new occurrence records and one new species to the known freshwater fishes of Fiji since 2002. In total, 21 indigenous species of fish (9% endemic) from 10 families and no introduced fishes were found in the three PABITRA sites. Diversity was highest (16 species) at Savura forest reserve and decreased further inland into Sovi and Wabu. The assemblage found is dominated by highly migratory species (95%) that traverse the different aquatic habitats (marine, estuarine, lowland and upland streams) covered by the PABITRA transect. This high degree of connectivity highlights several growing issues affecting aquatic fauna on the high island of Viti Levu. The reduction in forest cover along the gateway transects, especially in the terminal reaches, and infrastructure development such as dams and weirs have deleterious effects on the migration routes of the Fijian ichthyofauna. Several species collected are important food sources and have cultural totemic importance to local inhabitants along the vertical transect. This paper documents the ichthyofauna of the Fiji gateway transect, ecological characteristics of this assemblage, IUCN Redlist conservation assessment status and highlights factors affecting the fragility and resilience of these communities, particularly focusing on the importance of life-history patterns and watershed conditions.