Freshwater fish survey methodology for streams & rivers on tropical oceanic islands: a brief guide based on the freshwater survey work conducted as part of the Fiji Ecosystem Based Management Project

Abstract

Streams and rivers on islands are considerably different to continental systems in that oceanic island systems are often subject to recurrent flash flooding and many fauna in continental systems are only distantly related to island fauna, rarely having an obligate marine larval phase of their life cycles. Several methods used in surveying continental systems are therefore only of limited applicability in island systems. The field procedures described herein are loosely adapted from those described in Parham, 2005 and Fitzsimons et. al., 2007 and refined from the field experiences of the author. These methods are designed to provide the most comprehensive documentation of fishes present in a variety of stream and river habitats in tropical oceanic island ecosystems while also providing an accurate snapshot of the habitable space. In our study for the Fiji Ecosystem Based Management (EBM) project we used fishes, particularly gobioid (Families Gobiidae & Eleotridae) as primary indicators of environmental quality as fishes are taxonomically most well studied and most observable inhabitants of these systems, represent critical components of the food web from primary consumers (herbivores) to predators and because of their recognized value as a food source for inland communities