Light-Traps: Selective but Useful Devices for Quantifying the Distributions and Abundances of Larval Fishes

An inexpensive automated light-trap has shown great potential as a tool for quantifying spatial and temporal patchiness in assemblages of larval fishes. Automation means that simultaneous samples can be collected within narrow time-windows from multiple locations. With the right sampling design, synoptic maps of larval abundance can be produced with a resolution equivalent to the density of traps. Because the traps do not kill like other techniques, it is far easier to resolve the distributions of individual species and the live larvae can be used for further experimentation. Some data from Lizard Island, northern Great Barrier Reef, are reported to demonstrate the utility and the limitations of this technique.