QUANTIFYING SUBTIDAL MACROBENTHIC ASSEMBLAGES ON HARD SUBSTRATA USING A JUMP CAMERA METHOD

A quantitative technique for sampling macrobenthic assemblages on hard substrata that can be used in depths up to 100 m has been developed. A jump camera was built that recorded 0.45 m2 photo-quadrats of sublittoral macrobenthos. An experiment was done which compared photo-quadrats collected by the jump camera with quadrats collected in situ by SCUBA divers. This was done in habitats dominated by erect organisms (sponges, bryozoans etc.) and by flat, prostrate organisms. Results showed that there was little difference in accuracy or time required using the two techniques in both habitats. Both techniques demonstrated greater species richness and abundance in habitats dominated by erect species. Individual species of sponges, bryozoans, cnidarians and ascidians were accurately sampled using both techniques. The time required for the two techniques showed that, on average, jump camera sampling took almost-equal-to 10% longer than diver sampling because of the time required to interpret photographs in the laboratory. The jump camera method is now being used in a sewage outfall monitoring program to assess spatial and temporal differences in macrobenthic assemblages living on hard substrata in deep water off the coast of Sydney, NSW, Australia.