WAMSI Node 4.2.4 - Demersal fish assemblage sampling method comparison and power analyses - Summary

The principal goal of this research was to investigate the most efficient, cost-effective and meaningful way of describing the structure and biodiversity of seabed habitats along the coastline of WA. This study used existing data obtained from three regions (Ningaloo, Abrolhos and Capes) to compare techniques including comparing diver vs camera-based techniques for fish. The first study compared the assemblage composition, relative abundance and size of fishes sampled using baited video and diver swum transects at the Houtman Abrolhos Islands and Ningaloo. At both locations stereo BRUV recorded many more targeted fishes than stereo DOV and in greater relative abundance (e.g. Lethrinus nebulosus, Plectropomus leopardus). Many non-targeted species were also attracted to bait (e.g. Coris auricularis) and were recorded in greater abundances on stereo BRUV than stereo DOV. Stereo DOV transects recorded a greater abundance of some small-bodied Pomacentridae, Labridae and Scaridae species than did stereo BRUV, particularly at Ningaloo. This study demonstrates that choice of stereo-video sampling technique for surveys of reef fish can have a large impact on the structure of fish assemblages surveyed. A link to the paper "Assessing reef fish assemblage structure: how do different stereo-video techniques compare?" by Dianne L. Watson, Euan S. Harvey, Ben M. Fitzpatrick, Timothy J. Langlois and George Shedrawi is given in a URL below (see online resource) and provides further details The second study compares baited video stations with diver swum transects across three biogeographic regions, where both methods use stereo-video techniques to provide accurate estimates of individual fish length and define the sample unit area (Langlois et al. submitted). Cost-benefit analyses showed that baited stereo-video methods were generally more cost-efficient than diver operated stereo-video transects for detecting change in the fish assemblage. The study suggests that baited stereo-video stations are, in general, a better method for monitoring fish communities than diver operated stereo-video transects. A link to the paper "Cost efficient sampling of fish assemblages: comparison of baited video stations and diver video transects" by T.J. Langlois, E. S. Harvey, B. Fitzpatrick, J. J. Meeuwig, G. Shedrawi, and D. L. Watson is given in a URL below (see online resource) and provides further details. Langlois, T. J., E. S. Harvey, B. Fitzpatrick, J. J. Meeuwig, G. Shedrawi, and D. L. Watson. 2010. Cost efficient sampling of fish assemblages: comparison of baited video stations and diver video transects. Aquatic Biology 9:155-168. Watson, D. L., E. S. Harvey, B. Fitzpatrick, T. J. Langlois, and G. Shedrawi. 2010. Assessing reef fish assemblage structure: how do different stereo-video techniques compare? Marine Biology 157:1237-1250.