MEPS 244:89-93 (2002)  -  doi:10.3354/meps244089

ABSTRACT: The standard method for collecting information on both the abundance and distribution of surface-dwelling megafauna, and biotic sediment-features associated with burrowing megafauna has been direct observation and counting by divers. However, remote observations allow information comparable to diver observations to be applied to investigations at greater depths and over wider spatial extents than divers may achieve. The present paper compares abundance estimates of megafaunal biotic sediment-features obtained from diver and remotely operated vehicle-mapping techniques. Results show strong agreement between estimates of total-feature and conspicuous-feature abundance, providing assurance that remote observation techniques are not subject to systematic errors in estimation of feature abundance. The ability to detect the smallest features appeared to differ between observation techniques, but this was an artefact caused by measurement of features rather than feature detection. A laser diode array attached to the camera to quantify image scale increased the amount of quantitative data that may be extracted from remote images.

KEY WORDS: Megafauna · SCUBA diving · Remotely operated vehicle · Spatial variation · Image scaling