Visual Census of Reef Fish Assemblages: A Comparison of Slate, Audio, and Video Recording Devices

Fish assemblage data were recorded using slate, audio, and video techniques with a point-count visual census technique under controlled conditions. The community variables (number of species, number of individuals, and species diversity) describing the assemblage were generally similar for all three recording methods but audio recorded parameters were higher in magnitude. Slate and audio techniques were more similar to each other than each was to video with regard to the assemblage variables. Community resemblances were high for pairwise comparisons for all three recording methods. Users should be aware that certain species are more likely to contribute to differences in faunal comparisons than others. The simultaneous recording of fish assemblage date in situ using audio/video is recommended. There has been much recent interest in obtaining accurate and precise in situ data on the fish assemblages associated with both natural and artificial reefs. These data are needed to assess and monitor these biotopes as well as test various ecological hypotheses (e.g., Bohnsack and Sutherland, 1985; Hixon and Beets, 1989; Sale 1980). Concomitant with the increase in intere,st in obtaining these data has been the implementation of a variety of sampling methods (e.g., Barans and Bartone, 1983; HarmelinVivien eta/., 1985). Evaluating the implementation of these methods under various conditions has also been the subject of many recent studies as well (Bartone, Hastings, and Oglesby, 1986; Bartone, Kimmel, and Bundrick, 1989; Brock, 1982; DeMartini and Roberts, 1982; Kimmel, 1985; Sale and Douglas, 1981; Sale and Sharp, 1983; Sanderson and Solonsky, 1986; Thresher and Gunn, 1986). Somewhat separate from the methods used to assess fish assemblages in situ is the 17 technique used to record the data. The "standard" technique of writing data on an underwater slate (Helfman, 1983) has given way to more sophisticated audio, video, and audio/video recording devices (e.g., Alevizon and Brooks, 1976; Bartone et at., 1986; Smith and Tyler, 1973). While each of these in situ data recording techniques has advantages and disadvantages it is especially significant for researchers to be aware of the effect that different methods of data recording may have on the statistical description of the faunal assemblage. This is especially true when comparing data that have been recorded by different methods within a study or when comparisons are being made to previously published studies using differnt recording techniques. Greene and Alevizon (1989) recently conducted a preliminary evaluation of different in situ recording techniques as part of a general comparison of several visual assessment methods. The present study is a more detailed examination of 1 Bortone et al.: Visual Census of Reef Fish Assemblages: A Comparison of Slate, Au Published by The Aquila Digital Community, 1991 18 Bartone, Stephen A., and Charles M. Bundrick their initial assessment. We compare faunal population variables as attributes of the data recording technique to determine which are comparable between recording techniques. Also, we examine the factors attributable to faunal composition that most significantly affect the comparison. The results herein should facilitate the decision process when researchers choose recording techniques