Performance of Baited Underwater Video: Does It Underestimate Abundance at High Population Densities?
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AuthorsStobart, B. (Ben); Díaz, D. (David); Álvarez, F. (Federico); Alonso, C. (Cristina); Mallol, S. (Sandra); Goñi, R. (Raquel)
Editor/sHewitt, J. (Judi)
marine protected area
Abstract Video survey techniques are now commonly used to estimate animal abundance under the assumption that estimates relate to true abundance, a key property needed to make video a valid survey tool. Using the spiny lobster Palinurus elephas as our model organism, we evaluate the effectiveness of baited underwater video (BUV) for estimating abundance in areas with widely different population density. We test three BUV abundance metrics and compare the results with an independently obtained abundance index from trammel-net surveys (Trammel). Video metrics used to estimate relative abundance include a value for total number of individuals per recording (TotN), the traditional maximum number of fish observed in a single video frame (MaxN) and the recently suggested alternative, the average of the mean MaxN from 5-minute periods throughout the duration of the recording (MeanN). This is the first video study of a wild population to include an estimate for TotN. Comparison of TotN with the ...