An Evaluation of Some Techniques for Aerial Censuses of Bottlenosed Dolphins

Publication Type:Journal Article
Year of Publication:1978
Authors:Leatherwood, S, Gilbert, JR, Chapman, DG
Journal:The Journal of Wildlife Management
Volume:42
Date Published:1978
ISBN Number:0022541X
Keywords:Tursiops truncatus
Abstract:

Surveys were conducted from aircraft over waters off the coasts of Louisiana, Mississippi, and Alabama during the summers of 1974 and 1975 to evaluate field procedures and analytical techniques for estimating population densities of bottlenosed dolphins (Tursiops truncatus). Samples using a strip proved more reliable than those based on a quadrat. Line-transect estimates were generally not feasible because the observed distribution of distances from the flight line was different from the theoretical distribution required. Differences in counts between observer teams were significant. Based on strip censuses, the following population estimates were obtained: western Louisiana (1975), 897 ± 461; Mississippi, Chandeleur and Breton sounds, marshlands habitats (1974) 438 ± 294; and Mississippi Sound 1,342 ± 847 (1974) and 879 ± 368 (1975). The differences in the last 2 estimates reflect the large variability inherent in the population and in the estimation procedure and are not indicative of population fluctuation. Suggestions are made for future censuses of dolphins inhabiting inshore waters.

URL:http://www.jstor.org/stable/3800261
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Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith