Subject: Abstract - humpback whales (fwd)
Michael Williamson (pita@whale.simmons.edu)
Tue, 6 Aug 1996 15:48:02 -0400 (EDT)
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---------- Forwarded message ----------
Date: Tue, 6 Aug 1996 07:41:50 EST
From: Dagmar_Fertl@smtp.mms.gov
To: Multiple recipients of list MARMAM <MARMAM@UVVM.BITNET>
Subject: abstract - humpback whales
Findlay, K.P. and P.B. Best. 1996. Assessment of heterogeneity in
sighting probabilities of humpback whales within viewing range of Cape
Vidal, South Africa. Marine Mammal Science 12(3): 335-353.
(Mammal Research Institute, c/o S A Museum, P.O. Box 61, Cape Town,
8000, South Africa)
The migrations of humpback whales on the African east coast were
monitored between 1988 and 1991 at Cape Vidal, South Africa.
Shore-based surveys of the northward migration were undertaken each
winter, and a survey of the southward migration was undertaken in
1990, from an approximately 60-m-high vantage point on a headland.
Independent-observer surveys were carried out in both 1990 (22 d) and
1991 (51 d) to determine the proportion of the population within the
survey area that were being missed by observers using a single
mark-release model. Results were stratified into three distance
intervals from the shore and three sighting condition intervals; there
were constant sighting probabilities from the south tower under
different sighting conditions, while those from the north tower
increased slightly as sighting conditions improved. Sighting
probabilities from both towers were highest in the intermediate
distance interval and decreased in both the inshore and offshore
regions.