Subject: Abstract - humpback whales (fwd)

Michael Williamson (
Tue, 6 Aug 1996 15:48:02 -0400 (EDT)


---------- Forwarded message ----------
Date: Tue, 6 Aug 1996 07:41:50 EST
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