Subject: Abstract: Dall's porpoise reactions to tagging attempts (fwd)

Mike Williamson (
Wed, 7 Oct 1998 13:32:44 -0400 (EDT)


---------- Forwarded message ----------
Date: Wed, 7 Oct 1998 13:23:40 -0400
From: "Robin W. Baird" <rwbaird@IS.Dal.Ca>
Subject: Abstract: Dall's porpoise reactions to tagging attempts

Hanson, M.B., and R.W. Baird. 1998. Dall's porpoise reactions to
tagging attempts using a remotely-deployed suction-cup tag. Marine
Technology Society Journal 32(2):18-23.


Remotely-deployable non-invasive (suction-cup attached) tags to record
underwater behavior of cetaceans have recently been developed. How
useful these tags are for applications on a broad range of species has
yet to be documented. However, we attempted to use such tags to study
the diving behavior of Dall's porpoise (Phocoenoides dalli) in the
trans-boundary area of British Columbia and Washington state, and
report here on the feasibility of the technique, including the
reactions of Dall's porpoise to tagging attempts. Tagging activities
were undertaken in August 1996, while porpoises were bow-riding on a
small vessel. We made 15 tagging attempts, and 13 resulted in tag
contact with a porpoise. No reactions were observed for the two
misses, nor for 2 of the 13 hits. Of the 11 cases when tag reactions
were observed, porpoises returned to continue bowriding almost
immediately in 7 cases, suggesting no long-term effect. Short-term
reactions observed included a flinch (9 of 13 hits), tailslap (1 of 13
hits) and high speed swimming away from the vessel (4 of 13 hits),
with some hits resulting in more than one type of reaction. Three of
13 hits resulted in successful tag attachment. One tag remained
attached for 41 minutes, providing the first diving behaviour data for
this species. Rates of descent and ascent, as well as swimming
velocity, were relatively high only for the first 6-8 minutes after
tag attachment, suggesting a reaction to tagging that lasted
approximately 8 minutes.

Reprints may be obtained from either author (Brad Hanson -; Robin Baird -

Robin W. Baird, Ph.D.
Biology Department, Dalhousie University, 1355 Oxford St.,
Halifax, Nova Scotia B3H 4J1 Canada
Phone (902) 494-3723
Fax (902) 494-3736