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11. Acoustic Telemetry: Harbour porpoises and seals
Jonas Teilmann 1 , Rune Dietz 1 , Peter T. Madsen 2 , Danuta Wisniewska 2 , Mark Johnson 3 , Lee A.
Miller 4 (presenter), Ursula Siebert 5
1
Institut for Bioscience, Aarhus Universitet jte@dmu.dk, rdi@dmu.dk
2
Institut for Bioscience, Aarhus Universitet, Ny Munkegade 116, 8000 Aarhus C
peter.madsen@biology.au.dk, biodmw@biology.au.dk
3
SMRU, Scottish Oceans Institute, University of St Andrews, St Andrews, Fife, KY16 8LB, UK
markjohnson@st-andrews.ac.uk
4
Biologisk Institut, Syddansk Universitet, Campusvej 55, 5230 Odense M lee@biology.sdu.dk
5
Stiftung Tierärztliche Hochschule Hannover, Bünteweg 2, 30559 Hannover, Tyskland
ursula.siebert@tiho-hannover.de
The German Bundesamt für Naturschutz (BfN) finances an extensive environmental impact
initiative in connection with the establishment of offshore wind turbine parks. One of the programs
involves underwater sound, the head of which is Prof. Ursula Siebert. The Institute of Bioscience
(AU), and The Sea Mammal Research Unit (SMRU) have responsibility for developing and
constructing a behavioral tag, to deploy tags on harbour porpoises and harbour seals, and to
evaluate the responses of the tagged animals to the acoustic environment. The prototype of the
archival tag (Dtag3) contains two hydrophones and electronics to provide an acoustic bandwidth
from 50 Hz to 160 kHz thus covering the full auditory range of both harbour porpoises and harbour
seals. Since the hydrophones are calibrated, the level of received sound can be measured. In
addition to monitoring the acoustic behavior of the tagged animal in response to extraneous sound,
movements can be monitored by a tri-axial accelerometer and dive depth can be measured. In the
final version of the tag a GPS position will be acquired (in 50 ms) each time the animal surfaces.
Four suction cups hold the tag on the porpoise and when the suction is released the tag floats to the
surface where an Argos satellite transmitter and a VHF radio start transmitting. The Argos system
determines the general position of the tag within 30 min and the radio signal assists finding the tag
at close range. The prototype Dtag3 has recently been attached to two harbor porpoises in the
waters off Djursland on two separate occasions, in the first case the recording time was 22 h and in
the second 18 h. Dive behavior of the second animal is shown in the figure. Feeding attempts, as
indicated by “buzzes” in the acoustic signal, were heard from both tagged animals. A young
individual, presumably an offspring, accompanied the second tagged animal, and feeding attempts
could be heard by this individual also. Echoes from objects (probably prey) could also be recorded.
Ship noise was obvious. Details of the recordings await analysis, but the conclusion is that the
proto-type Dtag3 tested successfully and the project will certainly provide valuable information
concerning the effects of anthropogenic sounds on harbour porpoises and seals during deployments
in 2013-14.
The figure shows the full 18 hr dive profile of a
harbor porpoise carrying an archival tag (Dtag3). It
dove to a maximum depth of 30 m in the Kattegat.
The dive behavior appears quite normal as
compared to that of other porpoises tagged with
another system.
Major funding for the Underwater Sound program from BfN. Additional funding from AU.
Program 17. danske havforskermøde, 31