Passive acoustic monitoring (PAM) is a widely used technique for studying the distribution and habitat use of cetaceans. The C-POD, an acoustic sensor with an onboard automated click detector, has been deployed in diverse acoustic environments, but studies verifying its offshore detection rates and factors affecting detection probability are scarce. To empirically evaluate the performance of C-PODs in detecting bottlenose dolphins (Tursiops truncatus), C-PODs were deployed alongside archival acoustic recorders 12–30 km offshore in the Northwest Atlantic Ocean. The C-POD and acoustic recordings, post-processed using PAMGUARD software, were compared for a period of 6852 h. C-POD false positive rates were very low (mean 0.003%), and positive hourly detection accuracy was very high (mean 99.6%). Analysis of the acoustic environment and dolphin click characteristics revealed that true positive detections by C-PODs were significantly more likely to occur when PAMGUARD detected more clicks and there was increased high frequency noise (>20 kHz), likely from distant or unclassified clicks. C-PODs were found to be reliable indicators of dolphin presence at hourly or greater time scales. These results support the application of C-PODs in PAM studies that aim to investigate patterns of dolphin occurrence, such as those related to offshore windfarms.

1.
Au
,
W. W. L.
(
1993
).
Sonar of Dolphins
, (
Springer-Verlag
,
New York
).
2.
Au
,
W. W. L.
,
Branstetter
,
B.
,
Moore
,
P. W.
, and
Finneran
,
J. J.
(
2012
). “
The biosonar field around an Atlantic bottlenose dolphin (Tursiops truncatus)
,”
J. Acoust. Soc. Am.
131
,
569
576
.
3.
Au
,
W. W. L.
,
Floyd
,
R. W.
,
Penner
,
R. H.
, and
Murchison
,
A. E.
(
1974
). “
Measurement of echolocation signals of the Atlantic bottlenose dolphin, Tursiops truncatus Montagu, in open waters
,”
J. Acoust. Soc. Am.
56
,
1280
1290
.
4.
Bailey
,
H.
,
Brookes
,
K. L.
, and
Thompson
,
P. M.
(
2014
). “
Assessing environmental impacts of offshore wind farms: Lessons learned and recommendations for the future
,”
Aquat. Biosyst.
10
,
1
13
.
5.
Bailey
,
H.
,
Clay
,
G.
,
Coates
,
E. A.
,
Lusseau
,
D.
,
Senior
,
B.
, and
Thompson
,
P. M.
(
2010
). “
Using T-PODs to assess variations in the occurrence of coastal bottlenose dolphins and harbour porpoises
,”
Aquat. Conserv. Mar. Freshw. Ecosyst.
20
,
150
158
.
6.
Barco
,
S. G.
,
Swingle
,
W. M.
,
McLellan
,
W. A.
,
Harris
,
R. N.
, and
Pabst
,
D. A.
(
1999
). “
Local abundance and distribution of bottlenose dolphins (Tursiops truncatus) in the nearshore waters of Virginia Beach, Virginia
,”
Mar. Mammal Sci.
15
,
394
408
.
7.
Brookes
,
K. L.
,
Bailey
,
H.
, and
Thompson
,
P. M.
(
2013
). “
Predictions from harbor porpoise habitat association models are confirmed by long-term passive acoustic monitoring
,”
J. Acoust. Soc. Am.
134
,
2523
2533
.
8.
Bureau of Ocean and Energy Management (BOEM), National Oceanographic and Atmospheric Administration (NOAA)
(
2013
).
2013 Vessel Density
, available at https://marinecadastre.gov/ais/ (Last viewed 01/10/2018).
9.
Castellote
,
M.
,
Leeney
,
R. H.
,
O'Corry-Crowe
,
G.
,
Lauhakangas
,
R.
,
Kovacs
,
K. M.
,
Lucey
,
W.
,
Krasnova
,
V.
,
Lydersen
,
C.
,
Stafford
,
K. M.
, and
Belikov
,
R.
, (
2010
). “
Monitoring white whales (Delphinapterus leucas) with echolocation loggers
,”
Polar Biol.
,
36
,
493
509
.
10.
Carstensen
,
M.
,
Henriksen
,
O. D.
, and
Teilmann
,
J.
, (
2006
). “
Impacts of offshore wind farm construction on harbour porpoises: Acoustic monitoring of echolocation activity using porpoise detectors (T-PODs)
,”
Mar. Ecol. Prog. Ser.
,
321
,
295
308
.
11.
Clark
,
C. W.
,
Brown
,
M. W.
, and
Corkeron
,
P.
(
2010
). “
Visual and acoustic surveys for North Atlantic right whales, Eubalaena glacialis, in Cape Cod Bay, Massachusetts, 2001–2005: Management implications
,”
Mar. Mammal Sci.
26
,
837
854
.
12.
Cox
,
S. L.
,
Witt
,
M. J.
,
Embling
,
C. B.
,
Godley
,
B. J.
,
Hosegood
,
P. J.
,
Miller
,
P. I.
,
Votier
,
S. C.
, and
Ingram
,
S. N.
(
2017
). “
Temporal patterns in habitat use by small cetaceans at an oceanographically dynamic marine renewable energy test site in the Celtic Sea
,”
Deep Sea Res. Part II Top. Stud. Oceanogr.
141
,
178
190
.
13.
Dähne
,
M.
,
Gilles
,
A.
,
Lucke
,
K.
,
Peschko
,
V.
,
Adler
,
S.
,
Krügel
,
K.
,
Sundermeyer
,
J.
, and
Siebert
,
U.
(
2013
). “
Effects of pile-driving on harbour porpoises (Phocoena phocoena) at the first offshore wind farm in Germany
,”
Environ. Res. Lett.
8
,
025002
.
14.
Elliott
,
I. G.
,
Dawson
,
S. M.
, and
Rayment
,
W. J.
(
2012
). “
Optimizing T-pod settings and testing range of detection for bottlenose dolphins in Doubtful Sound, New Zealand
,”
J. Mar. Biol. Assoc. UK
92
,
1901
1907
.
15.
Elliott
,
R. G.
,
Dawson
,
S. M.
, and
Henderson
,
S.
(
2011
). “
Acoustic monitoring of habitat use by bottlenose dolphins in Doubtful Sound, New Zealand
,”
New Zeal. J. Mar. Freshw. Res.
45
,
637
649
.
16.
Gillespie
,
D.
,
Mellinger
,
D. K.
,
Gordon
,
J.
,
McLaren
,
D.
,
Redmond
,
P.
,
McHugh
,
R.
,
Trinder
,
P.
,
Deng
,
X.-Y.
, and
Thode
,
A.
(
2009
). “
PAMGUARD: Semiautomated, open source software for real-time acoustic detection and localisation of cetaceans
,”
J. Acoust. Soc. Am.
,
125
,
2547
–2547.
17.
Hardy
,
T.
,
Williams
,
R.
,
Caslake
,
R.
, and
Tregenza
,
N. J. C.
(
2012
). “
An investigation of acoustic deterrent devices to reduce cetacean bycatch in an inshore set net fishery
,”
J. Cetacean Res. Manag.
12
,
85
90
.
18.
Jones
,
G. J.
, and
Sayigh
,
L.
(
2002
). “
Geographic variation in rates of vocal production of free ranging bottlenose dolphins
,”
Mar. Mammal Sci.
18
,
374
393
.
19.
Leatherwood
,
S.
, and
Reeves
,
R. R.
(
1983
). “
Abundance of bottlenose dolphins in Corpus Christi Bay and coastal southern Texas
,”
Contrib. Mar. Sci.
26
,
179
199
.
20.
Leeney
,
R. H.
,
Berrow
,
S.
,
McGrath
,
D.
,
O'Brien
,
J.
,
Cosgrove
,
R.
, and
Godley
,
B. J.
(
2007
). “
Effects of pingers on the behaviour of bottlenose dolphins
,”
J. Mar. Biol. Assoc. UK
87
,
129
133
.
21.
Leeney
,
R. H.
,
Greaves
,
D.
,
Conley
,
D.
, and
O'Hagan
,
A. M.
(
2014
). “
Environmental impact assessments for wave energy developments—Learning from existing activities and informing future research priorities
,”
Ocean Coast. Manag.
99
,
14
22
.
22.
Mellinger
,
D.
,
Stafford
,
K.
,
Moore
,
S.
,
Dziak
,
R.
, and
Matsumoto
,
H.
(
2007
). “
An overview of fixed passive acoustic observation methods for cetaceans
,”
Oceanography
20
,
36
45
.
23.
Musial
,
W.
,
Beiter
,
P.
,
Schwabe
,
P.
,
Tian
,
T.
,
Stehly
,
T.
, and
Spitsen
,
P.
(
2016
). “
2016 Offshore Wind Technologies Market Report
,”
Report No. DOE/GO-102017-5031
, U.S. Dep. Energy, Washington, DC.
24.
Nowacek
,
D. P.
(
2005
). “
Acoustic ecology of foraging bottlenose dolphins (Tursiops truncatus), habitat-specific use of three sound types
,”
Mar. Mammal Sci.
21
,
587
602
.
25.
Nuuttila
,
H. K.
,
Courtene-Jones
,
W.
,
Baulch
,
S.
,
Simon
,
M.
, and
Evans
,
P. G. H.
(
2017
). “
Don't forget the porpoise: Acoustic monitoring reveals fine scale temporal variation between bottlenose dolphin and harbour porpoise in Cardigan Bay SAC
,”
Mar. Biol.
164
,
1
16
.
26.
Nuuttila
,
H. K.
,
Meier
,
R. M.
,
Evans
,
P. G. H.
,
Turner
,
J. R.
,
Bennell
,
J. D.
, and
Hiddink
,
J. G.
(
2013a
). “
Identifying foraging behaviour of wild bottlenose dolphins (Tursiops truncatus) and harbour porpoises (Phocoena phocoena) with static acoustic dataloggers
,”
Aquat. Mamm.
39
,
147
161
.
27.
Nuuttila
,
H. K.
,
Thomas
,
L.
,
Hiddink
,
J. G.
,
Meier
,
R.
,
Turner
,
J. R.
,
Bennell
,
J. D.
,
Tregenza
,
N. J. C.
, and
Evans
,
P. G. H.
(
2013b
). “
Acoustic detection probability of bottlenose dolphins, Tursiops truncatus, with static acoustic dataloggers in Cardigan Bay, Wales
,”
J. Acoust. Soc. Am.
134
,
2596
2609
.
28.
Philpott
,
E.
,
Englund
,
A.
,
Ingram
,
S.
, and
Rogan
,
E.
(
2007
). “
Using T-PODs to investigate the echolocation of coastal bottlenose dolphins
,”
J. Mar. Biol. Assoc. UK
87
,
11
17
.
29.
Pirotta
,
E.
,
Merchant
,
N. D.
,
Thompson
,
P. M.
,
Barton
,
T. R.
, and
Lusseau
,
D.
(
2015
). “
Quantifying the effect of boat disturbance on bottlenose dolphin foraging activity
,”
Biol. Conserv.
181
,
82
89
.
30.
Rankin
,
S.
,
Archer
,
F.
,
Keating
,
J. L.
,
Oswald
,
J. N.
,
Oswald
,
M.
,
Curtis
,
A.
, and
Barlow
,
J.
(
2017
). “
Acoustic classification of dolphins in the California Current using whistles, echolocation clicks, and burst pulses
,”
Mar. Mammal Sci.
33
,
520
540
.
31.
Robbins
,
J. R.
,
Brandecker
,
A.
,
Cronin
,
M.
,
Jessopp
,
M.
,
McAllen
,
R.
, and
Culloch
,
R.
(
2016
). “
Handling dolphin detections from C-PODs, with the development of acoustic parameters for verification and the exploration of species identification possibilities
,”
Bioacoustics
25
,
99
110
.
32.
Roberts
,
B. L.
, and
Read
,
A. J.
(
2014
). “
Field assessment of C-POD performance in detecting echolocation click trains of bottlenose dolphins (Tursiops truncatus)
,”
Mar. Mammal Sci.
31
,
169
190
.
33.
Roberts
,
J. J.
,
Best
,
B. D.
,
Mannocci
,
L.
,
Fujioka
,
E.
,
Halpin
,
P. N.
,
Palka
,
D. L.
,
Garrison
,
L. P.
,
Mullin
,
K. D.
,
Cole
,
T. V. N.
,
Khan
,
C. B.
,
McLellan
,
W. A.
,
Pabst
,
D. A.
, and
Lockhart
,
G. G.
(
2016
). “
Habitat-based cetacean density models for the US Atlantic and Gulf of Mexico
,”
Sci. Rep.
6
,
1
12
.
34.
Simard
,
P.
,
Hibbard
,
A. L.
,
McCallister
,
K. A.
,
Frankel
,
A. S.
,
Zeddies
,
D. G.
,
Sisson
,
G. M.
,
Gowans
,
S.
,
Forys
,
E. A.
, and
Mann
,
D. A.
(
2010
). “
Depth dependent variation of the echolocation pulse rate of bottlenose dolphins (Tursiops truncatus)
,”
J. Acoust. Soc. Am.
127
,
568
578
.
35.
Sousa-Lima
,
R. S.
,
Norris
,
T. F.
,
Oswald
,
J. N.
, and
Fernandes
,
D. P.
(
2013
). “
A review and inventory of fixed autonomous recorders for passive acoustic monitoring of marine mammals
,”
Aquat. Mamm.
39
,
23
53
.
36.
Teilmann
,
J.
, and
Carstensen
,
J.
(
2012
). “
Negative long term effects on harbour porpoises from a large scale offshore wind farm in the Baltic—Evidence of slow recovery
,”
Environ. Res. Lett.
7
,
045101
.
37.
Temple
,
A. J.
,
Tregenza
,
N.
,
Amir
,
O. A.
,
Jiddawi
,
N.
, and
Berggren
,
P.
(
2016
). “
Spatial and Temporal Variations in the Occurrence and Foraging Activity of Coastal Dolphins in Menai Bay, Zanzibar, Tanzania
,”
(D. Russo, Ed.) PLoS One
,
11
,
e0148995
.
38.
Thompson
,
P. M.
,
Brookes
,
K. L.
,
Graham
,
I. M.
,
Barton
,
T. R.
,
Needham
,
K.
,
Bradbury
,
G.
, and
Merchant
,
N. D.
(
2013
). “
Short-term disturbance by a commercial two-dimensional seismic survey does not lead to long-term displacement of harbour porpoises
,”
Proc. R. Soc. B Biol. Sci.
280
,
1
8
.
39.
Thompson
,
P. M.
,
Lusseau
,
D.
,
Barton
,
T.
,
Simmons
,
D.
,
Rusin
,
J.
, and
Bailey
,
H.
(
2010
). “
Assessing the responses of coastal cetaceans to the construction of offshore wind turbines
,”
Mar. Pollut. Bull.
60
,
1200
1208
.
40.
Toth
,
J. L.
,
Hohn
,
A. A.
,
Able
,
K. W.
, and
Gorgone
,
A. M.
(
2011
). “
Patterns of seasonal occurrence, distribution, and site fidelity of coastal bottlenose dolphins (Tursiops truncatus) in southern New Jersey, USA
,”
Mar. Mammal Sci.
27
,
94
110
.
41.
Tougaard
,
J.
,
Carstensen
,
J.
,
Teilmann
,
J.
,
Skov
,
H.
, and
Rasmussen
,
P.
(
2009
). “
Pile driving zone of responsiveness extends beyond 20 km for harbor porpoises (Phocoena phocoena (L.))
,”
J. Acoust. Soc. Am.
126
,
11
14
.
42.
Verfuß
,
U. K.
,
Honnef
,
C. G.
,
Meding
,
A.
,
Dähne
,
M.
,
Mundry
,
R.
, and
Benke
,
H.
(
2007
). “
Geographical and seasonal variation of harbour porpoise (Phocoena phocoena) presence in the German Baltic Sea revealed by passive acoustic monitoring
,”
J. Mar. Biol. Assoc. UK
87
,
165
176
.
43.
Wahlberg
,
M.
,
Jensen
,
F. H.
,
Aguilar Soto
,
N.
,
Beedholm
,
K.
,
Bejder
,
L.
,
Oliveira
,
C.
,
Rasmussen
,
M. S. M.
,
Villadsgaard
,
A.
, and
Madsen
,
P. T.
(
2011
). “
Source parameters of echolocation clicks from wild bottlenose dolphins (Tursiops aduncus and Tursiops truncatus)
,”
J. Acoust. Soc. Am.
130
,
2263
2274
.
44.
Wilson
,
B.
,
Thompson
,
P. M.
, and
Hammond
,
P. S.
(
1997
). “
Habitat use by bottlenose dolphins: Seasonal distribution and stratified movement patterns in the Moray Firth, Scotland
,”
J. Appl. Ecol.
34
,
1365
1374
.
45.
Yack
,
T.
,
Barlow
,
J.
,
Rankin
,
S.
, and
Gillespie
,
D.
(
2009
). “
Testing and validation of automated whistle and click detectors using PAMGUARD 1.0
,” NOAA Technical Memorandum National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Silver Spring, MD.
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