killer whales do it in the dark: nocturnal activity by transients at st. paul island kelly newman...
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Killer Whales Do It In The Killer Whales Do It In The Dark: Nocturnal Activity By Dark: Nocturnal Activity By Transients At St. Paul IslandTransients At St. Paul Island
Killer Whales Do It In The Killer Whales Do It In The Dark: Nocturnal Activity By Dark: Nocturnal Activity By Transients At St. Paul IslandTransients At St. Paul Island
Kelly Newman Kelly Newman Alan SpringerAlan Springer
University of Alaska FairbanksUniversity of Alaska FairbanksSchool of Fisheries and Ocean SciencesSchool of Fisheries and Ocean Sciences
Kelly Newman Kelly Newman Alan SpringerAlan Springer
University of Alaska FairbanksUniversity of Alaska FairbanksSchool of Fisheries and Ocean SciencesSchool of Fisheries and Ocean Sciences
Photo: Bob Pittman
Why Study Killer Whales at St. Paul?
•Pinniped and sea otter collapses in Alaska•Fur seals declining on Pribilofs•Predation as a factor in population dynamics•St. Paul is a predation hot-spot
Problem of documentation
ExpensiveTime consumingLow probability of observing predationPoor field conditions
SolutionsSolutions
Work in predation hot-spots Use alternative techniques Acoustic monitoring
8x more effective than just visual for detecting marine mammals
Work in predation hot-spots Use alternative techniques Acoustic monitoring
8x more effective than just visual for detecting marine mammals
FUR SEAL ROOKERIES
From NMML website
Accepted TheoryAccepted Theory
Transients use stealth to hunt–quieter before kills
Transient killer whales are most vocal when feeding
Calling behavior can indicate feeding activity
Transients use stealth to hunt–quieter before kills
Transient killer whales are most vocal when feeding
Calling behavior can indicate feeding activity
Recording MethodsRecording Methods “Pop Up” Autonomous Recording Unit Continuous recording June 22-July 12,
2006 Frequency Range 0.5-16,000 Hz
“Pop Up” Autonomous Recording Unit Continuous recording June 22-July 12,
2006 Frequency Range 0.5-16,000 Hz
AnalysisAnalysis
Raven 1.3 Sound Analysis Software 512 point spectrograms were
visually and aurally inspected for killer whale calls and whistles
Sound files were fifteen minutes
Raven 1.3 Sound Analysis Software 512 point spectrograms were
visually and aurally inspected for killer whale calls and whistles
Sound files were fifteen minutes
Call DetectionCall Detection
Number of days recorded 22
Number of 24 days analyzed 20
Number of days killer whales detected
19
Number of hours analyzed 480
Number of 15 minute recording segments killer whales were detected
190 out of 1920
ResultsResults
0
2
4
6
8
10
12
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Nu
mb
er o
f d
ays
wit
h c
alls
in
eac
h h
ou
r
0
5
10
15
20
25
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Alaska Daylight Time
Nu
mb
er
of
15
min
ute
in
terv
als
w
ith
ca
lls
Killer Whale Vocal Frequency Over 24 hours
CT SR
CT SR
SS CT
SS CT
ST
Nu
mb
er o
f days w
ith
calls
Dete
ctio
ns
1 2 3
0
2
4
6
time
vox
More activity from midnight through morning
Kille
r Wh
ale
D
ete
ctio
ns
Time of Day P value<.0001
0000 through 0745 0800 through 1545 1600 through 2345
From Jeremy Sterling
Sunset Sunrise
Fur Seal Departure Times
KnownKnown
Only transients identified at St. Paul They have only been observed
eating fur seals at the islands Considered a “problem” in the past
Only transients identified at St. Paul They have only been observed
eating fur seals at the islands Considered a “problem” in the past
Abundance Persistence Group structure Predation rates
Abundance Persistence Group structure Predation rates
UnknownUnknown
From Heather Vukelic
ConclusionsConclusions St Paul is frequented by killer
whales on a daily basis Only transients have been
identified Potential predation rates can be
monitored at this hot-spot This is only one feeding area in the
Pribilof Islands
St Paul is frequented by killer whales on a daily basis
Only transients have been identified
Potential predation rates can be monitored at this hot-spot
This is only one feeding area in the Pribilof Islands
ImplicationsImplications
The observation window for killer whale activity needs to be expanded to include nocturnal activity.
Quantification of their ecological role is meaningless with limited observation power.
The observation window for killer whale activity needs to be expanded to include nocturnal activity.
Quantification of their ecological role is meaningless with limited observation power.
Phase II
Identify call typesCorrelate with visual observationsAcoustically “map” the Pribilof Islands for killer whale activity
AcknowledgementsAcknowledgements
Alaska Sea Grant John Melovidov and Crew of the
MarySea Greenpeace Jacob Merculief NPRB (COFFS)
Alaska Sea Grant John Melovidov and Crew of the
MarySea Greenpeace Jacob Merculief NPRB (COFFS)