1. Killer Whales Do It In The Dark: Nocturnal Activity By Transients At St. Paul Island
Kelly Newman
Alan Springer
University of Alaska Fairbanks
School of Fisheries and Ocean Sciences
Hello. I will be talking about the results of a pilot study we did last summer Acknowledge Alan Springer
Photo: Bob Pittman

2. 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

3. Problem of documentation
Expensive
Time consuming
Low probability of observing predation
Poor field conditions

4. Solutions Work in predation hot-spots Use alternative techniques
Acoustic monitoring
8x more effective than just visual
for detecting marine mammals

5. FUR SEAL ROOKERIES From NMML website
Pribs as a whole support the largest worldwide populations. Pribilofss have over fifty seven % of the worlds pop. Other studies being conducted concurrently show that the NFS at reef will forage to the west.
From NMML website

6. Accepted Theory Transients use stealth to hunt–quieter before kills
Transient killer whales are most vocal when feeding
Calling behavior can indicate feeding activity

7. Recording Methods “Pop Up” Autonomous Recording Unit
Continuous recording June 22-July 12, 2006
Frequency Range ,000 Hz

8. Analysis 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

9. Call Detection

10. Results 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
22 days recorded. Two of those were partial days. On Twenty days were the POP UP recorded for 24 hours.

11. Killer Whale Vocal Frequency Over 24 hours
Number of days with calls
Killer Whale Vocal Frequency Over 24 hours
CT SR ST
SS CT
Here is a 24 hour break down of the calling activity. Here is Zero and here is Please note the abundance of calls from zero am throughout the night. Here we have the numThere is a lull mid day, then more activity around What is about Nocturnal in Alaska? in relation to civil twilight, mid to mid…sunset is at Note after sunset is when the calls are detected more. TAKE HOME see how much is going on in the middle of the night?
Detections
CT SR
SS CT

12. More activity from midnight through morning
Killer Whale Detections
If you break up the day into t, you If three time frames, the number of detections are significantly different throughout the day. With more happening from midnight thru 800 am.The period of
0000 through through through 2345
Time of Day
P value<.0001

13. Fur Seal Departure Times
This graph demonstrates the movements of NFS throughout the 24 day. The Black bars are the number of seals departing rookeries at St Paul Island. The NFS are departing the rookeries more at sunset. The line indicates pooled sunset times over an entire breeding season, and the dashed lines are
Sunset Sunrise
From Jeremy Sterling

14. Known 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 are confirmed. Not only recent years.. there is some evidence that orcas were considered a nuisance I the past.

15. Unknown Abundance Persistence Group structure Predation rates
So what we do not know is the population structure of killer whales at St Paul. Nor do we know the persistance of the various groups. This type of work can get at these questions because killer whale ecotypes can be identified by their vocalizations.
From Heather Vukelic

16. Conclusions 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
It is important to recognize that the use of acoustics was the only way t get at this comprehensive picture.

17. Implications
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.

18. Phase II Identify call types Correlate with visual observations
Acoustically “map” the Pribilof Islands for killer whale activity
Killer whale groups can be identied by call type. The next step is to correlate with visual observations. There were some but is is noteworthty how much was going on without visuall observations.

19. Acknowledgements Alaska Sea Grant
John Melovidov and Crew of the MarySea
Greenpeace
Jacob Merculief
NPRB (COFFS)
AK Sea Grant fo paying for this study. Several boats whoe helped us with deploying and retrieving the pop up, as well as for surveying the area.