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1 Craig Matkin Lance Barrett Lennard David Ellifrit Ecotypic Variation and Predatory Behavior of Killer Whales in the Eastern Aleutians ASLC NPUMMRC.

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Presentation on theme: "1 Craig Matkin Lance Barrett Lennard David Ellifrit Ecotypic Variation and Predatory Behavior of Killer Whales in the Eastern Aleutians ASLC NPUMMRC."— Presentation transcript:

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2 1 Craig Matkin Lance Barrett Lennard David Ellifrit Ecotypic Variation and Predatory Behavior of Killer Whales in the Eastern Aleutians ASLC NPUMMRC

3 Acknowledgements SSLRI Steller Sea Lion Research Initiative Field Assistance: Mike Brittain Damian Power, Peter Nilsson, Buck Laukitis Flip Nicklin (photographs) NPUMMRC Alaska Sea Life Center

4 Southeastern Alaska Northern Gulf of Alaska Eastern Aleutians Bering Sea Regional focal areas and “hotspots” as a Complement to NMFS/NMML cruisesMethods

5 Summer Spring

6 Research vessels: ‘ aluminum fishing boats aluminum fishing boats

7 PHOTOIDENTIFICATION OF INDIVIDUALS over a period of years from small vessels in killer whale “hot spots” High speed Black and white With digital backup

8 GENETICS, CONTAMINANTS, LIPID/FATTY ACID, STABLE ISOTOPES Using an air powered rifle to to collect skin and blubber biopsies

9 Lightweight biopsy darts take a 30mm x 5mm sample from saddle patch region

10 Biopsy darts with samples

11 ACOUSTICS Classification of Discrete Calls to Determine Lineage

12 FEEDING HABITS Direct evidence required to determine predation 1)Sample of prey 2)Prey observed in mouth

13 Separation of Lineages by Genetics, Acoustics and Association All groups of whales from 281 killer whale encounters from 2001 to 2005 could be classified to lineages by acoustic or genetic sampling or association with previously sampled animals Three lineages were determined: RESIDENTSRESIDENTS (900+), TRANSIENTSTRANSIENTS (192) OFFSHORESOFFSHORES (54+) only one encounter

14 RESIDENTS 31 calls identified, 23 call types. Seven showed no similarity with residents in other areas, 16 shared some structural similarity with residents from GOARESIDENTS 31 calls identified, 23 call types. Seven showed no similarity with residents in other areas, 16 shared some structural similarity with residents from GOA TRANSIENTS No calls shared with residents. Identified 24 calls and 14 call types. Seven showed no similarity to transients in other areasTRANSIENTS No calls shared with residents. Identified 24 calls and 14 call types. Seven showed no similarity to transients in other areas OFFSHORES No shared calls with transients/residents Recordings from only one encounter, but very similar to calls recorded in offshore encounters elsewhereOFFSHORES No shared calls with transients/residents Recordings from only one encounter, but very similar to calls recorded in offshore encounters elsewhere There is with residents and transients evidence for finer scale population separations, but not with offshoresThere is with residents and transients evidence for finer scale population separations, but not with offshores Acoustic Separations

15 Genetic mtDNA Separations RESIDENTSRESIDENTS Single haplotype =NR ( central Aleutians = SR (NMML data) northern Gulf of AK = NR/SR mix) TRANSIENTSTRANSIENTS False Pass (spring) mixed haplotypes = GAT1, GAT2, AT1 Unimak Pass/Umnak I. (summer)= Single haplotype = GAT1 OFFSHORESOFFSHORES = Single Haplotype = OFF

16 Ecotypic Separation Research results thus far indicate Eastern Aleutian resident lineages and transient lineages comprise separate ecotypes… residents preying on fish and transients on marine mammals Data is insufficient to classify offshore lineages by ecotype

17 Resident Killer Whale Tracklines Tracks tend to follow 200m depth contour

18 Discovery Curve for Eastern Aleutian Resident Killer Whales

19 False Pass Spring EA Summer Number of Transients Identified in Eastern Aleutians

20 Spring False Pass Summer Eastern Aleutians Discovery Curves for Spring False Pass and Summer Eastern Aleutians Transients Summer 2005: short season

21 Eastern Aleutian Transient Predation

22 From Barrett-Lennard and Matkin in review Also harassment: 2 northern fur seals 3 Dalls porpoise 1 Humpback whale

23 From Barrett-Lennard and Matkin in prep

24 AT 1 n=38 PWS and KF SEA n =90 Transient Feeding Summary (Kills Only observed by researchers only) researchers only) EAT summer N=9 Also see John Maniscalco et al poster

25 Northern Fur Seal Gray Whale In May-June, 75+ individuals from a total “population” of 141+ transient killer whales focus on grey whales in False Pass/Unimak Island area In summer, 20+ individuals of a total “population” of 63+ transient killer whales feed primarily on Northern fur seals from Unimak Pass to Umnak Island

26 Conclusions Only transient type whales are significant marine mammal predators in the Eastern AleutiansOnly transient type whales are significant marine mammal predators in the Eastern Aleutians Prey and predatory behavior of killer whales varies by location and season in EA. Across Alaska there is a wide variation in predatory behaviorPrey and predatory behavior of killer whales varies by location and season in EA. Across Alaska there is a wide variation in predatory behavior Fur seals are preferred summer prey. Impact on this locally increasing population?Fur seals are preferred summer prey. Impact on this locally increasing population? If SSL predation was at similar levels in the past, it is unlikely that it drove the decline.If SSL predation was at similar levels in the past, it is unlikely that it drove the decline. But fur seals were not as abundant in the past, SSL may have been more important in the diet.But fur seals were not as abundant in the past, SSL may have been more important in the diet. Suprisingly, frequent predation on minke whales; however, little evidence of predation on HW even though they are much more abundantSuprisingly, frequent predation on minke whales; however, little evidence of predation on HW even though they are much more abundant

27 Bogoslof Island Steller Sea Lion Rookery Pups Northern Fur Seal Rookery Pups , ,631

28 Future Work Examine predation in more detail in summer in Bogoslof Is / Bishop Point.(sea lion haulout) and continue spring work in False Pass/Unimak Island.Examine predation in more detail in summer in Bogoslof Is / Bishop Point.(sea lion haulout) and continue spring work in False Pass/Unimak Island. Transient KW population dynamics in False PassTransient KW population dynamics in False Pass Radio/Satellite Tagging to increase follow times and determine long term movements of KW in relation to potential preyRadio/Satellite Tagging to increase follow times and determine long term movements of KW in relation to potential prey Nuclear DNA analysis/ further acoustic analysis to determine killer whale fine population structure in EANuclear DNA analysis/ further acoustic analysis to determine killer whale fine population structure in EA Continue research into chemical methods of assessing predation jointly with NWFSC and NMMLContinue research into chemical methods of assessing predation jointly with NWFSC and NMML

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