Use of chemical profiles in Use of chemical profiles in assessing the feeding ecology assessing the feeding ecology

of Alaska killer whalesof Alaska killer whales

Paul R. Wade | NOAA, National Marine Mammal LaboratoryPaul R. Wade | NOAA, National Marine Mammal LaboratoryCraig O. Matkin, Lance Barrett-Lennard – North Gulf Oceanic SocietyCraig O. Matkin, Lance Barrett-Lennard – North Gulf Oceanic Society

Richard G. LeDuc - NOAA, Southwest Fisheries Science CenterRichard G. LeDuc - NOAA, Southwest Fisheries Science Center

John W. Durban, Marilyn E. Dahlheim, Nancy Black – NOAA, National Marine Mammal Laboratory John W. Durban, Marilyn E. Dahlheim, Nancy Black – NOAA, National Marine Mammal Laboratory

David P. Herman, Douglas G. Burrows, Margaret M. Krahn – NOAA, Northwest Fisheries Science CenterDavid P. Herman, Douglas G. Burrows, Margaret M. Krahn – NOAA, Northwest Fisheries Science Center

2005 summary:

14 Transient groups (19 biopsies)

22 Resident groups (15 biopsies)

Use of chemical profiles in assessing the Use of chemical profiles in assessing the feeding ecology of eastern North Pacific killer feeding ecology of eastern North Pacific killer

whales whales

Krahn et al. submitted, Marine Environmental Krahn et al. submitted, Marine Environmental ResearchResearch

Qualitative comparison of “indicator” Qualitative comparison of “indicator” fatty acids—fish and marine fatty acids—fish and marine

mammalsmammals

Fish Marine mammals Offshores Residents Transients

Fatty AcidsSCMU

C14:1n5 L H 1.4 3.5 4.2C16:1n7 L H 19.621.4 27.1

Omega-3C22:6n3 H L 0.920.93 0.57

Relative proportions in fish compared to marine mammals

Proportions (wt%) in biopsy blubberfor each killer whale ecotype

On-going analyses of fatty acids of potential marine mammal prey

Separation of killer whale ecotypes Separation of killer whale ecotypes using DFA of Fatty Acids in blubberusing DFA of Fatty Acids in blubber

Separation of killer whale ecotypes Separation of killer whale ecotypes using DFA of PCBs in blubberusing DFA of PCBs in blubber

Carbon and nitrogen stable Carbon and nitrogen stable isotope ratios of killer whalesisotope ratios of killer whales

offshoreoffshore onshoreonshore

1 Trophic 1 Trophic LevelLevel

20

19

18

17

16

15

14

13

12

11

10

9

15

N

-21 -20 -19 -18 -17 -16 -15

13

C

belugawhale

bowheadwhale

finwhaleDall's

porpoise

graywhale

harborporpoise

humpbackwhale

minkewhale

harborseal

Pacficwalrus

northernfur seal

Stellersea lion

EAI/T(n=26)

CalculatedEAI/T Prey

Predicting the trophic level of Predicting the trophic level of killer whale preykiller whale prey

Matkin & Saulitis diet:Matkin & Saulitis diet:50% gray whale50% gray whale

29% northern fur seal29% northern fur seal14% minke whale14% minke whale7% Steller sea lion7% Steller sea lion

XX

NMML/NOAA diet:NMML/NOAA diet:18% gray whale18% gray whale

45% northern fur seal45% northern fur seal9% minke whale9% minke whale

9% Steller sea lion9% Steller sea lion18% Dall’s porpoise18% Dall’s porpoise

Use of contaminant ratios to identify Use of contaminant ratios to identify regional sourcesregional sources

• California Signature: ∑DDTs/∑PCBs– high ∑DDTS reflects heavy use of DDTs in California before

1970s ban • Asian signature: ∑HCHs/∑PCBs &

∑chlordanes/∑PCBs– high ∑HCHs or ∑chlordanes from pesticides used long

after the U.S. ban—ocean and air transport to Alaska• Asian signature of “new” DDT: p,p’-DDT/∑DDTs

– high p,p’-DDT reflects recent pesticide use of DDTs in Asia or Central America (low = “old” source in California)

• Alaska signature: low ∑DDTs/∑PCBs and high ∑chlordanes/∑PCBs – Presence of Asian signature and absence of California

signature

0 2 4 6 8

Calif ornia sea lion (n=7)

Northern fur seal (Alaska; n=16)

Gray whale juveniles (North Pacific; n=17)

Harbor seal (Alaska; n=4)

Steller sea lion pups (Alaska; n=4)

Chinook (Cook I nlet, Alaska; n=3)

Chinook (Calif ornia; n=29)

West coast transients (Calif ornia; n=4)

Eastern Aleutian I sland transients (n=15)

Central Aleutian I sland residents (n=3)

Eastern Aleutian I sland residents (n=20)

Gulf of Alaska residents (n=17)

Off shores (n=4)

DDTs/PCBs

Possible prey

Killer whales

Ratio of DDT to PCBRatio of DDT to PCB

California signature

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6

Calif ornia sea lion (n=7)

Northern fur seal (Alaska; n=16)

Gray whale juveniles (North Pacific; n=17)

Harbor seal (Alaska; n=4)

Steller sea lion pups (Alaska; n=4)

Chinook (Cook I nlet, Alaska; n=3)

Chinook (Calif ornia; n=29)

West coast transients (Calif ornia; n=4)

Eastern Aleutian I sland transients (n=15)

Central Aleutian I sland residents (n=3)

Eastern Aleutian I sland residents (n=20)

Gulf of Alaska residents (n=17)

Off shores (n=4)

chlordanes/ PCBs

Possible prey

Killer whales

Ratio of Ratio of chlordanes/chlordanes/PCBsPCBs

Asian signature

““New” DDT (from Asia)New” DDT (from Asia)High ratio = recent sourceHigh ratio = recent source

0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16

Calif ornia sea lion (n=7)

Northern f ur seal (Alaska; n=16)

Gray whale juveniles (North Pacific; n=17)

Harbor seal (Alaska; n=4)

Steller sea lion pups (Alaska; n=4)

Chinook (Cook I nlet, Alaska; n=3)

Chinook (Calif ornia; n=29)

West coast transients (Calif ornia; n=4)

Eastern Aleutian I sland transients (n=15)

Central Aleutian I sland residents (n=3)

Eastern Aleutian I sland residents (n=20)

Gulf of Alaska residents (n=17)

Off shores (n=4)

p,p'-DDT/ DDTs

Possible prey

Killer whales

Concentration of PBDEs (flame Concentration of PBDEs (flame retardant) retardant)

0 1000 2000 3000 4000 5000

Central Aleutian Residents

Eastern Aleutians Residents

Gulf of Alaska Residents

Offshores

Eastern Aleutian transients

West Coast transients

Eastern tropical Pacific

∑ PBDEs

12,600

Ratio of PBDEs to PCBsRatio of PBDEs to PCBs

0.00 0.05 0.10 0.15 0.20 0.25 0.30

Calif ornia sea lion (n=7)

Northern f ur seal (Alaska; n=0)

Gray whale juveniles (North Pacific; n=0)

Harbor seal (Alaska; n=0)

Steller sea lion pups (Alaska; n=3)

Chinook (Cook I nlet, Alaska; n=0)

Chinook (Calif ornia; n=27)

West coast transients (Calif ornia; n=10*)

Eastern Aleutian I sland transients (n=15)

Central Aleutian I sland residents (n=3)

Eastern Aleutian I sland residents (n=20)

Gulf of Alaska residents (n=17)

Off shores (n=4)

PBDEs/ PCBs

Possible prey

Killer whales

California signature

ConclusionsConclusions

• Offshore killer whales consume a diet that is Offshore killer whales consume a diet that is clearly distinct from those of residents and clearly distinct from those of residents and transientstransients

• Offshore killer whales biopsied in Alaska feed at Offshore killer whales biopsied in Alaska feed at least part of the year in California, presumably on least part of the year in California, presumably on highly contaminated, high trophic level marine fish highly contaminated, high trophic level marine fish (not fur seals as earlier hypothesized)(not fur seals as earlier hypothesized)

• Resident and transient killer whales in Alaska have Resident and transient killer whales in Alaska have contaminant ratios that appear to reflect the area contaminant ratios that appear to reflect the area where they are sampled in spring/summer (e.g., where they are sampled in spring/summer (e.g., suggests they do not make large scale suggests they do not make large scale movements in fall/winter to other regions, unlike movements in fall/winter to other regions, unlike offshore whales) offshore whales)

ConclusionsConclusions

• Resident killer whales in Alaska exhibit a gradient Resident killer whales in Alaska exhibit a gradient in chemical profiles from west (central Aleutians) in chemical profiles from west (central Aleutians) to east (Gulf of Alaska) that likely represents a shift to east (Gulf of Alaska) that likely represents a shift from off-shelf to continental shelf-based prey and from off-shelf to continental shelf-based prey and lower to higher trophic level. lower to higher trophic level.

– This supports the hypothesis that diets of EAI/R and GOA/R This supports the hypothesis that diets of EAI/R and GOA/R whales whales contain a high proportion of salmon, whereas the contain a high proportion of salmon, whereas the diet of thediet of the CAI/R whales CAI/R whales may include lower trophic level, may include lower trophic level, demersal preydemersal prey..

• Eastern Aleutian transients do not have a Eastern Aleutian transients do not have a spring/summer diet that is composed exclusively of spring/summer diet that is composed exclusively of Steller sea lions, because stable isotope ratios Steller sea lions, because stable isotope ratios show that their diet must include lower trophic show that their diet must include lower trophic level species to offset the high tropic level of the level species to offset the high tropic level of the sea lions. sea lions.

AcknowledgmentsAcknowledgments

• Funding support Funding support – North Pacific Research BoardNorth Pacific Research Board– L. Jones of the NWFSC Marine Mammal ProgramL. Jones of the NWFSC Marine Mammal Program– T. K. Rowles T. K. Rowles of of the Marine Mammal Health and Stranding the Marine Mammal Health and Stranding

Response Program of NOAA FisheriesResponse Program of NOAA Fisheries• Sample and data analysis Sample and data analysis

– D. W. Brown, G. M. Ylitalo, C. A. Sloan, R. H. Boyer, R. W. D. W. Brown, G. M. Ylitalo, C. A. Sloan, R. H. Boyer, R. W. Pearce and J. L. BoltonPearce and J. L. Bolton

• Killer whale biopsy samplesKiller whale biopsy samples– R. L. Pitman and the Southwest Fisheries Science Center R. L. Pitman and the Southwest Fisheries Science Center

provided biopsy samples (Z38169, Z38170, Z38171 and provided biopsy samples (Z38169, Z38170, Z38171 and Z38175)Z38175)

– Nancy Black of the Monterey Bay Whale Watch provided Nancy Black of the Monterey Bay Whale Watch provided samples of the West Coast (California) killer whalessamples of the West Coast (California) killer whales

• Killer whale prey data Killer whale prey data – G. M. Ylitalo, S. O’Neill, J. West and J. Buzitis for Chinook G. M. Ylitalo, S. O’Neill, J. West and J. Buzitis for Chinook

salmon salmon – Kimberlee Beckmen for Steller sea lion Kimberlee Beckmen for Steller sea lion