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Predation on Northern Fur Seals In The Pribilof Islands: A Baseline Study

Predation on Northern Fur Seals In The Pribilof Islands: A Baseline Study. Andrew Malavansky 1 , Aquilina D. Lestenkof 2 , Desiree Lekanof 1 , Michael C. Brewer 2 , Kate M. Wynne 3 , Amanda M. Merklein 4 , and Bruce W. Robson 4. Traditional Knowledge Survey and Local Fishery Logbook Program.

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Predation on Northern Fur Seals In The Pribilof Islands: A Baseline Study

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  1. Predation on Northern Fur Seals In The Pribilof Islands: A Baseline Study Andrew Malavansky1, Aquilina D. Lestenkof2, Desiree Lekanof1, Michael C. Brewer2, Kate M. Wynne3, Amanda M. Merklein4, and Bruce W. Robson4 Traditional Knowledge Survey and Local Fishery Logbook Program 1St. George Traditional Council, Kayumixtax Eco-Office 2Aleut Community of St. Paul Island-Tribal Government, Ecosystem Conservation Office 3School of Fisheries and Ocean Sciences, University of Alaska Fairbanks 4Community and Ecology Resources

  2. Study Design • Baseline information about predation on fur seals around the Pribilof Islands. • Community-based approach: local fishermen and residents with a year-round presence on the islands • Two methods: • Fishery logbook program • Local and Traditional Knowledge (LTK) survey. • Trends in the location, numbers and seasonality of killer whale observations and Steller sea lion predation • Nature and extent of marine mammal/fisheries interactions

  3. Methods – Fisheries Logbook • Compact, water-proof logbook • Standardized format • Location, date, time and other relevant information for killer whale sightings and predation observations. • Additional observations of interest recorded • Fishermen were contacted regularly in dockside surveys

  4. Logbook Example

  5. Methods – LTK Interviews • Interview Subjects • local and non-resident fishermen • subsistence hunters • community residents and elders • Standardized survey instrument • Target Information: • Spatial and temporal occurrence of killer whales • Predation events • Photographic documentation • Fisheries interactions • Observations spatially referenced to a lat/lon grid for GIS analysis

  6. Results – Fisheries Logbooks • 15 boats from St. Paul and 3 from St. George • Mid-June through late-September • 17 sightings of KW in logbooks • 4 KW sightings in dockside and LTK interviews • Near-shore waters and shelf break • No predation events reported by fishermen in 2006 • Other species observed: fin whales, minke whales, northern fur seals, short-tailed albatross, ancient murrlets, and coho salmon

  7. Killer Whale Encounters

  8. Results – LTK Interviews • Forty-nine LTK interviews ( July to November of 2006). • 87 killer whale observations 1976 – 2006 • 76% were from 2000 or later • 48 on St. Paul • 39 St. George • 17 from the Island Sentinel Programs (St. George n=2; St. Paul n=15). • 26 sightings of killer whales during 2006 May - November

  9. LTK Distribution • The highest percentage of observations on each island occurred in the Lat/Lon grid cells surrounding the villages.

  10. Group Size • LTK (2000-06) • 2.9 at St. George Island (n=16) • 3.3 at St. Paul Island (n=53) • 16.0 for off-shore sightings (n=4) • Logbooks – 2006 • 3.7 whales per encounter

  11. Photo 3. Documentation of a killer whale predation event. Photographs taken by local fisherman Phillip Lestenkof during the 2004 halibut fishery off St. Paul Island. Photo 3. Documentation of a killer whale predation event. Photographs taken by local fisherman Phillip Lestenkof during the 2004 halibut fishery off St. Paul Island. Photo 3. Documentation of a killer whale predation event. Photographs taken by local fisherman Phillip Lestenkof during the 2004 halibut fishery off St. Paul Island. Predation • No predation observed by local fishermen in 2006 • Last observation by a St. Paul Island fishing vessel was in 2004 • LTK predation events 1981-2006 • 9 Killer whale events • 7 Steller sea lions events • Two observations of SSL feeding on fur seal pups in 2006 on St. George Island. • No observations of SSL feeding on fur seals reported on St. Paul Island.

  12. Additional Observations • LTK: fin whales minke whales, gray whales, humpback whales, sperm whales, unidentified large whales, dall’s porpoise, and sharks. • Logbooks: fin whales, minke whales, northern fur seals, short-tailed albatross, ancient murrlets, and coho salmon.

  13. Summary Observations No gear interaction between killer whales and halibut fishery near shore, only at shelf break Small killer whale group sizes near islands No predation by sea lions on fur seal pups at St. Paul, only St. George

  14. Acknowledgements We gratefully acknowledge the support and participation of the communities of St. Paul and St. George Island. This research could not have been conducted without the help and cooperation of local fishermen and the CBSFA and APICDA. This study was funded under UAF/PCCRC Grant 06-0036 to the St. George Traditional Council.

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