Polar Bear Hair Snare Project
| North Slope Borough Contact | Jason Herreman, Todd Sformo, Andy Von Duyke |
| Collaborators | USGS |
| Funding | NSB, USGS |
Project Description:
This project will use hair snares setup around bowhead whale carcasses including beach cast and “bonepiles” created from harvested animals to look at the importance of bowhead carcass use by polar bears (Ursus maritimus). DNA collected from the hair samples will be included in and referenced against the current USGS polar bear genetics data base.
Objectives:
1. Genetically identify bears that use bowhead whale carcasses through hair snares and microsatellite DNA.
2. Document annual and seasonal use cycles of bowhead carcasses by individual bears.
3. Determine relatedness of individuals that use carcasses.
4. Determine if visitation rates are high enough to make population estimates using mark recapture feasible.
5. Compare use of bone piles to beach cast whales by polar bears.
6. Compare the proportion of previously marked bears, from the USGS mark recapture program, sampled to the estimated total proportion of marked bears in the entire population.
Methods:
Barbed wire fence hair snares will be erected around bowhead carcasses by North Slope Borough (NSB) biologists. Snares will be checked regularly by local biologists or technicians to collect samples (this could mean as often as once a day during busy periods). Currently identified collection sites include the Barrow and Kaktovik bone piles. Other sites will be identified as carcasses wash up. Samples will be sent to the USGS’s lab of choice for genotyping. Genotype analysis will be carried out by NSB and/or USGS biologists. Results from this project will be presented to the communities involved by NSB biologists. Joint publications will be produced by cooperating agencies.
Hair snare sampling protocol:
A single strand of barbwire attached to t-posts will be erected around bone piles or carcasses to collect hair. The fence will be set at a height to avoid collection of fox hairs (above 0.3 m). Multiple samples will only be collected if snared hair is greater than the width of a single bear (0.75-1m). To avoid mixed sample collections, barbs packed full of hair will not be used for collection unless video proves that only a single bear crossed that line of barbs since the last sampling. Cameras will be set up to monitor effectiveness of snares so that adjustments can be made if needed. All unsampled hair will be removed from snares each time they are checked. Snares will be checked regularly starting with every other day and adjusting as needed by use. The heaviest use is likely to occur right after fall whaling before the return of ice. Samples will be stored in manila paper envelopes and kept frozen until analysis.
- Fence posts spacing: approximately 10 meters.
- Fence height: 0.5 meters.
- Spacing between samplings: 0.75 meters.
- Check frequency: Every other day, adjusted as needed.
Contributing partners:
NSB: field work, analysis, writing, reviewing, in-kind personnel contributions, sample collection funding.
USGS: sample archive, analysis, writing, reviewing, funding for sample analysis.
This project is a two phase study. The first two years will be a pilot study. Year one will occur in the Barrow area only. In year two, we will hopefully expand to additional sites in the Kaktovik area. Years three through five will be a continuation of the pilot study carried out in both villages as funding allows.
Proposed project Start Date: 9/1/10
Proposed project End Date: 9/1/15
Project Update 22 November 2010:
The polar bear hair snare fence has been set up at the bonepile near Point Barrow since early November. The fence was checked daily for the first 4 days and has been checked every other day since (except during blizzards!). Hundreds of hair samples have already been collected. These samples will be sent to a lab at a later date for genetic analysis.
Billy Adams and Harry Brower, Jr., after setting up hair snare fence. Photo: Jason Herreman
Project Update June 2011:
We have been highly successful at collecting samples. So far, 649 hair samples have been collected (as of May 27, 2011). There is no evidence of injury to bears despite the occurrence of scuffles, startling events, and numerous bears using the pile at one time (up to 20 bears) as seen on the video camera. The fence requires periodic maintenance as bears move over or under it. Here are some pictures of bears crossing the fence.
Polar bear moving over the Hair Snare fence
This graph shows the number of hair samples collected from the Hair Snare fence from November 2010 to May 2011
Time of day most bears present:
- Fall/Winter: bears appear to use bonepile at all hours as long as humans are not present. Likely due to limited light.
- Spring: majority of bears use bone pile during early morning or late evening (exception seems to be large adult males).
Preliminary results from hair analyses:
The 200 samples from the first 3 months of collection were sent in for analysis in February 2011 (currently the highest period of harvest in Barrow). And, 97 individuals have been identified (showing a 35% recapture rate). Seventy-five (75 or 77%) of the bears were not currently identified in the USGS genetics database. There was a 17% failure rate of hair samples providing DNA for analysis (most underfur hair). No fresh beached marine mammal carcasses since study began. Unable to compare carcass use to bone pile use.
Future plans:
- Expand sampling to 2 additional sites: Cooper Island guillemot colony and Kaktovik bone pile.
- Adjust sample and analysis schemes to maximize new individuals.
Publications:
- Herreman, J., E. Peacock. 2011. Non-invasive genetic sampling of polar bears (Ursus maritimus). Poster presentation to International Association for Bear Research and Management Conference.
- Poster – July 2011.
