ACCESS NUMBER: TO-15180

STUDY TITLE: Timing and re-interpretation of ringed seal surveys

REPORT TITLE: Timing and re-interpretation of ringed seal surveys

CONTRACT NUMBER: OCS Study MMS 2006-013; TASK ORDER (TO): 15180

SPONSORING OCS REGION: Alaska

APPLICABLE PLANNING AREA: Beaufot-t Sea

FISCAL YEAR OF PROJECT FUNDING: 2003

COMPLETION DATE OF REPORT: September 2006

COST: FY2003: $232921; CUMULATIVE PROJECT COST: $685,470

PROJECT MANAGER: Brendan P. Kelly

AFFILIATION: University of Alaska Southeast

ADDRESS: School of Arts and Sciences, University of Alaska Southeast, Juneau, AK 99801

PRINCIPAL INVESTIGATOR: Brendan P. Kelly

KEY WORDS: Marine mammals, seals, surveys, landfast ice zone, nearshore Beaufort Sea

BACKGROUND:

Inter-annual and spatial comparisons of ringed seal (Phoca hispida) densities based on aerial surveys have not adequately accounted for the proportion of seals concealed within subnivean lairs. Previous models of the factors influencing the density of seals detected in aerial surveys have been based on densities observed during surveys conducted under limited ranges of conditions. We used the probability of radio tagged seals being visible as our response variable to determine which environmental factors were most important in explaining the availability of seals to be counted.

OBJECTIVES:

Our objectives were to:

Determine the relationship between environmental variables (including snow conditions) and the number of seals visible during spring surveys.

Determine the best methods for monitoring snow conditions and determining optimal survey times,

Reanalyze previous ringed seal surveys from the Beaufort Sea of Alaska.

DESCRIPTION:

We used VHF radio telemetry to estimate

surface during the spring months in 1999.

of radio tagged seals being visible as our

factors were most important in explaining

SIGNIFICANT CONCLUSIONS:

Changes in the number of seals counted during ground-based, visual surveys of seals resting on the ice corresponded to changes in the number of radio-tagged seals basking. Tagged seals spent 16% (SD 10%) of their time out of the water while using subnivean lairs and 55% (SD = 22%) of their time out of water after emerging from those lairs. Emergence from the lairs was

the proportion of ringed seals visible resting on the ice 2000, 2001, 2002, and 2003. We used the probability

response variable to determine which environmental

the availability of seals to be counted.
related to structural failure of the snow pack and passive microwave emissions - indicative of liquid moisture in the snow - predicted lair abandonment (r2 0.982, p = 0.001). Active microwave (Ku-band) backscatter also detected snow meh

event. but responded to an anomalous rain

Radio-tagged ringed seals remained close to their capture and release sites in April, May and early June. The mean home range size (based on breathing holes and lairs visited by tagged seals) during the breeding season was 1.73 km2 (SD = 4.19), and 94% of the home ranges were less than 3 km2. Inter-annual fidelity to breeding sites was observed in 3 adult ringed seals males and 1 female) and (2 suggests fitness costs to displacement of population structuring. of seals and an unexpected level

STUDY RESULTS:

The most important variables influencing the fraction of day, date, wind speed, air seals available to be counted were time of temperature, and days from snow melt as determined by passive microwave emissions. Modeling of the probability that seals were visible during past aerial surveys indicated that the fraction of seals visible varied from less than 0.40 to more than 0.75 between survey years, Future surveys should be conducted after seals have emerged from their lairs and should employ telemetry to determine the probability that seals are visible.

STUDY PRODUCTS:

VENUE DATE PRESENTER

Univ. Alaska Southeast, Juneau

Coastal Marine Institute, Fairbanks

Coastal Marine Institute, Fairbanks

Research Experiences for Undergrads, Univ. Alaska Southeast, Juneau

Am. Soc. Limnology & Oceanography,

Albuquerque, N.M.

Coastal Marine Institute, Fairbanks

Biomonitoring/Global Change, Ascona, Switzerland

MMS Information Transfer, Anchorage Apr. 2001

U.S-Russia Marine Mammal Project, Santa Apr. 2001 Cruz, CA

Mt. Film Festival, Telluride, CO May 2001

Biennial Coof. Biol. Marine Mammals, Dec. 2001 Vancouver, B.C.

Coastal Marine Institute, Fairbanks Feb. 2003

MMS Information Transfer, Anchorage Apr. 2003

NatI. Academy of Science, Anchorage Mar. 2003

MMS Scientific Committee, Anchorage Apr. 2003

Research Experiences for Undergrads, Aug. 2003 Univ. Alaska Southeast, Juneau

Research Experiences for Undergrads, Univ. Alaska Southeast, Juneau S4 Arctic Science Conference, Fairbanks, AK

Aug. 2003 K. Hidlebrandt

Sept. 2003 0. Harding

ACCESS NUMBER: TO-15180

0. Harding

B. Kelly

B. Kelly

0. Harding

0. Harding

L. Quakenbush

B. Kelly

B. Kelly

B. Kelly

B. Kelly

B. Kelly

B. Kelly

0. Harding

B. Kelly

ft Kelly

J. Conway

Feb. 1999

Feb. 1999

Mar. 2000

Jul. 2000

Feb. 2001

Feb. 2001

Feb. 2001
SEARCH Open Science Meeting, Seattle,

WA

34th International Arctic Workshop, Boulder.

CO

IEEE Internat!. Geosci. & Remote Sensing

Symposium, Anchorage, AK

ACCESS NUMBER: TO-15180

Oct. 2003 B. Kelly

Mar. 2004 J. Conway

Sept. 2004 S. Nghiem
4

148°41'W

ACCESS NUMBER: TO-15180

The study was conducted on the shorefast sea ice of the Beaufort Sea Bay, Reindeer isiand, between Prudhoc and the man-made Northsrar Island.

70°29'N