1

The Effects of Changes in Sea Ice Coverage on

Bearded Seal Populations Sizes and Reproduction in

Hudson Bay Emily Wang

COSMOS 2013

2

Introduction: Global Climate Change

• Causes (Karl & Trenberth 2003)o Human energy useo Urbanizationo Land use changes

• Sea ice losses o Last summer were the highest in recorded

history (Gagnon & Gough 2005)

• Affects marine animalso e.g. polar bears need ice to breed and

Hunt (Smith 1980)

globalwarmingfacts.net

• Live near Greenland, the Arctic, Alaska, and Canada (Hudson Bay)

• Need ice to breed (platform)

• Less ice = Swim longer distances -> Habitat Fragmentation

• Breeding season: late April or early May

Introduction: Bearded Seals (Erignathus barbatus)

What Are the Effects of Changes in Sea Ice Coverage on Bearded Seal

Populations Sizes and Reproduction in the Hudson Bay?

Question

Robert Rosing–National Geographic

A decrease in ice coverage in the Hudson Bay will be correlated with:

A) A decline in the population

B) A decline in the birth rate of pups

Hypothesis

Robert Rosing–National Geographic

Method: Sea Ice Coverage• Use Special Sensor

Microwave/Imagers satellites F8, F11, and F13 to measure microwave radiation (Johannessen et al 1999)

• Use ArcGIS to analyze data (Johnston et al 2001)

• Measure volume of sea ice coverage every month

• Find yearly average each year from 2015 to 2025

• Observe duration of the ice-free season each year from 2015 to 2025

www.noaanews.noaa.gov

Method: Population

• Use aerial surveys (Myers & Bowen 1989)

• Count population in 10% of the area each month by using evenly spaced vertical lines 65 miles apart

• Multiply by 10 to estimate total population

• Find yearly average for 10 years from 2015-2025 65 miles

withfriendship.com

Method: Birth Rate of Pups• Use of aerial surveys• Count pup population in 10% of

the area by using evenly spaced vertical lines 65 miles apart

• Each mating season (April-May) for 10 years (McLaren 2011)

www.aerialsurvey.de

withfriendship.com

Predicted Results

2014 2016 2018 2020 2022 2024 20260

100000

200000

300000

400000

500000

600000

700000

800000

Changes of Sea-ice Coverage in Hudson Bay over 10 Years

Ice Content Area (km2)Linear (Ice Content Area (km2))

Years

Ice

Cont

ent

Area

(km

2)

Predicted Results (Continued)

2014 2016 2018 2020 2022 2024 2026170

180

190

200

210

220

230

Length of Ice-free Season in Hudson Bay over 10 Years

Length of Ice-free Season (days)

Linear (Length of Ice-free Season (days))

Years

Leng

th o

f Ic

e-fr

ee S

easo

n (d

ays)

Predicted Results (Continued)

0 100000 200000 300000 400000 500000 600000 700000 8000000

50000

100000

150000

200000

250000

300000Population and Birth Rate of Pups In Coalition to Sea-

ice Coverage

Bearded Seal Overall PopulationLinear (Bearded Seal Overall Population)Linear (Bearded Seal Overall Population)

Ice Content Area (km2)

Popu

latio

n #

Discussion

• Climate change increases → sea ice coverage decreaseso Decreased by 1400 km2/year from 1978-1996 (Gagnon

& Gough 2005)o Now decreasing by

more and more each year

o If this continues, only 750,000km2 in 2015 and 50,000km2 by 2025

o Decrease to only 1/15 of original coverage in just 10 years

www.polarprince.com

Discussion (Continued)

• Climate change increases → duration of the ice-free season increaseso In the past ice-free

season has been from mid-August to late October (Gagnon & Gough 2005)

o Around 75 dayso If this continues, it will

rise to 187 days in 2015 to 221 days by 2025

walrusmagazine.com

http://images.nationalgeographic.com

Discussion (Continued)

• Dropped from 250,000 in 2015 to 125,000 by 2025Decreasing Sea-

ice Coverage

Increasing Duration of Ice-

free Season

www.polarprince.comlatimesblogs.latimes.com

• Dropped from 250,000 in 2015 to 125,000 by 2025

The Number of Bearded Seals

latimesblogs.latimes.com

Discussion (Continued)

• Went from 62,000 in 2015 to 41,000 in 2025

Less Sea Ice Less Breeding

Smaller Number of Pups Born Each Year

Conclusion• Other species (e.g. polar bears) are also greatly

impacted by sea ice loss like bearded seals (Smith 1980)o Many rely on ice for breeding, feeding, molting,

etc.• Decline of the bearded seal population also

affects other animals, which in turn affects even more animalso e.g. less bearded seals causes polar bears to

venture towards other prey → less ringed seals and harp seals → ultimately less polar bears (Thiemann et al 2008), (Wolkers et al 2004)

• Help predict future changes in seal populations

BibliographyGagnon, Alexandre S., and William A. Gough. "Trends in the Dates of Ice Freeze-up and Breakup over

Hudson Bay, Canada." Arctic 58.4 (2005): 370-82. Print.Johannessen, Ola M., Elena V. Shalina, and Martin W. Miles. "Satellite Evidence for an Arctic Sea Ice

Cover in Transformation." Science 286.5446 (1999): 1937-939. Web.Johnston, Kevin, Jay M. Ver Hoef, Konstantin Krivoruchko, and Neil Lucas. Using ArcGIS Geostatistical

Analyst. Redlands: ESRI, 2001. Print.Karl, Thomas R., and Kevin E. Trenberth. "Modern Global Climate Change." Science 302.5651 (2003):

1719-723. Web. 30 July 2013.McLaren, I. A. "Some Aspects of Growth and Reproduction of the Bearded Seal, Erignathus Barbatus

(Erxleben)." Calanus 13th ser. (1958): 219-27. Web.Myers, R. A., and W. D. Bowen. "Estimating Bias in Aerial Surveys of Harp Seal Pup Production." The

Journal of Wildlife Management 52.2 (1989): 361-72. Web.Smith, T. G. 1980. Polar bear predation of ringed and bearded seals in the land-fast sea ice habitat.

Can. J. Zool. 58: 2201-2209.Thiemann, Gregory W., Sara J. Iverson, and Ian Stirling. "Polar Bear Diets and Arctic Marine Food

Webs: Insights from Fatty Acid Analysis." Ecological Monographs 78.4 (2008): 591-613. Web.

Wolkers, Hans, Bert V. Bavel, Andrew E. Derocher, Oystein Wiig, Kim M. Kovacs, Christian Lydersen, and Gunilla Lindstrom. "Congener-Specific Accumulation and Food Chain Transfer of Polybrominated Diphenyl Ethers in Two Arctic Food Chains."Environmental Science & Technology 6th ser. 38 (2004): 1667-674. Web.

Acknowledgements

I would like to thank Dr. Shawn Noren, Patrick Robinson, Walter, and Katy Kriscunas for providing me with this wonderful experience and supporting me through my research.

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