Ringed Seals (Phoca hispida) as Indicators of Ecosystem Changes Magaly Chambellant and Steve H. Ferguson ArcticNet 7 th Annual Scientific Meeting
Ringed seal biology small and long lived phocid northern circumpolar distribution ice-dependent www.beaufortseals.com J. Moran
P. Nicklen Poster by D. Yurkowski #155 pupping from Mansfield 1967 weaning/mating www.fugly.com W. Turnbull J. Stewart winter spring moult territoriality break-up autumn summer J. B. Dunn freeze-up intense feeding http://nas.er.usgs.gov www.wikipedia.org P. Nicklen C. Nozères
Ringed seal biology sensitive to environmental changes light/heavy ice and early/late break-up rain in spring insufficient snow depth ringed seals could face critical challenges with current climatic trends, especially at southern limit of species range
Study site Arviat in western Hudson Bay first long-time series data for ringed seals (1991-2006) Arviat Hudson Bay
Objectives asses role of environment and understand mechanisms involved in ringed seal population dynamics in the western Hudson Bay ecosystem provide management advice baard naess
Life-history 1990s 2000s Percent pups in fall harvest 5.5 17.8 Pregnancy rate (%) 56 84 Median age (yr) 9 4 Age at maturity/first parturition (yr) 5.4 / 7.3 3.8 / 5.5 Growth/length (cm) 114 123 decline increase
Summary 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 Year
Summary Ringed seal density (seals/km 2 ice) 2.5 2.0 1.5 1.0 0.5 0.0 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 Year
Ringed seal density (seals/km 2 ice) 2.5 2.0 1.5 1.0 0.5 0.0 Introduction El Niño/NAO/Pinatubo heavy ice Summary 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 Year
http://news.bbc.co.uk www.coolpicturegallery.net Predation pressure www.saskschool.ca heavy ice - late break-up hunting season lemmings seal pups Introduction P. Nicklen www.itsnature.org early 1990s body condition natality lemmings www.images.net www.selfhelpdaily.com
Diet composition Fish=95% Invertebrates=5% Arctic cod Capelin Other Invertebrates Sand lances IG=75% Other Fish Rainbow smelt Amphipods Other cods Sculpins 0 1 2 3 4 5 6 7 8 9 10 Global importance index (%)
Temporal variation Diet 100 90 * Sand lances Sculpins Arctic cod Global importance index (IG) 80 70 60 50 40 30 20 10 low sand lances benthic prey Other cods Rainbow smelt Capelin Other fish Amphipods Other invertebrates 0 91 92 93 94 95 96 97 98 99 00 01 02 03 04 05 06 Year
Temporal variation 100 Global importance index (IG) 90 80 70 60 50 40 30 20 Sand lances Sculpins 10 0 91 92 93 94 95 96 97 98 99 00 01 02 03 04 05 06 Year
Temporal variation 100 90 * Sand lances Sculpins Arctic cod Global importance index (IG) 80 70 60 50 40 30 20 more diverse Other cods Rainbow smelt Capelin Other fish Amphipods Other invertebrates 10 0 91 92 93 94 95 96 97 98 99 00 01 02 03 04 05 06 Year
Specialization Total energy consumed (MJ) 100 80 60 40 20 0 r 2 =0.86 30 40 50 60 70 80 90 100 110 Sand lances IG
Environment 140 120 r 2 =0.52 p=0.028 Sand lances IG 100 80 60 40 20 140 150 160 170 180 190 200 210 Break-up date (Julian day)
population dynamics follow decadal cycle heavy ice in early 1990s low sand lances energy loss nutritional stress low reproductive output low pup survival decrease abundance www.igpp.ucsd.edu I. Stirling bottom-up and top-down processes D. Getty Ringed seal density (seals/km 2 ice) 2.5 2.0 1.5 1.0 0.5 0.0 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 Year
good indicator species of ecosystem changes long-term monitoring needed J. Moran
Acknowledgments Ian Stirling and Nick Lunn Sebastián Luque Becky Sjare and Dave McKinnon Lois Harwood Tara Bortoluzzi, J. Blair Dunn, Ashley Gaden, Megan Jack, Trish Kelley, Lisa Loseto, Tracy Loewen, Cory Matthews, Brent Young Frank Nutarasungnik, hunters and HTO from Arviat, NU Nunavut Wildlife Management Board Canadian Wildlife Service - Environment Canada Nunavut Implementation Fund