Effects of a Retreating Ice Effects of a Retreating Ice Ed i th B i SEd i th B i SEdge in the Bering Sea on Edge in the Bering Sea on

Fisheries ActivitiesFisheries ActivitiesFisheries ActivitiesFisheries ActivitiesP.R. MundyP.R. Mundy

Alaska Fisheries Science Center, Auke Bay LaboratoriesAlaska Fisheries Science Center, Auke Bay Laboratories

S i th I t f IS i th I t f I Di i i hi A ti Di i i hi A ti

Ted Stevens Marine Research InstituteTed Stevens Marine Research InstituteJuneau, Alaska USAJuneau, Alaska USA

Symposium on the Impact of an IceSymposium on the Impact of an Ice--Diminishing Arctic Diminishing Arctic on Naval and Maritime Operationson Naval and Maritime Operations

U.S. Navy Memorial and Naval Heritage Center in Washington, D.C. U.S. Navy Memorial and Naval Heritage Center in Washington, D.C. July 10 July 10 –– 12, 200712, 2007

Fishing Activities

• Large scale industrial (Bering)• Resource dependent communities (BeringResource dependent communities (Bering

Sea north)Coastal communities commercial (CDQ)– Coastal communities commercial (CDQ)

– Subsistence – fish, birds and mammals

Outline of Effects on FisheriesOutline of Effects on Fisheries Activities

Sea Ice Physics Biology& CO2 Chemistry2 y

Abundance & distribution birds, fish and mammals

Abundance & distribution of harvesters

Alaskan Fisheries Scientists Cope with Climate Change, Beaufort Sea Summer 2006

Ti dTime and space scales for birds fishfor birds, fish and mammals are small

Photo credit: Scott Johnson and John Thedinga, NMFS/AFSC/ABL/TSMRI

State of the Climate in 2005 Bull. Am. Meteorol. Soc.

Summary of Fisheries EffectsSummary of Fisheries EffectsSummary of Fisheries EffectsSummary of Fisheries Effects

Increased Increased subarctic subarctic 165Wsubarctic subarctic habitathabitatIncreased Increased

165W

Increased Increased pollock, cod pollock, cod and and 60 N

200m

a da darrowtooth arrowtooth flounder flounder abundanceabundanceDecreased Decreased

b b crab crab abundanceabundance

ICE

58

57L ti f i t tMaximum ice extent

Location of ice extent

Loss of sea ice

Percent ice coverageg

P.J. Stabeno, PMEL

Sea Ice Physics BiologyIce Timing Wind SunIce Timing, Wind, Sun, Nutrients & Temperature Productivity

More zooplankton

Less zooplankton

Oscillatory Control HypothesisH t GL J P St b G W lt E Si l i R D B d J M N N AHunt, GL Jr., P. Stabeno, G. Walters, E. Sinclair, R.D. Brodeur, J.M. Napp, N.A. Bond. 2002. Climate change and control of the southeastern Bering Sea pelagic ecosystem. Deep-Sea Res. 49: 5821-5853.

Early bloom favors benthic production

Bottom-up si

sp

control

Hyp

othe

s BENTHIC-PELAGIC SPLIT

Late bloom favors pelagic production

ontr

ol H

ator

y C

oO

scill

a

Top down control

Hunt, GL Jr., P. Stabeno, G. Walters, E. Sinclair, R.D. Brodeur, J.M. Napp, N.A. Bond. 2002. Climate change and control of the southeastern Bering Sea pelagic ecosystem. Deep-Sea Res. 49: 5821-5853.

Physics, Uncertainty #1: Extent of renewal of nutrients during the summer

•Reduced

of nutrients during the summer

winds•Summer and fall windsfall winds renew photic zone nutrients depleted by spring bloom

P.J. Stabeno, PMEL from Hunt et al. 2002

Composition variable

Biology: Summer Secondary Production

Zooplankton biomass declining?va ab eProduction

2000

Napp et al., Regulation of zooplankton standing stock and production in the southeast Bering Sea: Top-down v. bottom-up control and recent climate-related declines in a subarctic ecosystem. Prog. Oceanogr., submitted.Photos: M. Flint & T. Whitledge 2001

Reduced Summer Wind =Reduced juvenile fish survivalj

Juvenile fish and other small

Pollock

Juvenile fish and other small pelagic organisms need to gain sufficient energy during

t i th i tsummer to survive the winter

SS

B)

tmen

tlo

g (R

/

Rec

ruit

Mueter, F.J., C. Ladd, M.C. Palmer, B.L. Norcross. 2006. Bottom-up and top-down controls of walleye pollock (Theragra chalcogramma) on the Eastern Bering Sea shelf. Prog. Oceanogr. 68: 152-183.

Biology, Uncertainty #2 Arrowtooth flounder biomass (age-2+)(thousands mt)

1250

750

1000

1250Less ice means more top down control of ecosystem:

0

250

500y

Arrowtooth flounder abundance is increasing in the Bering Sea

Walleye pollock biomass (age-3+)

01977 1982 1987 1992 1997 2002

the Bering Sea

(millions mt)

10

15

5

10

Bailey, K.M., Brodeur, R.D., Hollowed, A.B. 1996. Cohort survival patterns of walleye

01964 1974 1984 1994 2004

survival patterns of walleye pollock, Theragra chalcogramma, in Shelikof Strait, Alaska: A critical factor analysis. Fish. Oceanogr. 5:1.

Pollock ( ) respond to changes in ocean temperature as do fur seals ( )

Biology: Which species will

Bottom tem

-1.6 - -1.5-1.4 - -1-0.9

Alaska

1999

ocean temperature, as do fur seals ( )species will survive, which will disappear? -1.6C

Location matters:

mperature (degrees

9 - -0.5-0.4 - 00.1 - 0.50.6 - 11.1 - 1

50 0 mmatters: surviving loss of sea ice

s C)

- 1.51.6 - 22.1 - 2.5

2.6 - 33.1 - 3 5

0 90 18045 Km

Bering Sea Basin ~ 3000 meters

0 meters

depends on mobility

Alaska

2000

.53.6 - 44.1 - 4.5

4.6 - 55.1 - 5.55

Bering Sea Basin ~ 3000 meters

50 0 meters

5.6 - 66.1 - 6.56.6 - 77.1 - 7.5

7.6 8C0 90 18045 Km

.6 - 8

J. Sterling, AFSC

8C