Steller Sea Lion Population Status 2009

Alaska Ecosystem ProgramNOAA Fisheries

National Marine Mammal LaboratorySeattle, WA

Lowell Fritz, Kathryn Sweeney, Sara Finneseth, Carolyn Gudmundson and Tom Gelatt NMMLMorgan Lynn, Mark Lowry and Wayne Perryman SWFSC NMFSBrad Fritzler, Doug MacIntyre and ‘Kevin’ Rooteveel NOAA Aircraft Operations CenterVladimir Burkanov Natural Resources ConsultantsPeter Olesiuk Fisheries and Oceans CanadaDon LeRoi Aircraft Imaging Solutions

Outline• Results of 2009 AK Aerial Survey

– Pup Production– Non-Pup Movement in SE Alaska,

Prince William Sound, Kenai and Kodiak• Update Status of western DPS

– Alaska• Update Status of eastern DPS• Vital Rates

– Inferences from survey data– Preliminary mark-resight (branding)

estimates• New Food Habits Information

Alaska Steller Sea Lion Aerial Project 2009

• SSL Pup Production in AK• Seasonal movement in N GOA• 24 June – 15 July• 3 cameras, 85 mm lenses and forward motion compensation– 1 vertical, 2 oblique at 21°– ~ 1,000 ft swath at 750’

• ~ 12,000 miles flown• ~ 15,000 pictures taken• 172/178 sites surveyed

Steller Sea Lion Aerial Survey 24 June-15 July 2009

0

500

1000

1500

2000

2500

3000

3500

4000

4500

Attu (Cape Wrangell)

Agattu/Gillon Point

Agattu/Cape Sabak

Buldir

Kiska/Cape St Stephen

Kiska/Lief Cove

Ayugadak

Amchitka/Column Rock

Ulak/Hasgox Point

Tag

Gramp Rock

Kanaga/Ship Rock

Adak/Lake Point

Kasatochi/North Point

Seguam/Saddleridge

Yunaska

Adugak

Ogchul

Bogoslof

Akutan/Cape Morgan

Akun/Billings Head

Ugamak Complex

Sea Lion Rock (Amak)

South Rocks

Clubbing Rocks

Pinnacle Rock

Jude

Chernabura

Atkins

Lighthouse Rocks

Chirikof

Chowiet

Marmot

Ushagat/SW

Sugarloaf

Outer (Pye)

Chiswell Islands

Wooded (Fish)

Seal Rocks

Graves Rock

White Sisters

Biali Rock

Hazy

Forrester Complex

W ALEU C ALEU E ALEU W GULF C GULF E GULF SE AK

2005 2009

EasternWestern

Alaska Steller Sea Lion Pup Counts

178°W

‐200

‐100

0

100

200

300

400

500

600

700

W Aleu C Aleu E Aleu W Gulf C Gulf E Gulf SE AK

178 W

+203+28%

+1962+36%

2009 – 2005: Difference in SSL Pup Count

‐64‐19%

+355+21%

+169+10%

‐120‐5%

+378+20%

-10

0

10

20

30

40

50

60

70

80

90

100

Western Central Eastern Western Central Eastern . wDPS eDPS

Aleutian Islands Gulf of Alaska . in AK SEAK

2005‐2009 Average Annual Changein Pup Production Per Rookery

Forrester/ North Rock1,223 Pups1,239 Adults and Juveniles

Eastern Stock

Bull

Sub‐Adult Male

Female

Pup

Juvenile

Western StockAdugak ‐ Eastern AleutiansIncreasing277 Pups620 Adults and Juveniles

Bull

Sub‐Adult Male

Female

Pup

Juvenile

Western StockUlak/Hasgox PointCentral AleutiansDecreasing272 Pups515 Adults and Juveniles

Bull

Sub‐Adult Male

Female

Pup

Juvenile

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

W Aleu C Aleu E Aleu W Gulf C Gulf E Gulf AK wDPS SE AK eDPS

3 11 6 4 5 2 0 31 2

Ratio of Pups/Non‐Pups on Rookeries 2009

+6%*

Rate of Change in Pup Production (per year) 2001‐2009

‐7%

‐1%

+5%*

+6%*+1%

+3%

Overall Western DPS in AK: 1.7% ns

0

1,000

2,000

3,000

4,000

5,000

1990 1995 2000 2005 2010

Number of pups

Year

Gulf of Alaska‐ Western DPS

Eastern

Central

Western

3,000

4,000

5,000

6,000

7,000

8,000

1990 1995 2000 2005 2010

Number of Pups

Year

SE AK- Eastern DPS in AK

0

1,000

2,000

3,000

4,000

5,000

1990 1995 2000 2005 2010

Number of Pups

Year

Aleutian Islands- Western DPSEastern

Central

Western

Steller Sea Lion Pup 

Counts

15000

20000

25000

30000

35000

40000

1991 1992 1994 1996 1998 2000 2002 2004 2008

Non-Pup Count

Year

wDPS AK

Kenai-Kiska

Steller Sea Lion Non-Pup Counts Through 2008

7,000

8,000

9,000

10,000

11,000

12,000

1988 1992 1996 2000 2004 2008

Non-pup Count

Year

SE Alaska2% per year growth

1990-2002

1,000

2,000

3,000

4,000

5,000

1988 1992 1996 2000 2004 2008

Non-Pup Count

Year

Eastern Gulf of Alaska

Kayak Island Cape St Elias

Steller Sea Lion Non-Pup Counts Through 2009

7,000

8,000

9,000

10,000

11,000

12,000

13,000

1988 1992 1996 2000 2004 2008

Non-Pup Count

Year

Southeast Alaska+2% / yr

‐2400 in 20081,000

2,000

3,000

4,000

5,000

1988 1992 1996 2000 2004 2008

Non-Pup Count

Year

Eastern Gulf of Alaska+750 in 2008

3,000

4,000

5,000

6,000

7,000

8,000

1988 1992 1996 2000 2004 2008

Non-Pup Count

Year

Central Gulf of Alaska‐180 in 2008

Western Steller Sea Lion Non‐Pup Counts in Alaska

15000

20000

25000

30000

35000

40000

1991 1992 1994 1996 1998 2000 2002 2004 2008

2008 Adjusted for Seasonal Movement

wDPS AK

Kenai-Kiska

Western Steller Sea Lion Non‐Pup Counts in Alaska

Outline• Update Status of eastern DPS• Vital Rates

– Inferences from survey data– Preliminary mark-resight (branding)

estimates

• New Food Habits Information

0

4,000

8,000

12,000

16,000

1980 1985 1990 1995 2000 2005 2010Year

Adults and  Juveniles

SE Alaska

British Columbia

0

1,0002,000

3,0004,0005,000

6,0007,000

8,000

1970 1975 1980 1985 1990 1995 2000 2005 2010Year

Pups

+8%

+5% 

Eastern Stock of Steller Sea Lion (North)

Eastern Stock of Steller Sea Lion (South)

0

1,000

2,000

3,000

4,000

5,000

1989 1993 1997 2001 2005 2009Year

Adults and  Juveniles Oregon all sitesCA rookeries

0

200

400

600

8001,000

1,200

1,4001,600

1989 1993 1997 2001 2005 2009Year

Pups +3%

+5%

Outline• Vital Rates

– Inferences from survey data– Preliminary mark-resight (branding)

estimates

• New Food Habits Information

Non-Pup Trends on Rookeries and Haulouts

0

1,000

2,000

3,000

4,000

5,000

6,000

7,000

1990 1992 1994 1996 1998 2000 2002 2004 2006 2008

Central Aleutian Islands

0

1,000

2,000

3,000

4,000

5,000

1990 1992 1994 1996 1998 2000 2002 2004 2006 2008

Eastern Aleutian Islands

0

1,000

2,000

3,000

4,000

5,000

1990 1992 1994 1996 1998 2000 2002 2004 2006 2008

Western Gulf of Alaska

0

1,000

2,000

3,000

4,000

5,000

6,000

1990 1992 1994 1996 1998 2000 2002 2004 2006 2008

Central Gulf of Alaska

0

500

1,000

1,500

2,000

2,500

3,000

3,500

1990 1992 1994 1996 1998 2000 2002 2004 2006 2008

Rookeries

Haulouts

Eastern Gulf of AlaskaIn Core of Range (Kenai-Kiska):Increasing or Stable on RookeriesDeclining or Stable on Haulouts

Decline in Recent Recruitment ?Decline in Birth Rates ?

In Eastern GOA:Increasing on RookeriesIncreasing on Haulouts

Trends in Pups and Non-Pups on Rookeries Only in Increasing Sub-Areas 2000-2009

0%

1%

2%

3%

4%

5%

6%

7%

E Aleu W Gulf E Gulf SE AK

Annual Rate of Increase

Non‐Pups Pups

At ROOKERIES in 2 increasing wDPS sub‐areas

Pups increasing slower than non‐pups

At ROOKERIES in E Gulf (wDPS) and SE AK (eDPS)

Pups increasing faster than non‐pups

• Started with mid-1970s life table

• Fit changes in Pup and Non-pup Counts and Size Distribution on Haulouts by changing Vital Rates

• Since late 1980s

• Increasing survivorship

• Decreasing birth rate

Central Gulf of Alaska Survivorship and Natality

0.30.40.5

0.60.70.80.9

1.01.1

1976-1982 1983-1987 1988-1991 1992-1996 1997-2004

Juvenile Survivorship

0.80

0.85

0.90

0.95

1.00

1.05

1.10

1976-1982 1983-1987 1988-1991 1992-1996 1997-2004

Adult Survivorship

0.5

0.6

0.7

0.8

0.9

1.0

1.1

1976-1982 1983-1987 1988-1991 1992-1996 1997-2004

Birth RateHolmes, Fritz, York, and Sweeney.

Dec 2007 Ecological Applications

0.000.050.100.150.200.250.300.350.400.450.500.550.600.65

1970s 1970s Late 80s 1984‐88 1998‐04 2000s 2000s 2000s 2000s 2000s 2000s Late 90s

Females Females Females & Males

Females Females Females Females Females Males Females & Males

Females & Males

Females

Marmot CGOA Marmot CGOA CGOA  Marmot Ugamak PWS PWS PWS PWS Forrester

Life Table Model Branding Model Model Branding Branding Branding Branding Branding LHX Branding

‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐Western DPS‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐ EasternDPS

Cumulative Survival to Age 3

Females FemalesFemalesFemalesFemalesFemalesFemalesFemales

Period

Sex

Rookeryor Region

Method

Outline• New Food Habits Information

A Cooperative Pollock Acoustic Biomass Survey for Management of Fisheries Interactions with Steller Sea Lions in the Aleutian Islands

Elizabeth Logerwell and Steve Barbeaux – NOAA Fisheries/Alaska Fisheries Science CenterLowell Fritz – NOAA Fisheries/National Marine Mammal Laboratory

To investigate the feasibility of cooperative pre‐fishery biomass surveys as a means to 

manage fisheries at local scales important to Steller sea lions

-0.3

-0.2

-0.1

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

-0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4 0.5 0.6

SE ofSalt

Atka/North Cape

Adak/Head Rock+

Kagalaska

Kanaga/Ship Rock

Amlia/Sviech. Harbor

Adak/CroneIsland

Anagaksik

KasatochiAmlia/East Cape

Atka mackerel

Pollock

Both

Steller Sea Lion Food Habits• 2‐12 April 2008• Atka mackerel, Rockfish spp. Pacific cod and pollock most common prey• Principal component analysis of top 7 prey revealed 3 groups of sites

• High pollock/Low mackerel, all located near spawning aggregations• High pollock/High mackerel (Kanaga‐Ship Rock)• Low pollock/High mackerel, none near spawning aggregations

Pollock Acoustic Surveys• ~ 29,000 mt of pollock• 3 spawning aggregations 

Steller Sea Lion Aerial Survey• 24‐25 March 2008• Total count = 3,236 sea lions• 90% were adult females or juveniles 

Walleye pollock size ranged from 41.6cm to 73.7cm based on regressions of bones recovered from scat samples (n= 14 bones from 6 scat samples).

Percent frequency of occurrence of prey species found in Steller sea lion scat samples collected at Dalnoi Point, St. George Island, June 2009 (n = 27 scats).

Percen

t Frequ

ency 

Summary• Update Status of western DPS

– Increased from 2000‐2004– Stable from 2004‐2008/9– Considerable regional variability in recent trends and 

responses in the population• Continued declines west of 178°W in the Aleutians• Stable 170‐178°W in the Aleutians• Increasing eastern Aleutians and western Gulf• Stable central Gulf• Increasing eastern Gulf

– Regional differences in vital rate responses• Eastern Aleutians through Eastern Gulf

– Improvements in survival from 80s through 2000s– Evidence for reductions in natality,

• Western and Central Aleutians– Unknown, but likely continued decline in all vital 

rates

• Update Status of eastern DPS– Continued improvement central CA through SE AK

NMML SSL Research in 2010• Population Assessment

– Aerial Survey in Alaska: June and early July– Adults and Juveniles (Non‐Pups)– Both ‘early’ and ‘late’ surveys in northern Gulf

• Survival and Reproduction– Sightings of marked animals: Summer

• Boat‐based eastern Aleutian Islands through PWS• Cape St. Elias: early June• Field camps on Marmot and Ugamak Islands

– Permanent marking of pups in central Gulf: July• 100 on Marmot and 100 on Sugarloaf

• Adult female capture (possible)– Fall 2010 or Late Winter 2011

Questions?

Kayak Island9‐13 June

• 857 total adult and juvenile SSLs– 1400  aerial on 9 June 2008

• 38 branded animals– 31 western stock brands

• 17  1‐year‐olds from Marmot, Sugarloaf & Chiswell• 3  2‐3 year olds, 11 4‐8 years old

– 7 eastern stock brands 3‐6 years old– ~ ¼ of SSLs from the east

• Ratios of those seen to those alive

Eastern Kamchatka Non‐Pups‐81% decline since 1983

Western Bering Sea Non‐Pups 

98% decline since 1982

0

2,000

4,000

6,000

1982

1985

1988

1991

1994

1997

2000

2003

2006

2009

Individu

las

SSL (non pups) Abundance in Western Bering Sea, 1982‐2008

0

500

1000

1500

2000

2500

1983

1986

1989

1992

1995

1998

2001

2004

2007

Individu

las

Commander Island SSLs • Non-Pups increase 1930-1950s followed by decline through 80s• Rookery reestablished late 70s• Pups increase through 1990s• 2000-2008 stabilized at low level

• 700-800 non-pups• 220-250 pups

Medny I. rookery 2009Change from 2008

• pup born 175 -21% • non-pup, max 391 -27%• females, max 244 -17%• Bulls total, max 80 -10%• Bulls ter., max 44 -20%

-No decline in number “M” branded animals resighted in 2009-Clear negative trend in female birth rates (preliminary estimates, analysis in progress)-No significant changes in survival rates (preliminary estimates, analysis in progress)

0

50

100

150

200

250

300

0

1,000

2,000

3,000

4,000

5,000

6,000

1930

1938

1946

1954

1962

1970

1978

1986

1994

2002

2010

Pups

Non

‐pup

 Individu

las

SSL Abundance in the Commander Islands 1930‐2009

Kuril Island Pups:

2000 – 2007 increase 6% / year

2009 – No significant changes (analysis in progress)

0

500

1000

1500

2000

2500

3000

3500

4000

1960

1965

1970

1975

1980

1985

1990

1995

2000

2005

Pup Co

unt

SSL pup production in Kuril  Islands 1960s‐2008

Sakhalin Island SSLs • VERY low number till early 80s.• One rookery established in early 80s on Tuleny (Robben) I.• Pups number is growing rapidly through 1990s and 2000s. Mean trend in pup production 1983-2009 is 21%• High pup trend due to immigration SSL from Iony I. in northern Sea of Okhotsk (brand resight data)• Tuleny I Rookery in 2009:

• ~ 1200 non-pups• ~ 500-700 pups2009 survey results:

• three more SUMMER SSL haulout sites re-established in southern Sakhalin (they were only winter sites in the past)

• 2,000 non-pups and 11 pups were counted on the three haulout sites• branded SSL were from northern Sea of Okhotsk and Kuril Islands

0

100

200

300

400

500

600

700

800

020040060080010001200140016001800

1955

1960

1965

1970

1975

1980

1985

1990

1995

2000

2005

2010

Pups

Non

‐pup

s

SSL Abundance in the Sakhalin 1955‐2009

Trends on HauloutsNo increase on haulouts except

in the Eastern GulfMovement from SE AK

0

1,000

2,000

3,000

4,000

5,000

6,000

1990 1992 1994 1996 1998 2000 2002 2004 2006 2008

Central Gulf of Alaska

0

1,000

2,000

3,000

4,000

5,000

1990 1992 1994 1996 1998 2000 2002 2004 2006 2008

Western Gulf of Alaska

0

1,000

2,000

3,000

4,000

5,000

1990 1992 1994 1996 1998 2000 2002 2004 2006 2008

Eastern Aleutian Islands

0

1,000

2,000

3,000

4,000

5,000

6,000

7,000

1990 1992 1994 1996 1998 2000 2002 2004 2006 2008

Central Aleutian Islands

0

500

1,000

1,500

2,000

2,500

3,000

3,500

1990 1992 1994 1996 1998 2000 2002 2004 2006 2008

Western Aleutian Islands

0

500

1,000

1,500

2,000

2,500

3,000

3,500

1990 1992 1994 1996 1998 2000 2002 2004 2006 2008

Eastern Gulf of Alaska

SSL survey areas in Russian watersV. Burkanov

(Work funded by NMML and ASLC)

‐Six survey areas are established in Russian waters for surveys. 

‘Western’ Stock

‘Asian’Stock

WBS CI EK Kurils Japan Sakhalin NPSO

Total SSL Abundance in Russia:

Burkanov, V. et al. Update on Steller sea lion surveys in Russia, 2006‐2008.  Poster at AK Marine Science Symposium.  Jan. 22, 2009

-600

-400

-200

0

200

400

600

800

1000

Cha

nge

in N

P C

ount

(200

8A-2

000)

C ALEU E ALEUWALEU

W GULF C GULF EGULF

+39%+28% +93%- 3%- 11%- 45%

AK Western Stock: +14%Kenai-Attu: +6%

Kenai-Kiska: +10%

Compare 2008 & 2000

Western SSL Non-PupCounts in Alaska