Monitoring marine bird distributions across the sub-arctic North Pacific using

platform of opportunity vessels (2002-2005):

Seasonal and Interannual Variability

 

David Hyrenbach, Mike Henry, Chris Rintoul, Ken Morgan William Sydeman

khyrenba@u.washington.edu

Motivation: Ecosystem Understanding

Approach: CPR-MBM Surveys

June 2002

Oct. 2002

• Surveys started in June 2002

• Three seasonal cruises (April, June, October) each year

• East - West track: 7500 km, British Columbia to Hokkaido

Distance (m)

0

25

50

75

100

0

25

50

75

100

Observed (Flying)Observed (Sitting)Expected

0-100 100-200 200-400 400-800

Black-legged Kittiwake

1 2 3 4

Survey Bin

0

25

50

75

100

0

25

50

75

100

Pro

porti

on (%

)

Survey Bin

Sooty Shearwater

• Survey platform: Skaubryn Height: 10 / 28 m

Speed: 4.0 - 14.0 knots

• Pilot surveys: June / October 2002

• Standardized strip surveys: 400m transect, one-side of track

Methods: Seabird Surveys

Results: Community Structure

• Phyto / Zoo plankton and seabird community structure in summer (June 2002)

(Batten et al., In Press)

(15 – 25 km)

BC shelf / slope Eastern GoA Central GoA Western GoA E. Aleutian shelf W. Aleutian shelf Aleutian Basin SW. Bering Sea W. Open Pacific Coastal N. Japan

(18.5 km)

Results: Meso Marine Ecosystems

-8000

-6000

-4000

-2000

0

Dep

th (m

)

140 150 160 170 180 190 200 210 220 230 240

Longitude (E)BCSS

WGA CGA EGA

EAS

CNJapan WOP WBS AB WAS (Batten et al., In Press)

Applications: Three Case Studies

British Columbia Shelf /Slope

Eastern Aleutian Shelf

Gulf of Alaska

• 11 Cruises, Effort: 846 + 98 km

Spring (2003, 2004, 2005)

Summer (2002, 2003, 2004, 2005)

Fall (2002, 2003, 2004, 2005)

With 2 - 4 birds m -2, this flock contained 4 - 9 million shearwaters ~ 13 – 30 % of the world population

Example 1: Identify “Hotspots”

Photo: Mike Britain

Trans-Pacific Shearwater Distributions

• Seasonal migration

• Interannual variability: High in fall 2002; Low in fall 2003

• Spatial aggregation

June 2002 – April 2004

2002 2003

2004 2005

200 km

Replicate Summer Surveys (2002-2005)

Unimak Pass, shelf waters (depth < 200m)

Is Unimak Pass a Shearwater Hotspot?

Year Counts Effort (km2) Birds Density (# km-2)

2002 58 51.64 25,909 501.68

2003 25 23.71 581,272 24,510.73

2004 113 74.22 201,858 2,719.76

2005 80 47.68 564,137 11,831.24

Example 2: Community Structure

• Breed off Chile

• Dispersal from colonies in March - May

• Range into North Pacific from April - October

(Harrison, 1984)

Pink-footed Shearwater

(Puffinus creatopus)

Seasonal and Interannual Patterns

Season

Pro

po

rtio

n (

%)

0

20

40

60

80

100

EffortSightingsIndividuals

Spring Summer Fall

• Northward range extension in summer (June) and fall

(Oct.)

(p < 0.001)(p < 0.001)

Pink-footed Shearwater (Summer)

Year

2002 2003 2004 2005

Rel

ativ

e A

bund

ance

(bird

s / 1

00 k

m 2 )

0.1

1

10

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

2.5

2002 2003 2004 2005

Ano

mal

y of

Abu

ndan

ce

(bird

s / 1

00 k

m 2 )

Rel

ativ

e Im

port

ance

(%

)

0

20

40

60

80

100

Pink-footed ShearwaterSooty ShearwaterBlack-legged Kittiwake

2002 2003 2004 2005

Year

Changing Community Structure

• Incursions of subtropical and sub-Arctic species

128.5 124.550.5

47.5

2000m 1000m 200m

Vancouver Island

• Restricted to the shelf and shelf-break (depth < 1000 m)

Example 3: Range Shifts

• Breed in French Polynesia

• Off California as early as April(Harrison, 1984)

Murphy’s Petrel (Pterodroma ultima)

Gulf of Alaska Surveys

###########################################################

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

##

#

##

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

# #

#

#

# #

#

#

# #

#

#

# #

#

#

# #

#

#

# #

#

#

# #

#

#

# #

#

#

# #

#

#

# #

#

#

# #

#

#

# #

#

#

# #

#

#

# #

#

#

# #

#

#

# #

#

#

# #

#

#

# #

#

#

# #

#

#

# #

#

#

# #

#

#

# #

#

#

# #

#

#

# #

#

#

# #

#

#

# #

#

#

# #

#

#

# #

#

#

# #

#

#

# #

#

#

# #

#

#

# #

#

#

# #

#

#

# #

#

#

# #

#

#

# #

#

#

# #

#

#

# #

#

#

# #

#

#

# #

#

#

# #

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

#

##

#

#

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

####

####

####

####

####

####

####

####

####

####

####

####

####

####

####

####

####

####

####

####

###

###

###

###

###

###

###

###

###

###

###

###

###

###

###

###

###

###

###

###

###

###

###

#

ââââ

â

################################################################################################

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ###

# ###

# # #

#

# # #

#

# # #

#

# # #

#

# # #

#

# # #

#

# # #

#

# # #

#

# # #

#

# # #

#

# # #

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

##

#

#

###

#

##

#

#

##

#

#

##

#

#

##

#

#

###

#

###

#

###

#

###

#

###

#

###

#

###

#

###

#

###

#

##

#

#

##

#

#

###

#

###

#

###

#

###

#

##

#

#

##

#

#

##

#

#

##

#

#

###

#

###

#

###

#

###

#

###

#

###

#

###

#

###

#

###

#

###

#

###

#

###

#

###

#

###

#

###

#

###

#

###

#

###

#

###

#

###

#

###

#

###

#

###

#

###

#

###

#

###

#

###

#

###

#

###

#

###

###

###

#

###

#

###

#

###

###

#

###

#

###

#

###

#

## #

#

###

#

###

#

## #

#

## #

#

## #

#

## #

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

# ##

#

###

#

###

#

###

#

###

#

###

#

###

#

###

#

###

#

###

#

###

#

###

#

###

#

###

#

###

#

###

#

###

#

###

#

###

#

###

#

###

#

###

#

###

#

###

#

###

#

###

#

###

#

###

#

###

#

###

#

###

#

###

#

###

#

###

#

###

#

###

#

###

#

###

#

###

#

###

#

###

#

###

#

###

#

###

#

## #

#

## #

#

## #

#

## #

#

## #

#

## #

#

## #

#

## #

#

## #

#

## #

#

## #

#

## #

#

## #

#

## #

#

## #

#

## #

#

## #

#

## #

#

##

#

## #

#

## #

#

## # ## #

#

## #

#

## #

#

## #

#

## #

#

## #

#

## #

#

## #

#

## #

#

## #

#

## #

#

## #

#

## #

#

## #

#

## #

#

## ##

## ##

## ##

## # ## ##

## ##

## ##

## ##

## ##

## ##

## ##

## ##

## ##

## ##

## ##

## ##

## ##

## ##

## ##

## ##

## ##

## ##

## ##

## ##

## ##

## ##

## ##

## ##

## ##

## ##

## ##

## ##

## ##

## ##

## ##

## ##

## ##

## ##

## ##

## ##

# ## ## ## ## ## ## ## ## #### #### #### #### #### #### #### #### ### #### #### #### #### #### #### ####

â âââââââââââââââ

â âââââ

################################################

###########################################################

#####

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

##

##

##

##

##

##

##

###############################################################

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

##

# ## ## ## ## ## ## ## ## ## ## ## ## ## ## ## ## ## ##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

##

#

# ##

# ##

# ##

# ##

# ##

# ##

# ##

# ##

# ##

# ##

# ##

# ##

# ##

# ##

# ##

# ##

# ##

# ##

# ##

# ##

# ##

# ##

# ##

# ##

# ##

# ##

# ##

# ##

# ##

# ##

# ##

# ##

# ##

# ##

# ##

# ##

# ##

# ##

# ##

# ##

# ##

# ##

# ##

# ##

# ##

# ############################### ### ### ### ### ### ### ### ### ### ### ### ### ### ### ### ### ### ### ### ### ### ### ### ### ### ### ### ### ### ### ### ### ### ### ### ### ### ### ### ### ### ### #######

âApril:

3 cruises, 4 birds

June:

4 cruises, 27 birds

October:

4 cruises, 7 birds

Seasonal and Interannual Patterns

Season

Pro

po

rtio

n (

%)

0

20

40

60

80

100

EffortSightingsIndividuals

Spring Summer Fall

• Present in the Gulf of Alaska in April, June and October

(p < 0.001)

Murphy's Petrel (Summer)

Year

2002 2003 2004 2005

Rel

ativ

e A

bund

ance

(bird

s /

100

km 2 )

0.1

1

10

-3

-2

-1

0

1

2

3

4

5

2002 2003 2004 2005

Ano

mal

y of

Abu

ndan

ce

(bird

s /

100

km 2 )

(p < 0.001)

Changing Community Structure

Year

2002 2003 2004 2005

Rel

ativ

e Im

port

ance

(%

)

0

20

40

60

80

100

Leach's Storm-petrelSooty ShearwaterFork-tailed Storm PetrelTufted PuffinNorthern FulmarHorned PuffinBlack-legged KittiwakeParakeet Auklet

2002 2003 2004 2005

Bird

Den

sity

(#

km -2

)

0

5

10

15

20

25

Cluster Tree

0 5 10 15Distances

Y2002

Y2003

Y2004

Y2005

Cluster Tree

• Year-to-year changes in summer seabird abundance and species composition

Eastern Sub-

Arctic

WesternSub-Arctic

California CurrentNorth

Pink-footedShearwater

+ + 27,000

Murphy’s Petrel

? - 60

Short-tailedShearwater

220,000 430,000 14,000

SootyShearwater

1.6 million 3.1million 125,000

(Hunt et al. 1990, PICES Sci. Rept. 14)

Regional Implications

• Consumption of marine resources, transfer of energy

• Quantify large-scale distribution and abundance

• Interpret seasonal and interannual changes

(Hyrenbach & Veit, 2003) (Adams et al., unpublished)

Basin-Wide Implications

Sooty Shearwater

Oceanographic Conditions (2002-2005)

Time (year)

1998 2000 2002 2004 2006-3

-2

-1

0

1

2

3

-3

-2

-1

0

1

2

3

1998 2000 2002 2004 2006-5.0

-2.5

0.0

2.5

5.0

-5.0

-2.5

0.0

2.5

5.0

(A) PDO

(B) SOI

warmer

colder

colder

warmer

Monthly SOI

-3 -2 -1 0 1 2 3

Mon

thly

PD

O

-3

-2

-1

0

1

2

3

Sp03Sp04

Sp05

Su03

Su04

Su05

Su02

Fa03

Fa04

Fa05

Fa02

WARM

COLD

• After Spring 2006: 12 cruises, 3 seasons

• Funding for 1 more year

SOI: Sea Level Pressure (TAHITI – DARWIN)

PDO: Water Temperature (North of 20 o N)

Shifting into a Cold Phase

Conclusions• Marine birds are numerous and conspicuous predators:

“Hotspots”

“Community Structure”

“Range Shifts”

• Concurrent lower-trophic and upper-trophic surveys provide integrated perspective of ecosystem structure and change

Acknowledgements

Streaked

Shearwater

Short-tailed

Shearwater

Sooty

Shearwater

Comparing Different Climate Indices

NOI SOI

PDO + 0.50 - 0.35

• Decoupling between tropics and extra-tropics

• NOI (1951-1999) indicative of La Niña / El Niño events

• NOI suggestive of regime shifts:

• predominantly positive prior to 1977

• variable between 1977 and 1991

• negative from 1992 to 1998

• positive from 1999 to 2001

Schwing et al. (2002)

Monitoring marine bird distributions across the sub-arctic North Pacific using platform of opportunity vessels (2002-2005):Seasonal and Interannual Variability

David Hyrenbach 1, 3, Mike Henry 2, Chris Rintoul 3, Ken Morgan 4, William Sydeman 31 Duke University Marine Laboratory, Beaufort, NC, USA; khyrenba@duke.edu2 Dept. Earth & Ocean Sciences, University of British Columbia, Vancouver, B.C., Canada3 PRBO Conservation Science, Marine Ecology Division, Stinson Beach, CA, USA4 Environment Canada, Institute of Ocean Sciences, Sidney, B.C., Canada

In 2002, we initiated a multi-year monitoring program to survey marine bird and mammal communities from British Columbia (Canada) to Hokkaido (Japan), using the bulk-cargo carrier ‘Skaubryn’ as a platform of opportunity. This project seeks to document spatial gradients in upper-trophic predator assemblages, as well as temporal fluctuations in community structure across the sub-arctic North Pacific Ocean and the southern Bering Sea. We first developed standardized survey techniques using pilot data collected during the summer and fall of 2002. Using these standardized protocols, we have completed nine more surveys since the summer of 2002. Herein, we summarize the seasonal (spring, summer, fall) and interannual (2002 – 2005) distribution patterns of the numerically dominant marine bird and mammal species along a standardized 7,500 km transect. Our replicate surveys have documented clear spatial gradients in faunal distributions, with a particularly striking east to west segregation of three shearwater species: Sooty Shearwaters (Puffinus griseus) dominate off BC and in the Gulf of Alaska, Short-tailed Shearwaters (Puffinus tenuirostris) are numerically dominant in the Southern Bering Sea, and Streaked Shearwaters (Calonectris leucomelas) are most numerous in the Kuroshio – Oyashio current. We have also documented seasonal changes associated with latitudinal shifts of sub-tropical and sub-arctic species, and east-west migration of sub-arctic species (Northern Fulmar Fulmarus glacialis, Black-legged Kittiwake Rissa tridactyla, Least Auklets Aethia pusilla) from Alaskan breeding colonies to distant wintering grounds. This novel synoptic perspective of seabird distributions across the North Pacific underscores the value of cargo vessels as platforms of opportunity. In particular, standardized regional comparisons are required to characterize the response of far-ranging upper-trophic predators and North Pacific marine ecosystems to environmental variability over basin-wide scales.