Timing of entry, distribution, Timing of entry, distribution, and condition of chum salmon and condition of chum salmon

juveniles juveniles in western Alaska in western Alaska

Nicola Hillgruber Nicola Hillgruber Christian E. ZimmermanChristian E. Zimmerman

Sean E. BurrilSean E. Burril

OutlineOutline

► Introduction & BackgroundIntroduction & Background►MethodsMethods►ResultsResults

Fish catches and timing of Fish catches and timing of outmigrationoutmigration

Distribution Distribution Size and conditionSize and condition Otolith microchemistryOtolith microchemistry

►ConclusionsConclusions

MethodsMethods

Kuskokwim Bay, western Kuskokwim Bay, western AlaskaAlaska

Quinhagak

Eek

Bethel

Ishkowik River

Kwethluk River

Sampling StationsSampling Stations

0 20 4010 Kilometers

9

8

7

6

5

4

3

2

1

21

20

19

18

17

16

15

14

13

12

11

10

MethodsMethods

Sampling TripsSampling Trips

20032003 20042004

June 23-25June 23-25 Week 1: May 16-22Week 1: May 16-22

July 24-26July 24-26 Week 2: May 23-29Week 2: May 23-29

August 26-30August 26-30 Week 3: May 30-Week 3: May 30-June 5June 5

Week 4: June 6-12Week 4: June 6-12

ResultsResults

Fish abundance Fish abundance

and timing of outmigrationand timing of outmigration

Catch summary in 2003 and 2004Catch summary in 2003 and 2004

Species 2003 2004 Total Fork length [mm]

Oncorhynchus keta 68 1,245 1,313 31-66

Oncorhynchus kisutch 1 200 201 70-170

Oncorhynchus tshawytscha 5 50 55 78-125

Oncorhynchus nerka 0 38 38 63-124

Oncorhynchus gorbuscha 4 76 80 32-53

Ammodytes hexapterus 0 739 739

Clupea pallasii 2,035 1 2,036

Osmeridae 1,810 22,778+

24,588

Gasterosteidae 1,117 1,432 2,549

Others 10 104 114

Mean CPUE (Mean CPUE (±SE)±SE) of juvenile chum of juvenile chum salmon at the head of Kuskokwim Bay salmon at the head of Kuskokwim Bay

(station 1-3) (station 1-3)

0

1

2

3

4

5

6

May-19 May-26 Jun-2 Jun-9 Jun-24 Jul-25 Aug-27

Week

Ln

(CP

UE

+1

) 2003

2004

0

1

2

3

4

May-19 May-26 Jun-2 Jun-9 Jun-24 Jul-25 Aug-27

0

1

2

3

4

May-19 May-26 Jun-2 Jun-9 Jun-24 Jul-25 Aug-27

0

1

2

3

4

May-19 May-26 Jun-2 Jun-9 Jun-24 Jul-25 Aug-27

0

1

2

3

4

May-19 May-26 Jun-2 Jun-9 Jun-24 Jul-25 Aug-27

Mean CPUE for juvenile salmonids Mean CPUE for juvenile salmonids at the head of Kuskokwim Bay at the head of Kuskokwim Bay

(station 1-3)(station 1-3)

2004 2003

Coho Pink

Chinook Sockeye

ResultsResults

Environmental factors and Environmental factors and juvenile chum salmon juvenile chum salmon

distributiondistribution

SST and SSS in 2004SST and SSS in 2004

6/06-6/12

5/16-5/22

Legend

6 - 7

7 - 8

8 - 9

9 - 10

10 - 11

11 - 12

12 - 13

13 - 14

14 - 15

15 - 16

Legend

0 - 5

5 - 10

10 - 15

15 - 20

20 - 25

25 - 30

Temperature

Salinity

Surface density [mSurface density [m-3-3] of small copepod in ] of small copepod in 20042004

Legend

2

3 - 75

76 - 120

121 - 222

223 - 9000

5/16-5/22

5/23-5/29

5/30-6/05

6/06-6/12

Chum salmon CPUE in 2004Chum salmon CPUE in 2004

E

EE

E

E

E

E

E

E

E

E

E

E

E

E

E

E

E

E

E

E

E

E

E

E

E

E

E

E

E

E

E

Legend

E 0.000000

0.000001 - 0.010000

0.010001 - 0.100000

0.100001 - 1.000000

1.000001 - 10.000000

10.000001 - 30.000000

No Chum

0 - 0.01

0.01 - 0.1

0.1 - 1.0

10.0 – 30.0

1.0 – 10.0

5/16-5/22

5/23-5/29

5/30-6/05

6/06-6/12

Chum salmon CPUE by SSSChum salmon CPUE by SSS

Week 1

0 5 10 15 20 25 30 35

ln C

PU

E +

1

0

2

4

6

8

10

Week 2

0 5 10 15 20 25 30 35

ln C

PU

E +

1

0

2

4

6

8

10

Week 3

0 5 10 15 20 25 30 35

ln C

PU

E +

1

0

2

4

6

8

10

Week 4

Sea Surface Salinity

0 5 10 15 20 25 30 35

ln C

PU

E +

1

0

2

4

6

8

10

ResultsResults

Size and conditionSize and condition

Weight and length of chum salmon Weight and length of chum salmon juvenilesjuveniles

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

May 16-22 May 23-29 May 30-June 5 June 6-12

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

June 23-25 July 24-26 August 26-30

0

10

20

30

40

50

60

May 16-22 May 23-29 May 30-June 5 June 6-12

0

10

20

30

40

50

60

June 23-25 July 24-26 August 26-30

Fork Length [mm]Fork Length [mm]

Weight [g]Weight [g]20042004 20032003

18 62 48 162 356

FL = 173.1 mm

(Aug/Sept)Farley et al.

0

Energy content by size and month in Energy content by size and month in 20042004

4500

4700

4900

5100

5300

5500

5700

Takotna 30-39 40-49 50-59 60-69 Shelf

cal/g

dry

we

igh

t

May 2004

June 2004

23 59

Aug/Sept(Farley pers.

comm.)

815 river km

4500

4700

4900

5100

5300

5500

5700

30-39 40-49 50-59 60-69

cal/g

dry

we

igh

t

May 2004

June 2004

58 32 21 58111 3 69

0

ResultsResults

Otolith microchemistryOtolith microchemistry

Determination of saltwater entry for Determination of saltwater entry for Kuskokwim Bay chum and Chinook Kuskokwim Bay chum and Chinook

salmonsalmon

Distance from primordium (microns)

0 100 200 300 400 500 600

Sr/

Ca

0.0000

0.0005

0.0010

0.0015

0.0020

0.0025

0.0030

Chum salmonChinook salmonCollected at

SSS=12

ConclusionsConclusions

► Chum emigration peaked in early/middle Chum emigration peaked in early/middle JuneJune

► Juveniles followed the river plume before Juveniles followed the river plume before moving into the bay moving into the bay

► Length and weight increased with season Length and weight increased with season

► Condition decreased with size, season, Condition decreased with size, season, SSTSST

► No distinct saltwater entry signal for chum No distinct saltwater entry signal for chum salmon juvenilessalmon juveniles

AcknowledgementsAcknowledgements

► Mikhail BlikshteynMikhail Blikshteyn

► Johnny ZutzJohnny Zutz

► Jim PeacockJim Peacock

► Bill WiebeBill Wiebe

► Wendy WhelanWendy Whelan

► Switgard DuesterlohSwitgard Duesterloh