September 26, 2011

Chinook Needs of Southern Resident Killer Whales & Ratios of Chinook Available : Whale Needs Alison Agness - Fishery Biologist NOAA Fisheries, Northwest Region

2

The Whales’ Chinook Food Energy Needs

NMFS uses four pieces of scientific information to estimate the whales’ energy needs from Chinook: (1) Their estimated metabolic requirements, (2) The population age/sex structure and abundance, (3) Estimated time spent in inland and coastal waters of

their range, and (4) How much of their metabolic requirements would

ideally be met by Chinook, based on available data regarding percent Chinook in their diet.

3

Estimated Metabolic Requirements

0

50,000

100,000

150,000

200,000

250,000

300,000

Dai

ly P

rey

Ener

gy R

equi

rem

ents

(kca

l/day

)

Age and Sex Classes (Noren 2011)

Max DPER

Min DPER

• Review Noren (2011) results:

4

Population Age/Sex Structure and Abundance

• Known age and sex of all individuals.*

*Annual census by The Center for Whale Research

0

2

4

6

8

10

12

14

16

Num

ber o

f Wha

les

Age and Sex Class (Noren 2011)

J

K

L

5

Daily Prey Energy Requirements by Pod

• Multiplied number of whales per pod and class by both Min and Max DPER.

• Summed the resulting DPER values across class categories per pod.

0

1,000,000

2,000,000

3,000,000

4,000,000

5,000,000

6,000,000

7,000,000

8,000,000

J K L

Tota

l DPE

R N

eeds

(kca

l/day

)

Pod

Total DPER Needs (kcal/day) Min

Total DPER Needs (kcal/day) Max

6

Estimated Time Spent in Inland and Costal Waters

0

5

10

15

20

25

30 Av

erag

e D

ays/

Mon

th

(Han

son

and

Emm

ons

2010

)

Month

Inland Waters

Jpod Kpod Lpod

0

5

10

15

20

25

30

Aver

age

Day

s/M

onth

(H

anso

n an

d Em

mon

s 20

10)

Month

Coastal Waters

Jpod Kpod Lpod

7

Monthly Energy Requirements by Pod & Location

• Multiplied total pod DPER by number of days per month and location.

0 20,000,000 40,000,000 60,000,000 80,000,000

100,000,000 120,000,000

Ener

gy R

equi

rem

ents

(k

cal)

Month

J pod, Inland waters

Max Min

0 20,000,000 40,000,000 60,000,000 80,000,000

100,000,000 120,000,000 140,000,000

Ener

gy R

equi

rem

ents

(k

cal)

Month

J pod, Coastal waters

Max Min

8

Summarized by Pod and FRAM Time Periods

0 50,000,000

100,000,000 150,000,000 200,000,000 250,000,000 300,000,000 350,000,000 400,000,000 450,000,000

Oct

-Apr

il

May

-Jun

e

July

-Sep

t

Oct

-Apr

il

May

-Jun

e

July

-Sep

t

Oct

-Apr

il

May

-Jun

e

July

-Sep

t

J K L Ener

gy R

equi

rem

ents

(kca

l)

FRAM Time Period by Pod

Inland waters Min Max

0 200,000,000 400,000,000 600,000,000 800,000,000

1,000,000,000 1,200,000,000 1,400,000,000 1,600,000,000

Oct

-Apr

il

May

-Jun

e

July

-Sep

t

Oct

-Apr

il

May

-Jun

e

July

-Sep

t

Oct

-Apr

il

May

-Jun

e

July

-Sep

t

J K L Ener

gy R

equi

rem

ents

(kca

l)

FRAM Time Period by Pod

Coastal waters Min Max

9

Summarized for the Whole Population

0

500,000,000

1,000,000,000

1,500,000,000

2,000,000,000

2,500,000,000

3,000,000,000

Oct-April May-June July-Sept Oct-April May-June July-Sept

Inland Coastal

Ener

gy R

equi

rem

ents

(kca

l)

FRAM Time Period by Location

Min

Max

10

Metabolic Requirements Ideally Met by Chinook -Methods

Methods: Multiplied % Chinook by the population energy-requirements for each FRAM time period and location.

• % Chinook: Used scale and tissue samples from Hanson et al. 2010 to compute % Chinook in diet per FRAM time period.

• Oct-April estimate: no data from Feb-April. Used a weighted mean of months with data (Oct-Jan; 24%*4) and months without data (represented Feb-April with next available data from May-June; 85%*3).

• Assumption: Same % Chinook per FRAM time period in both inland and coastal waters.

Time period % Chinook

Oct-April 58 May-June 85 July-Sept 91

11

Metabolic Requirements Ideally Met by Chinook- Results

0

500,000,000

1,000,000,000

1,500,000,000

2,000,000,000

2,500,000,000

Oct-April May-June July-Sept Oct-April May-June July-Sept

Inland Coastal

Ener

gy R

equi

rem

ents

(k

cal)

FRAM Time Period and Location

Non-Chinook Min Chinook Min

0

500,000,000

1,000,000,000

1,500,000,000

2,000,000,000

2,500,000,000

3,000,000,000

Oct-April May-June July-Sept Oct-April May-June July-Sept

Inland Coastal

Ener

gy R

equi

rem

ents

(k

cal)

FRAM Time Period and Location

Non-Chinook Max

Chinook Max

Minimum

Maximum

12

Ratios of Chinook Available Compared to the Whales Needs - Methods

• Ratio = Prey Available (kcal) / Whale Needs (kcal) • Specific to FRAM time period and location.

• Indicate that Chinook available is greater than the whales’ needs by the magnitude of the value.

• Computed ratios where fisheries are closed and open for comparative purposes. • All U.S. and Canadian Fishing Open • All Open Except Puget Sound Fishing • Only Canadian Fishing Open • All U.S. and Canadian Fishing Closed

• Considered ratios for other marine predators and systems to provide context.

• New: Consider the relative influence of select parameters on the ratio estimates to highlight model sensitivities.

13

Ratios of Chinook Available Compared to the Whales Needs – Coastal Results

15 20 25 30 35 40 45 50 55 60 65

0 1 2 3 4 5

Aver

age

Rat

io

Fishing Scenario

May-June

5

10

15

20

25

0 1 2 3 4 5

Aver

age

Rat

io

Fishing Scenario

July-Sept

5

10

15

20

25

30

35

0 1 2 3 4 5

Aver

age

Rat

io

Fishing Scenario

Oct-April

Fishing Scenario: 1 = All U.S, and Canadian Fishing Open

2 = All U.S. and Canadian Fishing Open Except Puget Sound

3 = Only Canadian Fishing Open

4 = All U.S. and Canadian Fishing Closed

14

Ratios of Chinook Available Compared to the Whales Needs – Coastal Results, Cont.

0 5

10 15 20 25 30 35 40 45 50 55 60 65 70

Rat

io

Year

All U.S. and Canadian Fishing Open

0 5

10 15 20 25 30 35 40 45 50 55 60 65 70

Rat

io

Year

All U.S. and Canadian Fishing Except Puget Sound

0 5

10 15 20 25 30 35 40 45 50 55 60 65 70

Rat

io

Year

Only Canadian Fishing Open

0 5

10 15 20 25 30 35 40 45 50 55 60 65 70

Rat

io

Year

All U.S. and Canadian Fishing Closed

Oct-April May-June July-Sept

15

Ratios of Chinook Available Compared to the Whales Needs – Inland Results

Fishing Scenario: 1 = All U.S, and Canadian Fishing Open

2 = All U.S. and Canadian Fishing Open Except Puget Sound

3 = Only Canadian Fishing Open

4 = All U.S. and Canadian Fishing Closed

4

5

6

7

8

0 1 2 3 4 5

Aver

age

Rat

io

Fishing Scenario

Oct-April

5 6 7 8 9

10 11 12 13

0 1 2 3 4 5

Aver

age

Rat

io

Fishing Scenario

May-June

3

4

5

6

7

8

9

10

11

0 1 2 3 4 5

Aver

age

Rat

io

Fishing Scenario

July-Sept

16

Ratios of Chinook Available Compared to the Whales Needs – Inland Results, Cont.

0

2

4

6

8

10

12

14

Rat

io

Year

All U.S. and Canadian Fishing Open

0

2

4

6

8

10

12

14

Rat

io

Year

All U.S. and Canadian Fishing Open Except Puget Sound

0

2

4

6

8

10

12

14

Rat

io

Year

Only Canadian Fishing Open

0

2

4

6

8

10

12

14

Rat

io

Year

All U.S. and Canadian Fishing Closed

Oct - April May- June July-Sept

17

Ratios for Other Marine Predators and Systems Ratios of prey to predators in four North Pacific ecosystem models. Predators included are cetaceans with fish comprising more than 25% of their diet (Kaplan 2011).

Region Predator

Weighted Prey Ratios by diet composition

only most abundant prey items that collectively sum to 95% of diet

excluding individual prey items <5% of diets

Northern California Current baleen whalesa 24.2 23.9 23.9

Northern California Current orcasb 124.4 122.2 119.6

Northern California Current sperm whalesc 20.0 19.5 19.0

Northern California Current toothed whalesd 14.3 14.3 14.1

Northern British Columbia toothed whalese 3.1 3.1 2.9

Eastern Bering Sea toothed whalesf 30.3 30.1 21.6

Western Bering Sea toothed whalesg 6.0 6.0 5.8

18

Relative Influence of Parameters on the Ratio Estimates

Example: 2008, All U.S. and Canadian Fishing Open, Inland Waters, July – Sept • Start with set values for 2 parameters and a model

decision-rule – • DPER level (Max); Selectivity Function (NOAA-FRAM

model); and After Natural Mortality step of FRAM • Ratio = 4.77

• Vary DPER level (Min) • Ratio = 5.73

• Vary Selectivity Function • Ford-FRAM, Ratio = 3.34 • No Selectivity, Ratio = 18.22

• Vary decision rule for natural mortality • Before natural mortality, Ratio = 5.56

19

Relative Influence of Parameters on the Ratio Estimates, Cont. • Whale Needs:

• Number of whales in the population • Age/Sex distribution • Days spent in each location • DPER level • % Chinook in diet

• Chinook Availability: • Selectivity function • Inclusion/exclusion of FRAM-estimated natural mortality • Assumptions about the contribution of coastal-origin stocks

to inland availability and visa versa (i.e., only those caught were available)

20

Potential New Approaches for Consideration

• Use a Monte Carlo approach to estimate ratios - incorporate variability in each parameter and decision-rule and test parameter sensitivity.

• Further investigate ratios for other predators and systems.

• Other thoughts?