SEAPODYM

Applications

• Understand Tuna Climate interactions.• Forecast effects on climate change on tuna

distribution and abundance.• Capture meso-scale distribution information

which allows for more EEZ level estimates of distribution and abundance.

• Assistance for national and sub-regional tuna management planning.

The evolution in resolutionPre 2009- 2 degree x month physical forcing (no data assimilation)

2009-2010 2 degree x month physical forcing (with data assimilation)

The evolution in resolution2010-2012 - 1 degree x month physical forcing (with data assimilation)

2012 - ¼ degree x week physical forcing (with data assimilation)

December 2007 SODA 1°

06 December 2007 GLORYS ¼°

Improved Resolution

• Taken a number of years for the physical forcing data to become available.

• Need 1 degree resolution for EEZ level analyses otherwise results barely differ from regional averages.

• Optimised 1 degree models for skipjack, bigeye, south pacific albacore and swordfish.

• New ¼ degree data has become available in 2013 which corrects equatorial anomalies.

EEZ – Climate – AnalysesSkipjack Recruitment (PNG)

SEC

SECC

NECC

1

1

Month 1

140E 150E 160E 170E

15S

10S

5S

05N

1

1

Month 2

140E 150E 160E 170E

15S

10S

5S

05N

1

1

Month 3

140E 150E 160E 170E

15S

10S

5S

05N

1

1

Month 4

140E 150E 160E 170E

15S

10S

5S

05N

1

1

Month 5

140E 150E 160E 170E

15S

10S

5S

05N

1

1

Month 6

140E 150E 160E 170E

15S

10S

5S

05N

1

1

Month 7

140E 150E 160E 170E

15S

10S

5S

05N

1

1

Month 8

140E 150E 160E 170E

15S

10S

5S

05N

1

1

Month 9

140E 150E 160E 170E

15S

10S

5S

05N

1

1

Month 10

140E 150E 160E 170E

15S

10S

5S

05N

1

1

Month 11

140E 150E 160E 170E

15S

10S

5S

05N

1

1

Month 12

140E 150E 160E 170E

15S

10S

5S

05N

0 20 40 60 80 100

Primary Production (mgC/m2/day)

150 200 250

01

23

45

6

a

c

EEZ – Climate – AnalysesENSO-SP Albacore recruitment

150 200 250

01

23

45

6

d

f

10 15 20

01

23

45

6

e

f

La Nina

Neutral

El Nino

150 200 250

01

23

45

6

x

z

10 15 20

01

23

45

6

y

z

10 15 200

12

34

56

b

c

Longitude Latitude150E 160W 110W

ZONE 2 (Central) & ZONE 3 (Eastern)•SST increased, thermocline deepening, weaker currents

ZONE 1 (Western)• SST decreased, thermocline shallowing

3

NCEP 1971-2003

SST anomalies - El Nino

EEZ/Sub regional Fisheries Analyses

• Fishery impacts

Area 1 Potential Yield (SKJ)

0

2

4

6

8

10

12

0

10,000

20,000

30,000

40,000

50,000

60,000

0 10,000 20,000 30,000 40,000 50,000

Equi

libri

um C

PUE

(ton

nes /

day

)

Equi

libri

um c

atch

(ton

nes)

Equilibrium Effort (days)

Average catch Average CPUE

Climate Change

• Predicting the past to understand the future.• IPCC has developed an ensemble of models

predicting future climate scenarios under different atmospheric assumptions

• Only 1 (IPSL) has been coupled with the PISCES model to predict future primary production.

• Optimised the model with historical data and then simulate into the future under the A2 scenario defined by IPCC.

Skipjack and temperature

SKIPJACK LARVAE(A2 scenario)

2000

2050

2099

1st Exp with IPSL-CM4 2nd Exp after T° correction

≠ 4°C

Temperature transect at longitude 180°

The model has a bias in temperature

Bias correctionBias correction

Projecting Climate Change impact

SKIPJACK TOTAL BIOMASS

2000

2050

2099

1st Exp with IPSL-CM4 2nd Exp after T° correction

(Both simulations used average 1990-2000 fishing effort to project fishing impact)

1 2

12

actual fishing effortaverage 1990-2000 fishing effort

Under this fishing effort scenario, the stock biomass is predicted to

be mainly driven by larval recruitment

Total biomass

Albacore (A2 scenario)

2000

2050

2099

Albacore and oxygen

With modeled oxygen

Increasing pCO2 could lead to changes of C/N ratio

(Oschlies et al. 2008)

There is still a large uncertainty on O2 modeling whilethis is a key variable for tunas

2000

2050

2099

Total biomass

With climatological O2 (ie no change from present conditions)

Total biomass

Bigeye (A2 scenario)

First experiment with IPSL CM4 Larvae 2000 Larvae 2099 Total B 2000 Total B 2099

Second experiment (IPSL CM4) with T correction Larvae 2000 Larvae 2099 Total B 2000 Total B 2099

Summary for Climate Change Analyses• Results are consistent for the 3 species with an eastwards shift

in spawning and forage habitat.• Currently assuming no adaptation to changing temperatures

with SST >33-34°C estimated to be a threshold for spawning of tropical tunas.

Skipjack Bigeye

2000

2099

Albacore

Climate Change Summary• New simulations with temperature corrected forcing predict a lower

skipjack biomass and a decreasing trend after the 2070’s, driven by large extension of unfavourable equatorial spawning grounds.

• Application to albacore is highly sensitivity to O2, for which the biogeochemical models are still unclear.

• Parameter estimation using the IPCC models is adequate but inferior to ocean models with data assimilation. The climate models lack historical variability.

• Climate model ensemble simulations could help to solve the problem of bias.

• Ideally we would use climate model simulation with realistic historical variability (ENSO, PDO, NAO). These may be available in the near future.

• Climate projections for 10-15 years into the future probably more tangible for current fisheries planning.

Immediate FutureTagging really matters

• All optimisations so far have struggled to estimate movement.• Integrating conventional tagging data in the optimization

approach improves movement estimation.• Times series of tagging data extremely beneficial.

movement

threshold value of dissolved oxygen

optimal temperature for oldest tunaoptimal spawning SST

Incorporation of tagging data

• Preliminary (2 years of tagging data)

Predicted distributions of skipjack tuna in g/m2 (both young and adult life stages) as the result of experiments conducted with different likelihood composition: (left) including CPUE and length frequencies components only; (right) CPUE, LF and Tagging data components.

Summary• 1 degree models that allow meaningful EEZ and sub-

regional extraction of information.• Prepare national climate profiles. • Prepare climate change analyses within the IPCC

framework.• Assist sub-regional and SPC members with tuna

management planning.• New ¼ degree physical forcing available in 2013 that

will also allow simulation to end 2012. • Full incorporation of PTTP tagging data to better

parameterise movement.