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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.

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Seapodym

SEAPODYM


Applications

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 resolution

The evolution in resolution

Pre 2009- 2 degree x month physical forcing (no data assimilation)

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


The evolution in resolution1

The evolution in resolution

2010-2012 - 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

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 analyses skipjack recruitment png

EEZ – Climate – AnalysesSkipjack Recruitment (PNG)

NECC

SEC

SECC


Eez climate analyses enso sp albacore recruitment

EEZ – Climate – AnalysesENSO-SP Albacore recruitment

3

La Nina

Neutral

El Nino

NCEP 1971-2003

SST anomalies - El Nino

  • ZONE 1 (Western)

  • SST decreased, thermocline shallowing

  • ZONE 2 (Central) & ZONE 3 (Eastern)

  • SST increased, thermocline deepening, weaker currents

110W

160W

150E

Longitude

Latitude


Eez sub regional fisheries analyses

EEZ/Sub regional Fisheries Analyses

  • Fishery impacts


Area 1 potential yield skj

Area 1 Potential Yield (SKJ)


Climate change

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.


Seapodym

Skipjack and temperature

The model has a bias in temperature

SKIPJACK LARVAE

(A2 scenario)

Temperature transect at longitude 180°

2nd Exp after T° correction

1st Exp with IPSL-CM4

2000

≠ 4°C

2050

Bias correction

2099


Seapodym

Projecting Climate Change impact

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

SKIPJACK TOTAL BIOMASS

1st Exp with IPSL-CM4

2nd Exp after T° correction

2000

1

2

2050

actual fishing effort

1

average 1990-2000 fishing effort

2

Under thisfishing effort scenario, the stock biomassispredicted to bemainlydriven by larvalrecruitment

2099


Seapodym

Albacore and oxygen

Albacore

(A2 scenario)

Increasing pCO2 could lead to changes of C/N ratio (Oschlies et al. 2008)

With climatological O2

(ie no change from present conditions)

With modeled oxygen

Total biomass

Total biomass

There is still a large uncertainty on O2 modeling while

this is a key variable for tunas

2000

2000

Total biomass

2050

2050

2099

2099


Bigeye a2 scenario

Bigeye (A2 scenario)

First experiment with IPSL CM4

Larvae 2000Larvae 2099Total B 2000Total B 2099

Second experiment (IPSL CM4) with T correction

Larvae 2000Larvae 2099Total B 2000Total B 2099


Summary for climate change analyses

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

Albacore

2000

2099


Climate change summary

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 future tagging really matters

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 tuna

optimal spawning SST


Incorporation of tagging data

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

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.


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