Tagged tuna graphic by Nancy Hulbirt, SOEST Illustration.

PFRP Biology Projects

Assimilating in situ Bioacoustic Data in a Mid-trophic Level Model and its Impact on Predicted Albacore Feeding Habitat in the American Samoa Waters

Progress Reports: FY 2012, FY 2011, FY 2010

Summary

Pacific tuna stocks are facing increasing fishing pressure while they are also under the influence of natural variability and climate change. Nevertheless, the management of these species is still based on annual statistical stock assessment analyses ignoring environmental and climate variability. There is a need for new complementary approaches for management that relies on the development of ecosystem end-to-end models integrating both natural and anthropological effects. Such models, which describe the spatial population dynamics of tuna in relation to their bio-physical environment (e.g., SEAPODYM, a basin-scale ocean model), require key information and parameterization of the forage for tuna, the Mid-Trophic Level (MTL) micronekton, which is one of the less known components of the ocean ecosystem. To optimize the parameters of the basin-scale SEAPODYM MTL sub-model, in situ micronekton biomass should be incorporated at all representative regions within an ocean basin. Therefore, we propose to incorporate existing and new in situ multi-frequency bioacoustic data from four different regions of the Pacific Ocean into SEAPODYM-MTL with a rigorous mathematical method of data assimilation. The incorporation of data from these first four regions is instrumental in the development of SEAPODYM and will lead to massive improvements of the model in the future. Once the parameterization experiments are achieved, the impact of this new parameterization will be tested on the prediction of the feeding habitat and population dynamics of south Pacific albacore tuna in the Samoa region by comparison of model results to in situ data.

Objectives

We propose to use existing and new in situ multi-frequency bioacoustic data from four different regions of the Pacific Ocean to optimize the parameters of the SEAPODYM-MTL model with a rigorous mathematical method of data assimilation. Prior to incorporation into the model, careful analysis of acoustics data will be used to confirm or refine the definition of the vertical layers used in the model, resulting in substantial improvements. Ideally for a basin-scale model, in situ micronekton biomass should be incorporated at all representative regions within the entire Pacific. The incorporation of data from these first four regions is instrumental in the development of SEAPODYM-MTL and will lead to massive improvements of the model in the future. Nonetheless, the development of mathematical code during this project will provide for the first formal evaluation of the MTL model using detailed analysis and comparison between observation and prediction. Once the parameterization experiments for the MTL components are achieved, the impact of these changes will be tested with a new optimization experiment of SEAPODYM to the south Pacific albacore with a focus on the Samoan region.

Funding for this project to be available late 2009.

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Principal Investigators

Dr. Reka Domokos
National Marine Fisheries Service
Pacific Isles Fisheries Science Center
2570 Dole Street
Honolulu, Hawaii 96822 USA
Phone (808) 983-5368
FAX (808) 983-2902
email: Reka.Domokos@noaa.gov

Dr. Patrick Lehodey
Marine Ecosystem Modeling & Monitoring by Satellites (MEMMS)
Spatial Oceanography Division
Collecte Localisation Satellites (CLS)
8-10 rue Hermes
31520 Ramonville, FRANCE
Phone (33) 561-393-770
FAX (33) 561-393-782
email: plehodey@cls.fr

 

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