EASyEASy
The GIS program that simulates habitats,
integrating high quality imagery and analytical tools.

 

Introduction

The TunaScape project, funded by NASA, is a three-dimensional simulation model that couples the circulation of the Eastern Tropical Pacific Ocean (ETPO) to the ecology of the plankton and small nekton communities and ultimately to the movement and population dynamics of the three commercial tuna species (skipjack, yellowfin, and bigeye) of this region. 

This model uses the EASy Software with the Spatial Analysis Option developed by System Science Applications, Inc., for both analysis and display.  It runs at both mesoscale and submesoscale levels and serves as a research tool to answer three sets of questions:

  1. Why is the purse seine fishery, which catches younger fish of all three of the tuna species, clearly defined by the depth of the hypoxic layer and chlorophyll enriched surface waters? How does the circulation in the ETPO explain the formation of a shallow hypoxic layer? To what extent does the compression of diel vertical migration by a shallow hypoxic layer impact the ecology and the cycling of nutrients and exchange of gases in the overlying waters?

  2. What features of circulation lead to tuna aggregation? Are these features apparent at mesoscale (10-100 km) resolution or is submesoscale (<10 km) resolution required?

  3. What will the satellite imagery of sea surface temperature, chlorophyll, and height from the ETOP look like with the new higher resolution sensors such as SWOT and PACE? How can it be used to monitor the tuna fishery?

To answer these questions TunaScape runs a set of models at 18 km and 2.3 km resolution, carefully tuning them to a comprehensive and high-quality database on tuna catch and effort, and running them under differing scenarios.

The main models used in this project are the ECCO-Darwin Model and the TunaScape Tuna and Fishers Model. Below is a diagram of how these models interact to produce results.

ECCO2-Darwin Global Model and Plankton Dynamics
A 3 dimensional, mesoscale and submesoscale biogeochemical simulation running on Pleiades super-computer: currents, T, S, PO4, Fe, O2, PhytoC & CHl
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strong>TunaScape Agent Based and Fishers Model
Population dynamics and movement of tuna schools, purse seine vassel search, movement, & catch within the EASy Geographical Information System.
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Output
A 3-dimensional simulation of the Eastern Tropical Pacific tuna fishery driven by ocean dynamics : currents, temperature, O2, PO4, Fe, phytoplankton carbon, & chlorophyll, tuna school distribution, species, age class, purse vessel distribution, catch and effort.