Tuna, fisheries and Climate variability

Tuna distribution and abundance have been shown to be sensitive to environmental variability. In particular, the El Niño Southern Oscillation (ENSO) appears to have important consequences both for spatial distributions and migrations of the tuna populations and for their level of recruitment and biomass. Interestingly, the signal appears to be opposite according to the species, e.g., an El Niño event would have a positive influence on the recruitment of skipjack while the effect would be negative on the albacore. In addition, the interannual signal presents a correlation with the Pacific Decadal Oscillation (PDO), leading to two different regimes characterized by higher intensity and frequency of either El Niño or La Niña events.

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Oceanic Fisheries and Climate Change Project (OFCCP)

The ultimate goal of the project is to conduct simulations with ecosystem models that include the main tuna species, using an input data set predicted under a scenario of climate change induced by greenhouse warming. This should lead to the first tentative understanding how greenhouse warming will affect, at the ocean and global scales, the abundance and productivity of marine populations in the pelagic ecosystem,  focusing on the major exploited species and fisheries, by a real coupling between atmospheric, oceanic, chemical and biological processes. Potential feedbacks from the changes in the pelagic ecosystem, and socio-economical consequences will be investigated to propose adaptation measures for the future.

[more on OFCCP...]
[GLOBEC web site...]

Modeling

To explore the underlying mechanisms by which the environmental variability affects the pelagic ecosystem and tuna populations, a spatial environmental population dynamics model (SEPoDyM) is developed. The model is a basin-scale, 2D coupled physical-biological interaction model, combining a forage (prey) production model with an age structured population model of targeted (tuna predator) species and their fisheries. The model contains environmental and spatial components used to constrain the movement and the recruitment of tuna.

[more on SEPoDyM...]