Anticipating Fluctuations of Bigeye Tuna in the Pacific Ocean From Three-Dimensional Ocean Biogeochemistry

Ocean forecasting (whether it takes place over weeks, or years) can make significant contributions to achieving effective management of living marine resources in a changing ocean. Most applications rely on indirect proxies, however, often measured at the ocean surface and lacking a direct mechanistic link to the dynamics of marine populations.

Here, we take advantage of three-dimensional, dynamical reconstructions and forecasts of ocean biogeochemistry based on a global Earth system model to hindcast and assess the capacity to anticipate fluctuations in the dynamics of bigeye tuna (Thunnus obesus Lowe) in the Pacific Ocean during the last six decades. We reconstructed spatial patterns in catch per unit effort (CPUE) through the combination of physiological indices capturing both habitat preferences and physiological tolerance limits in bigeye tuna.

Our analyses revealed a sequence of four distinct regimes characterized by changes in the zonal distribution and average CPUE of bigeye tuna in the Pacific Ocean. Decade-long forecast experiments further suggested that forecasts of three-dimensional biogeochemical information might enable anticipation of fluctuations in bigeye tuna several years ahead. 

Taboada FG, Park JY, Muhling BA, Tommasi D, Tanaka KR, Rykaczewski RR, Stock CA, Sarmiento JL. 2023. Anticipating fluctuations of bigeye tuna in the Pacific Ocean from three-dimensional ocean biogeochemistry. Journal of Applied Ecology, 00, 1? 17.  https://doi.org/10.1111/1365-2664.14346.