Life-history model of sardine-anchovy cycles
According to the Food and Agriculture Organization of the United Nations, the catch of anchovy reached its peak in the 1970s, dramatically decreased in the 1980s, and recovered to the previous level in the 1990s. In contrast, the catch of sardine began to grow in the 1970s, reached its peak in the 1980s, and has dropped sharply in the 1990s.
This oscillatory phenomenon is known as sardine-anchovy cycles. Both anchovy and sardine serve as major food resources around the globe, so their cycling strongly impacts seafood supplies, fisheries economics, and coastal communities. Recent studies discovered that fluctuations in air temperature and ocean temperature were similar, in terms of phase and duration, to the oscillatory catches, suggesting that sardine-anchovy cycles are primarily driven by climatic changes.
In addition, interactions among these species, and also among cohorts within each species, have been suggested to contribute to the cycles. In general, however, the causal origin of sardine-anchovy cycles remains open, and no model exists yet to describe these cycles. My research will therefore focus on developing a simple life-history model of the two species that can reproduce this globally observed phenomenon. In this model, I will consider the following factors: (1) climatic change, (2) interspecific interactions, (3) intraspecific cohort dynamics, (4) life-history evolution, and – time permitting – (5) spatial range dynamics. In collaboration with the Korean National Fisheries Research and Development Institute, I will calibrate the developed model with empirical data and with other information available in the literature. It is hoped that this work will help to reveal the mechanisms that are causing the observed long-term cycles, and thus contribute to a better understanding of factors influencing the sustainable exploitation of living marine resources.