This book details the effects of climate variability on small pelagic fish and their ecosystems and fisheries. Particularly abundant in coastal upwelling regions off the west coasts of the Americas and Africa, off Japan, and in the North East Atlantic, the stocks of these fish fluctuate greatly over the timescale of decades, with large ecological and economic effects. This book describes the nature and cause of these fluctuations, and their consequences. It outlines results from paleo-oceanographic studies, showing that similar fluctuations have also occurred over the past two millennia. The potential effects of future climate change, both natural and anthropogenic, on stocks and fisheries, are considered. The book concludes by recommending the continued international study and assessment of small pelagic fish in order to best inform management and policy under a changing climate. It is written for research scientists, academics, and policy makers in fisheries, oceanography, and climate change.