Phytoplankton are the foundation of ocean life, providing the energy that supports nearly all marine species. Levels of phytoplankton in an ocean area may seem like a good predictor for the amount of fish that can be caught there, but a new study by Nereus Program researchers finds that this relationship is not so straightforward.“Using measurements of phytoplankton growth at the base of the food web to estimate the potential fish catch for different parts of the ocean has long been a dream of oceanographers,” says author Ryan Rykaczewski, Assistant Professor at University of South Carolina and Nereus Program Alumnus. “We know that these two quantities must be related, but there are several steps in the food chain that complicate the conversion of phytoplankton growth to fish growth.”