Fish is a major source of protein for many people around the globe. The amount of fish harvested by wild capture fisheries grew from the 1950s to the 1980s, then started to level off in the 1990s, where it has remained stable—at about 80–90 million tonnes of fish annually. This is despite a continual increase in the human population.

For Colleen Petrik, an assistant professor at UC San Diego’s Scripps Institution of Oceanography, that matters when the ocean has limits.

“We have hit the upper limit of how many fish we can catch from the ocean,” says Petrik. “As populations increase but fish catch does not, it means we might not be able to meet the food security needs of all these countries.”

Petrik is working to provide a deeper scientific understanding of the complex ocean ecosystem. Her research is in silico, meaning it is all on the computer. She builds “little simulation oceans,” representing animals, physics, and the processes that link them together, then lets the computer iterate the system forward to see how things change over time. This approach also lets her manipulate parts of the ocean that would be basically impossible to test in the real world.

She connects ocean science to economics as well. Petrik says that in the United States, commercial and recreational fisheries bring in over $300 billion and support over 1.7 million jobs. For Petrik, understanding how marine ecosystems work helps us think more clearly about change and its consequences.

Watch Colleen Pretrik’s presentation on Science and Seafood.