These days, about half of the protein the world’s population eats is from seafood. Staff Writer Erik Stokstad joins host Sarah Crespi to talk about how brand-new biotech and old-fashioned breeding programs are helping keep up with demand, by expanding where we can farm fish and how fast we can grow them.

Sarah also spoke with Jan Claesen, an assistant professor at the Cleveland Clinic’s Lerner Research Institute, about skin microbes that use their own antibiotic to fight off harmful bacteria. Understanding the microbes native to our skin and the molecules they produce could lead to treatments for skin disorders such as atopic dermatitis and acne. Finally, in a segment sponsored by MilliporeSigma, Science’s Custom Publishing Director and Senior Editor Sean Sanders talks with Timothy Cernak, an assistant professor of medicinal chemistry and chemistry at the University of Michigan, Ann Arbor, about retrosynthesis—the process of starting with a known chemical final product and figuring out how to make that molecule efficiently from available pieces.