Timothy Essington, a professor with the University of Washington’s School of Aquatic and Fishery Sciences, is a marine ecologist and mathematical modeler who is interested in understanding how human activities shape marine ecosystems and the ecosystem services we derive from them. The ecosystem approach to fisheries management has been widely promoted as a means to foster more sustainable management of marine resources by protecting vital and valued ecosystem functions. A central tenet of this approach is that fisheries decisions can be improved through a more holistic view that considers broader ecosystem impacts of fishing, and thereby directly considers trade-offs among conflicting demands for valued services that ecosystems provide. Essington’s Pew fellowship project worked to advance methods for valuing forage fish in marine ecosystems by developing tools to measure trade-offs between the essential ecosystem services they supply and their commercial value as commodities to be caught. In collaboration with an economist, Essington considered both economic and biological data and models for forage fish and squids, which play a similar ecological role as forage fish. He then applied the tools he developed to real fishery ecosystems. Essington’s project provided a comprehensive empirical demonstration of the ecological and economic impacts of forage fish and squid fisheries. It also provided new quantitative methods that may be adopted by managers for identifying, measuring, and resolving ecological trade-offs in fisheries. To learn more about Essington, visit his bio online: https://fish.uw.edu/faculty/tim-essington.