To understand how Puget Sound has changed, we first must understand how it used to be. Unlike most major estuaries in the U.S. — and despite the abundance of world-class oceanographic institutions in the area — long-term monitoring of Puget Sound fish populations did not exist until 1990. Filling in this missing information is essential to establishing a baseline that would provide context for the current status of the marine ecosystem, and could guide policymakers in setting more realistic ecosystem-based management recovery targets.