All of the living marine resources that we enjoy, whether as food or for their intrinsic appeal, depend ultimately on the base of the food chain, the plankton. Scientists have long recognized that the open ocean is not an unchanging environment. Currents, topography, and climate combine to create variabilities in time and space in the physical, chemical, and biological characteristics of the oceans. Plankton have limited control over their movements and thus are subjected to the local conditions that prevail. These conditions, in turn, determine where various types of planktonic organisms occur and how fast and abundantly they grow. In this way, ocean climate changes are transferred up the food chain to the fish, marine mammals, and seabirds that are, to us, the most prominent product of the marine ecosystem. To understand and predict changes in living marine resources under future climate-change and ocean-use scenarios, we need information about the physical environment and the plankton. The question is how best to measure and monitor these properties over thousands of kilometers. Satellites have gone a long way toward enabling a wide view of surface ocean characteristics such as temperature, ocean color, sea-surface height, and the amount of phytoplankton (plant plankton), but zooplankton (animal plankton) cannot yet be viewed from space. Research ships cost a significant amount of money to operate, and any kind of comprehensive spatial coverage of the North Pacific Ocean plankton would be prohibitively expensive and time-consuming. When scientists at the North Pacific Marine Science Organization (PICES) were considering this problem, they turned to the Sir Alister Hardy Foundation for Ocean Science (SAHFOS) and the continuous plankton recorder (CPR) survey for help.