The article examines the Pacific Decadal Oscillation (PDO), a recurring pattern of ocean-atmosphere climate variability centered over the midlatitudes of the North Pacific basin. Over the past century, the amplitude of this climate pattern has varied irregularly at interannual to interdecadal timescales. The PDO is associated with significant shifts in salmon production regimes in the North Pacific Ocean, affecting coastal sea and continental surface air temperatures, as well as streamflow in major west coast river systems from Alaska to California. The PDO's signature is evident in various climate and ecological systems, including surface air temperature, precipitation, and streamflow. The PDO's positive and negative phases are linked to distinct patterns of oceanic and atmospheric variability, such as cooler-than-average surface waters in the central North Pacific and basin-scale negative anomalies in sea-level pressure. The PDO's influence on salmon production is particularly evident in Alaska, where sockeye and pink salmon catches have shown large fluctuations at interdecadal timescales. The PDO's impact on salmon production is likely due to changes in nearshore marine and estuarine environments, which affect juvenile salmon survival. The PDO's polarity reversals around 1925, 1947, and 1977 have been linked to significant shifts in salmon abundance, with positive phases generally associated with higher salmon catches. The PDO's long-term variability has implications for fishery management, particularly during periods of low productivity.The article examines the Pacific Decadal Oscillation (PDO), a recurring pattern of ocean-atmosphere climate variability centered over the midlatitudes of the North Pacific basin. Over the past century, the amplitude of this climate pattern has varied irregularly at interannual to interdecadal timescales. The PDO is associated with significant shifts in salmon production regimes in the North Pacific Ocean, affecting coastal sea and continental surface air temperatures, as well as streamflow in major west coast river systems from Alaska to California. The PDO's signature is evident in various climate and ecological systems, including surface air temperature, precipitation, and streamflow. The PDO's positive and negative phases are linked to distinct patterns of oceanic and atmospheric variability, such as cooler-than-average surface waters in the central North Pacific and basin-scale negative anomalies in sea-level pressure. The PDO's influence on salmon production is particularly evident in Alaska, where sockeye and pink salmon catches have shown large fluctuations at interdecadal timescales. The PDO's impact on salmon production is likely due to changes in nearshore marine and estuarine environments, which affect juvenile salmon survival. The PDO's polarity reversals around 1925, 1947, and 1977 have been linked to significant shifts in salmon abundance, with positive phases generally associated with higher salmon catches. The PDO's long-term variability has implications for fishery management, particularly during periods of low productivity.