Pacific herring are an important energy source for species higher in the food web, such as other fish, whales and sea lions. In Prince William Sound, herring once supported a lucrative commercial fishery until species numbers declined dramatically in the early 1990s. This project uses acoustic tags to document the post-spawning related movements of herring to help researchers discover why populations have remained low.

Six Ocean Tracking Network (OTN) arrays are tracking the movements of herring at sites along the Alaskan coast: Hinchinbrook Island, Montague Island, and passages between several adjacent islands. In 2017, the arrays were expanded in Prince William Sound through funding from the Exxon Valdez Oil Spill Trustee Council. The new array was deployed at the east, and west ends of the initial array based on a high concentration of herring detected in these areas from the outermost receivers. 

To date, tracking data have revealed that herring migrate towards the entrance of Prince William Sound after spawning. Additionally, researchers now know that some schools of herring overwinter near the southwest passages of Prince William Sound, while others remain in the Gulf of Alaska until late winter. The arrays have also captured data from five different research projects tracking green sturgeon, Pacific cod, Pacific herring, and salmon shark. These observations are improving the ability to predict herring population dynamics and assess the recovery of this ecologically important species.