Striped bass (Morone saxatilis) are a top predator that make annual migrations along the Atlantic coast to forage. Striped bass have rebounded from low numbers in the early 1980s and are now seasonally abundant in many New England estuaries. For these reasons, PIE LTER may provide critical foraging habitat for striped bass. In addition, striped bass could potentially alter trophic structures in estuarine environments. A previous study on striped bass movements in PIE found that: (i) over 50% of tagged fish remained in the estuary for greater than 30 days, (ii) fish were not randomly distributed throughout the estuary, (iii) individual fish used different parts of the estuary (river vs. sound fish), (iv) over 50% of fish tagged the first year of the study returned to PIE the following year, and (v) the majority of seasonal residents were seen in either Long Island Sound or Delaware Bay in winter confirming that these striped bass were part of the coastal migratory stock. In this study, we seek to test the generality of the patterns described above and identify habitat features associated with high and low concentrations of striped bass. In June 2009, we tagged 50 striped bass (400-600 mm TL) in Plum Island Estuary with VEMCO VR13 69 kHz acoustic tags. These tags had nominal ping rates of 120 seconds and an expected battery life of 365 days. To track striped bass habitat use within PIE and movements into and out of the estuary, we installed gates at the mouths of the four major tidal rivers feeding into PIE, and the mouth Plum Island Sound. These gate receivers will record striped bass presence within a radius of 600 m every 1 to 3 minutes from June through November. To assess estuary use patterns at a smaller scale, one week per month, we recorded fish presence or absence at 40 locations that were regularly distributed throughout PIE. Presence or absence was recorded for 15 minutes at both ebbing and flooding tides. Via remote sensing, these sites were categorized as 7 creek mouths or confluences, 7 drop-offs, 7 structure, and 19 combinations of two or more of the above. Velocity, depth, and salinity were sampled concurrent with fish detections. We will continue to track fish throughout October, 2010 to assess if within PIE, striped bass are clustered, if individual contingents use specific locations, and what physical characteristics are associated with striped bass use of the estuary. These data will provide insights into the role of PIE in the migration and potential growth of an important fish predator. This study will also set the stage for future examination of how top predators affect prey and pathways by which biogeochemical changes in the estuary may get transferred to higher trophic levels.