Striped Bass Contingent Behavior and Migration Corridors in the Lower Hudson River Estuary

Despite its highly industrialized and urbanized setting, the lower Hudson River Estuary is an important habitat for striped bass Morone saxatilis, contributing to important fisheries throughout the Hudson River, NY Harbor, and well beyond in coastal Atlantic waters. Based upon previous otolith chemistry and telemetry research we hypothesized that the composition of lower estuary aggregations of striped bass changed seasonally and was comprised of three separate contingents: 1. Lower Hudson River Estuary-New York Harbor fish that resided there for most of the year; 2. Upper Hudson River fish that descended during winter months; and 3. Coastal migrants that transited through the harbor during spring as they moved into and out of the Hudson River as part of their anadromous spawning migrations.  Such contingent behaviors can shape how population segments respond to exploitation and environmental stressors such as pollution and harbor dredging.   In the fall of 2009 and spring of 2010 we implanted acoustic telemetry transmitters in striped bass Morone saxatilis (n = 75) sampled in the  Hudson River Estuary.  Tagged fish were monitored in the lower Hudson River and New York Harbor using acoustic receiver ‘curtains’ at points of entry and egress and in other locations within the river.  The data collected in the Hudson River was augmented by  other researchers’ arrays.  Fish tagged in the Hudson River were detected as far north as the Kennebec River in Maine and as far south as the Chesapeake Bay.  Results indicate that contingent behaviors showed distinct seasonal patterns of habitat use across the Hudson River, NY Harbor, and coastal regions.  Further individuals precisely homed to specific areas at the same time year-to-year.  Fish assumed to be of the Hudson River Estuary contingent differed in that they displayed a variety of inhabitance behaviors and several fish appeared to belong to the Delaware River population.  Certain corridors appeared to be favored as points of egress and entry into the NY Harbor and patterns of use by the three contingents varied seasonally.