Factors Influencing the Coastal Movements of Atlantic Sturgeon in the Mid-Atlantic and Along the Eastern Seaboard of North America

Recently Atlantic sturgeon (Acipenser oxyrinchus oxyrinchus) were proposed for listing under the ESA with a final ruling due to be released in October 2011.  Once supporting a tremendous caviar and flesh fishery, Atlantic sturgeon populations suffered from severe overharvest and habitat destruction beginning in the late 19^th century and have since shown little recovery.  In order for managers to afford proper protection potential impacts need to be assessed.  Bycatch and mortality impacts of dredging, sand mining for beach replenishment, and vessel strikes may be significant factors limiting recovery.  We telemetered 126 Atlantic sturgeon from 4 different areas with long life acoustic transmitters to determine coastal movements and identify potential impacts; 3 were telemetered 2006 and 2007 in the Delaware Bay; 19 from 2007 to 2010 in the Long Island Sound; 14 from 2009 and 2010 off the coast of North Carolina on the NCCTC; and 90 off the coast of Delaware in 2009 and 2010.  Telemetered Atlantic sturgeon arrived off the Delaware-Maryland coast during the spring (median date May 6, range April 2 to June 23) when water temperatures reached 7°C, and slowly made their way northward with a portion of the population exiting the array by early summer before water temperatures rose above 22.5°C (median date May 25, range April 6 to June 29).  In the fall Atlantic sturgeon exhibited more directed southerly movements transiting the array in as little as two days with only a few taking up to a month in November and early December.  The last telemetered Atlantic sturgeon were detected in the array on December 1 and 3 in 2009 and 2010 respectively when water temperatures fell below 13.1°C and 12.3°C.  In the spring 85% of the Atlantic sturgeon that were detected were located at receiver locations in state waters (<5 km offshore), while in the fall they were detected further offshore with only 41% detected within state waters.  In addition, telemetered Atlantic sturgeon were detected as far south as Gray’s Reef, Georgia in March and as far north as Cabot Strait, Newfoundland during June and August.  Telemetered Atlantic sturgeon over wintered off the coast of the Carolinas and migrated north reaching their summer destinations by July, then returning south in the early fall.  The incorporation of this spatiotemporal data into management strategies could greatly decrease harmful anthropogenic interactions with Atlantic sturgeon and in turn allow for the recovery of this imperiled species.