Atlantic sturgeon of the Delaware: historical perspectives and current approaches to understanding habitat requirements Dewayne Fox1, Lori Brown1, Phil Simpson1, Kevin Magowan2, and Joseph Hightower2 1 Delaware State University 2 North Carolina Cooperative Fish and Wildlife Research Unit

Acknowledgments Mr. Hal Brundage PA State Wildlife Grant Program NOAA EPP and NMFS Anadromous Fish Conservation Act Funding Larry and “Limbo” Voss USCG Lt. Cmdr. (Ret) Thomas Flynn

Atlantic sturgeon (Acipenser oxyrinchus oxyrinchus) Anadromous Long lived Late-maturing Present status ESA Petition Status of Delaware stock

100 years of Atlantic Sturgeon Management in the Delaware River “The roe was considered worthless except as bait to catch eels, and perch or to feed the hogs” --Cobb, J. N. 1900 Salem, NJ Historical Society

“Under the present conditions it is only a question of a few years until the day of the sturgeon fishery will have collapsed” Tower, W. S. 1908

Delaware River Atlantic Sturgeon Fishery Historic Abundance estimated at 180K Females in 1890 Average weight female 118 kg male 29.5 kg Golden Years Landings (million lbs) Stock Collapse Recruitment Failure Secor and Waldman 1999 Year

Historical Atlantic sturgeon spawning areas Cobb (1899) Borodin (1925) Studies based on commercial fishery Spawning mid-May-June Spatial and temporal separation with shortnose sturgeon

Anthropogenic changes in Atlantic sturgeon habitat Habitat Changes Dredging Historic depths 5.5-7.1 m Post 1940s >12.2 m Saltwater intrusion Increased tidal amplitude Approximate extent of salt intrusion Lowermost hardbottom habitat

Research Questions Identification of spawning sites Migration patterns of juveniles Juvenile habitat characterization

Telemetry Equipment Vemco ltd. VR-16 6H tags 2 year battery life VR-2 passive receivers Combination of passive-active tracking Compatible with other species being tracked shortnose sturgeon (ERC) sandbar shark (DE and VA) sandtiger shark striped bass (MA) Limulus (07) weakfish (UD)

2005 Relocations Atlantic sturgeon transmitter number 1229 July 15 2005 Relocations Atlantic sturgeon transmitter number 1229 July 16 – October 8 June 7 November 22 Upper most point was sort of a random venture on

2006 Relocations Atlantic sturgeon transmitter number 1229 Flood response? May 18 May 18 – June 27 July 7 – Oct 4 June 30 Oct 4 – Oct 31 April 25

2005-2006 Juvenile Sturgeon Passive Relocations Marcus Hook Anchorage Cherry Island Flats Artificial Island C & D Canal Relocations 33 juveniles 48,272 Detections Concentration Areas Shirey 1998 Proposed LNG plant CD Canal useage 4 fish used CD canal 2 moved to Chesapeake

Juvenile Habitat Utilization Use of active tracking for precise location Almost exclusive use of deep/channelized habitats Localized movements during summer months

Atlantic sturgeon Captured June 1 Ripe Male June 1 – October 27

Biotelemetry Array Combined approach is a powerful tool Broad scale patterns Fine scale habitat use Collection issues Sampling rare fish Gear restrictions and traffic considerations Application of new technologies to the habitat problem

Comparing Split-beam & DIDSON Technologies 430kHz Single beam Echoes major scattering organs some hard parts Echoes denotes fish passing through beam. Color indicates target strength Color change in this window shows direction of movement through the beam

Comparing Split-beam & DIDSON Technologies 1.8MHz 96 beams to create HQ image High frame rates Shows movement, body shape, and structure

Atlantic sturgeon Aquaculture ponds – DSU

Atlantic sturgeon Aquaculture ponds – DSU

Split-beam/DIDSON Field Trials December 14-15, 2006 Known overwintering area for Shortnose sturgeon Federally endangered Maximum size ~ 1.2 m

Split-beam Results Non-invasive Targets close to and or on bottom “Fish” target Non-invasive Targets close to and or on bottom Relatively rapid assessment of large areas (1-2 kts)

Shortnose sturgeon Channel – DE River

DIDSON Results Non-invasive Allows sturgeon identification Size estimates Population estimates through application of swept area methods

Thoughts of a Sturgeon Harvester “As I sat alone in my cabin Thinking of days gone by, When sturgeon and shad were plentiful And living was not so high, I saw as in a vision That seemed as clear as day, Men I had known at Bayside, But long since passed away” George Pyle, 1920