800 



Abstract— Significant fisheries for Ches- 

 apeake Bay Atlantic sturgeon,Acipenser 

 oxyrinchus, have been absent for nearly 

 a century, and there has been no evi- 

 dence of recovery in the intervening 

 years. Endangerment of Atlantic stur- 

 geon in the Chesapeake Bay has stim- 

 ulated interest in aquaculture-based 

 restoration programs. A critical and 

 unknown issue is whether hatchery 

 released fish would encounter habitats 

 that support growth and survival. In 

 July 1996, approximately three thou- 

 sand Atlantic sturgeon yearlings were 

 released into Nanticoke River (Mary- 

 land) and subsequently tracked to 

 evaluate their growth and dispersal. 

 Biotelemetry of 32 individuals showed 

 down-estuary emigration into the Che- 

 sapeake mainstem habitat during sum- 

 mer and fall at average ground speeds 

 below 0.5 km/d. During the first year 

 after release, 262 yearlings were cap- 

 tured by commercial fishermen. All 

 yearlings and two-year-old fish were 

 determined to be of hatchery origin (8% 

 capture rate). Yearlings were captured 

 throughout the Chesapeake Bay main- 

 stem and tributaries. Two released stur- 

 geon were captured in the Albemarle 

 Sound System (Chowan River. NC). 

 Juveniles captured during summer 

 and fall experienced ca. 1.5% daily 

 specific growth rate. Diets comprised 

 annelid worms, isopods, amphipods, 

 and mysids. Wide dispersal, high inci- 

 dence of feeding, and positive growth 

 rates suggested that hatchery-produced 

 juveniles dispersed to areas that sup- 

 ported consumption, growth, and sur- 

 vival. Because the Chesapeake Bay 

 continues to support juvenile habitats, 

 we propose that curtailed or absent 

 spawning stock or spawning habitat, 

 or both, are principal factors that have 

 contributed to lack of Atlantic sturgeon 

 recovery during the twentieth century. 



Dispersal and growth of yearling 

 Atlantic sturgeon, Acipenser oxyrinchus, 

 released into Chesapeake Bay* 



David H. Secor 



Edwin J. Niklitschek 



Jill T. Stevenson 



Troy E. Gunderson 



Chesapeake Biological Laboratory 



University of Maryland Center of Environmental Science 



1 Williams Street 



Solomons, Maryland 20688 



Steven P. Minkkinen 



Brian Richardson 



Benjamin Florence 



Fisheries Division 



Maryland Department of Natural Resources 



580 Taylor Avenue B-2 



Annapolis, Maryland 21401 



Michael Mangold 



Jorgen Skjeveland 



us. Fish and Wildlife Service, MFRO 

 177 Admiral Cochrane Dnve 

 Annapolis. Maryland 21401 



Anne Henderson-Arzapalo 



U.S. Geological Survey 



Leetown Science Center 



1700 Leetown Road, Kearneysville, West Virginia 25430 



Manuscript accepted 1 June 2000. 

 Fish. Bull. 98:800-810 (2000). 



In Chesapeake Bay, Atlantic sturgeon, 

 Acipenser oxyrinchus, may be func- 

 tionally extirpated (Secor'; Speir and 

 O'ConnelP). Although sporadic obser- 

 vations of yearlings and adults have 

 been reported over the last two decades 

 (Colligan et al., 1998), the probability 

 of population extirpation based upon 

 the infrequency of these observations, 

 is high (Grogan and Boreman, 1998). 

 Depletion of Atlantic sturgeon in the 

 Chesapeake Bay followed a period of 

 high exploitation in the late 19th cen- 

 tury (Fig. 1), during which overfishing 

 occurred for most Atlantic sturgeon 

 populations (Murawski and Pacheco, 

 1977; Secor and Waidman, 1999). Also, 

 sedimentation and eutrophication have 

 dramatically affected the Chesapeake 

 Bay's environment during the past cen- 



tury (Officer et al., 1984; Cooper and 

 Brush. 1991), resulting in loss and deg- 

 radation of spawning and nursery hab- 

 itats that may have contributed to loss 

 in viability of sturgeon populations. 



Contribution 3335 of the University of Mary- 

 land Center for Environmental Science, 

 Chesapeake Biological Laboratory, 1 Wil- 

 liams StreetSolomons, Maryland 20688. 

 Secor D.H. 1995. Chesapeake Bay Atlan- 

 tic sturgeon: current status and future 

 recovery. Unpubl. manuscript. Chesa- 

 peake Biological Laboratory. P.O. Box 38, 

 Solomons, MD 20688-0038, 10 p. 

  Speir. H., and T.O'Connell. 1996. Status 

 of Atlantic sturgeon in Maryland's Ches- 

 apeake Bay. LInpubl. Manuscript. MD 

 Dep Natural Rrsources.Tawes State Office 

 Building, 580 Taylor Avenue, Annapolis, 

 MD 21401, 7 p. 



