Secor et al.; Dispersal and growth of Acipenser oxynnchus 



801 



400 -^ 



300 



£ 200 



0) 



100 - 



\\m^\ 



VA 



MD 



n I H#H4i4lwffl Hfl#efl^-Hfmta 



'I I"" I ' I ip+l-H^IIIIII 



1880 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 



Year 



Figure 1 



Atlantic sturgeon landings in Chesapeake Bay. Data from Murawski and Pacheco (1977) and CoUigan et al. (1998). VA = Virginia; 

 MD = Maryland. 



During their first year of life, Atlantic sturgeon remain 

 close to their natal habitats within estuaries (Dovel and 

 Berggren, 1983; Bain, 1997). Following spawning migi-a- 

 tions by adults, benthic eggs are deposited on hard, struc- 

 tured surfaces (e.g. cobble) in regions between the salt front 

 and fall-line of large rivers. Historically, Chesapeake Bay 

 Atlantic sturgeon spawned during April^une (Hildebrand 

 and Schroeder, 1927). Young hatch at ca. 4-6 days after 

 spawning, and following a 7-10 d period swimming upriver, 

 adopt a benthic lifestyle (Smith et al., 1980). Young-of-the- 

 year juveniles initiate seasonal migrations within estuaries 

 (Dovel and Berggren, 1983). Emigration from natal estuar- 

 ies to primarily marine habitats occurs at ages 1 to 5 years, 

 after which subadults wander among coastal and estuarine 

 habitats until maturation, undergoing rapid gi'owth rates 

 (Dovel and Berggren, 1983; Stevenson and Secor, 2000). 



Lack of strong evidence of natural recovery has lead 

 state, federal, academic, and nonprofit organizations to 

 consider an aquaculture-based restoration program for 

 Atlantic sturgeon in the Chesapeake Bay. To examine 

 the feasibility of such a program, 3275 hatchery-produced 

 yearlings (Hudson River progeny produced from a single 

 female and four males) were released into the Nanticoke 

 River (Chesapeake Bay) and their subsequent dispersal 

 and growth was monitored over a one-year period. Spe- 



cifically, we 1) characterized the dispersive behavior of 

 non-native (hatchery-produced) Atlantic sturgeon year- 

 lings through biotelemetry and the capture of sturgeons 

 by fishermen, 2) explored potential relationships between 

 the obsei-ved distribution and abiotic environmental fac- 

 tors, and 3) compared growth rate and diet of released 

 juveniles obsei^ved in our study to those reported in the 

 literature for naturally produced sturgeon. 



Methods 



Juvenile Atlantic sturgeon were obtained from the U.S. Fish 

 and Wildlife Service (USFWS), Northeast Fishery Center, 

 Lamar, Pennsylvania. During June 199.5, Center personnel 

 collected a large female (2.4 m total length) and three male 

 Atlantic sturgeons from the Hudson River near Hyde Park 

 (river km [rkml 135). Fish were transported to the Center 

 for artificial spawning and lan'al rearing. Lai-vae and early 

 juveniles were reared in fresh water at 17°C and fedArtemia 

 nauplii until 30 days after hatching. Juveniles (0.7-2.0 mm 

 diameter) were then fed Biokyowa® fry feed ad libitum 

 during their first year of life. A failure of the water heating 

 system at the Center resulted in loss of temperature con- 

 trol, and juveniles >45 days after hatching, were subjected 



