632 



Spawning of American shad (Alosa sapidissimd) 

 and striped bass (Morone saxatilis) in the 

 Mattaponi and Pamunkey Rivers, Virginia* 



Donna Marie Bilkovic 



John E. OIney 



Carl H. Hershner 



Virginia Institute of Manne Science 

 College of William and Mary 

 Rt 1208 Create Road 

 Gloucester Point, Virginia 23062 

 Email (for D M Bilkovid: donnabeivimsedu 



In the Atlantic coastal region, Ameri- 

 can shad (Alosa sapidissima ) is highly 

 prized for its flesh and roe. Spawning 

 runs have been heavily fished and 

 since the late 1800s, landings have 

 shown steady declines to the extent 

 that Maryland declared a fishing 

 moratorium in 1980, and Virginia fol- 

 lowed in 1994 for Chesapeake Bay and 

 its tributaries (ASMFC, 1999). Shad 

 restoration projects are underway to 

 restock depleted spawning runs, espe- 

 cially in regions where stream impedi- 

 ments have been or are being removed. 

 Coastal ocean intercept gill-net fisher- 

 ies have remained in place despite 

 criticism and speculation about their 

 impact on populations, particularly 

 those river systems stocks that are 

 depleted. The Atlantic States Marine 

 Fisheries Commission Shad Board 

 (ASMFC, 1999) adopted a fishery man- 

 agement plan for American shad and 

 river herring that included a five-year 

 phase-out of the ocean fishery and that 

 required states to develop an approved 

 fishing or recovery plan for each stock 

 under restoration. In Virginia, this 

 requirement applies to the James and 

 York rivers. 



Although the roe fishery for Ameri- 

 can shad has historically been impor- 

 tant, there is little information about 

 the specific spawning locations of 

 these broadcast spawners. American 

 shad are anadromous fish native to the 

 Atlantic coast of North America, with 

 a range extending from southeastern 

 Labrador to the St. Johns River, Flor- 

 ida. In Chesapeake Bay tributaries, 



American shad deposit semidemersal 

 eggs in the freshwater portions of the 

 estuaries in the spring, usually begin- 

 ning in March and ending by early 

 June with peaks in April (Klauda et 

 al, 1991). American shad have histori- 

 cally ascended farther upriver than 

 at present, within tributaries where 

 obstructions to movements upstream 

 now exist. Prior to dam building in the 

 1800s on the James River, large num- 

 bers of American shad traveled over 

 335 miles from Chesapeake Bay into 

 the Jackson and Cowpasture rivers 

 (Mansueti and Kolb, 1953). 



The York River, a coastal plain trib- 

 utary located in the Chesapeake Bay 

 watershed, is formed by the conflu- 

 ence of the Pamunkey and Mattaponi 

 Rivers at West Point (Fig 1). The 

 Pamunkey River has a larger water- 

 shed (3768 km'-) and average spring 

 discharge rate (47.5 m%) than the 

 Mattaponi River (2274 km'^; 27.2 m^/s, 

 respectively). Watershed sizes are 

 based on U.S, Geological Survey digital 

 line graph data (DLG) at 1:100,000. 

 On these unobstructed rivers, annual 

 releases of hatchery-reared American 

 shad approximate two to four million 

 fry through efforts of the Virginia Game 

 and Inland Fisheries (VGIF) and an es- 

 timated 2.5 to 3 million fry are released 

 by the Pamunkey tribal government. In 

 addition there are unknown contribu- 

 tions from the Mattaponi tribal govern- 

 ment (Gunther'). Current monitoring 

 of adult catches indicates that the York 

 River supports the strongest runs of 

 shad in Virginia (Olney and Hoenig^). 



American shad in the York River are 

 used as the source stock for hatchery ef- 

 forts in the James and Potomac rivers. 

 Thus, the restoration efforts in Virginia 

 are dependent on the productivity of 

 the York River. 



Within the freshwater tidal portions 

 of the Mattaponi and Pamunkey riv- 

 ers, numerous other species spawn, 

 including striped bass (Morone saxati- 

 lis) (McGovern and Olney, 1988; Grant 

 and Olney, 1991). The Chesapeake 

 Bay stock has rebounded after severe 

 declines in the 1970s and early 1980s 

 as a result of successful management 

 and several years of successful re- 

 production (Olney et al, 1991; Field, 

 1997). The extent of the spawning area 

 for both American shad and striped 

 bass is in part a function of salinity 

 and temperature. Striped bass spawn 

 from the limit of brackish water to 

 freshwater in the rivers of Chesa- 

 peake Bay from early April through 

 the end of May (Setzler-Hamilton et 

 al., 1981), and American shad spawn 

 in freshwater (Leim, 1924). McGov- 

 ern and Olney (1996) noted that the 

 lower limit of striped bass spawning 

 followed the 1 ppt salinity contour, and 

 Secor and Houde (1995) postulated 

 that the freshwater-saltwater inter- 

 face may act as a down-river barrier to 

 striped bass egg and larval advection. 

 Based on suitable temperature ranges 

 (12-24°C for striped bass [Setzler- 

 Hamilton et al, 1980; Rutherford and 

 Houde, 1995] and 12-25°C for Ameri- 



* Contribution 2449 of the Virginia Insti- 

 tute of Marine Science, College of William 

 and Mary, Gloucester Point, VA '23062. 



' Gunther, T. 2000. Personal commun. 

 Virginia Game and Inland Fisheries, 

 Richmond, Virginia 23230. 



- Olney, J. E., and J. M. Hoenig, 2000. 

 Monitoring relative abundance of Ameri- 

 can shad in Virginia's Rivers. March 

 1998-1999. Final report to the U.S. Fish 

 and Wildlife Service and Virginia Marine 

 Resources Commission, 53 p. Contract 

 number F-116-R-1. Virginia Institute of 

 Marine Science, Gloucester Point, Virginia. 



Manuscript accepted 13 February 2002. 

 Fish. Bull. 100:632-640 (2002). 



