Abstract.- Spring ichthyoplank- 

 ton surveys in the tidal freshwater 

 reaches of Virginia rivers were used 

 to document the temporal and spatial 

 occurrence of spawning by striped 

 bass Morone saxatilis (Walbaum). 

 Single river systems were intensive- 

 ly surveyed in 1980 (York River sys- 

 tem), 1981 (James River system), 

 and 1982 (Rappahannock River). In 

 spring 1983, all three river systems 

 were sampled at approximately 

 weekly intervals. Some spawning oc- 

 curred in all years, including those 

 yielding poor year-classes (1980 and 

 1981). Spawning occurred largely 

 within the first 40 km of tidal fresh- 

 water in major rivers, except when 

 drought conditions displaced spawn- 

 ing upstream in advance of encroach- 

 ing saltwater. Eggs appeared in 

 sharp, brief peaks of abundance, 

 usually between the third week in 

 April and the first week in May. 

 Peak densities coincided with rapid- 

 ly rising water temperatures in the 

 range 13.7-19.5°C. 



Distribution of Striped Bass 

 Morone saxatilis (Walbaum) 

 Eggs and Larvae in Major 

 Virginia Rivers* 



George C. Grant 

 John E. Olney 



Virginia Institute of Marine Science, School of Marine Science 

 College of William and Mary, Gloucester Point, Virginia 23062 



The importance of Chesapeake Bay 

 spawning grounds to Atlantic coast 

 stocks of striped bass Morone saxa- 

 tilis (Walbaum) has long been recog- 

 nized (Merriman 1941; Raney 1952; 

 Briggs 1962; Alperin 1966; Schaefer 

 1967, 1968, 1972; Berggren and 

 Lieberman 1978; Kohlenstein 1981; 

 Fabrizio 1987a, 1987b). Striped bass 

 spawning in Chesapeake Bay and 

 its tributaries has been documented 

 from collections of eggs and larvae 

 (Tresselt 1952, Rinaldo 1971, John- 

 son and Koo 1975, Polgar et al. 1976, 

 Conte et al. 1979, Kernehan et al. 

 1981, Setzler-Hamilton et al. 1981), 

 and survey data on the distribution 

 of juveniles or presence of ripe adults 

 (Vladykov and Wallace 1952, Grant 

 and Joseph 1969, Markle and Grant 

 1970, Grant 1974). 



Direct documentation of striped 

 bass spawning in Virginia rivers 

 based on plankton collections of eggs 

 and larvae was provided by consecu- 

 tive single surveys of five rivers in 

 April and May 1950 (Tresselt 1952); 

 a single river survey during the en- 

 tire 1966 spawning season (Rinaldo 

 1971); and a single river survey dur- 

 ing the entire 1985 spawning season 

 (McGovern and Olney 1988). This 

 paper documents temporal and spa- 

 tial occurrence of striped bass eggs 

 and larvae in Virginia's major river 



Manuscript accepted 19 October 1990. 

 Fishery Bulletin, U.S. 89:187-193 (1991). 



* Contribution no. 1626 of the Virginia Insti- 

 tute of Marine Science and School of Marine 

 Science, College of William and Mary. 



systems. The York, James, and Rap- 

 pahannock river systems, respec- 

 tively, were surveyed in the years 

 1980-82; all three rivers were sam- 

 pled in 1983. 



Methods and materials 



Lower tidal freshwater portions of 

 the James, Chickahominy, Pamun- 

 key, Mattaponi, and Rappahannock 

 Rivers were divided into 3-mile 

 (5-km) strata, from which single sta- 

 tions were randomly selected prior to 

 each sampling trip. Number of strata 

 (in parentheses) and cruise dates 

 were: the Pamunkey River (10), 16 

 April- 13 June 1980 and 5 April- 11 

 May 1983; Mattaponi River (6), 18 

 April-14 June 1980; James River 

 (10), 22 April-19 June 1981 and 8 

 April-8 May 1983; Chickahominy 

 River (7), 21 April-18 June 1981; and 

 Rappahannock River (9), 5 April-6 

 June 1982 and 9 April-13 May 1983. 

 Stations were sampled semi-week- 

 ly to weekly within strata extending 

 upstream from the limits of brackish 

 water (~0.5"A») to beyond the ob- 

 served occurrence of striped bass 

 eggs. Collections at each station were 

 stepped-oblique, daylight tows of a 

 60-cm bongo sampler, equipped with 

 333-^m mesh nets and flowmeters. 

 Length of tows were 2-6 minutes; 

 tows in deep water were of longer 

 duration and tows encountering ex- 

 cessive detritus loads were short- 

 ened. Catches from the paired nets 



187 



