AGE, GROWTH, AND DISTRIBUTION OF LARVAL SPOT, 

 LEIOSTOMUS XANTHURUS, OFF NORTH CAROLINA 



Stanley M. Warlen and Alexander J. Chester^ 



ABSTRACT 



Age and growth of the early life history stages of spot, Leiostomus xanthurus, were determined from 

 daily growth increments on otoliths of larval and early juvenile spot collected from Beaufort Inlet, NC, 

 to the continental shelf break during the fall and winter of 1978-79 and 1979-80. Spawning occurred on 

 the mid to outer continental shelf between early November and early March, but appeared to be concen- 

 trated from mid-December through January. Generally, the youngest larvae were found further offshore; 

 ages and lengths increased closer to shore Larvae entered the estuary at an average age of 59 days (range 

 40-74 days) and an average size of 13.6 mm (range 11.3-15.6 mm). Significantly younger and smaller lar- 

 vae immigrated at the beginning and end of the immigration period. Fish entered the estuary segregated 

 by age as indicated by the small within-sample variation in age A Gompertz growth equation was used 

 to express the relationship between age and standard length for 69 larvae collected in 1978-79 and 557 

 collected in 1979-80. Spot grew from about 1.6 mm SL at hatching to 17-19 mm SL at 90 days. There 

 were no significant differences in growth parameters between years; age-specific growth rates declined 

 from =5%/day at age 10 days to <l%/day at age 90 days. 



The larvae of a number of commercially important 

 fishes that spawn on the outer continental shelf of 

 the southeastern United States are transported 

 shoreward to estuaries where development is com- 

 pleted (McHugh 1966; Chao and Musick 1977; Wein- 

 stein and Walters 1981; Warlen 1982). Although this 

 general pattern of oceanic spawning and estuarine 

 development has been known at least since publica- 

 tion of the work of Hildebrand and Cable (1930), 

 most recent studies have considered only the 

 estuarine phase (Chao and Musick 1977; Weinstein 

 and Walters 1981), and virtually no quantitative data 

 exist on age and size distribution or growth of lar- 

 vae between the time of spawning and estuarine 

 immigration. 



Spot, Leiostomus xanthurus, spawn offshore and 

 are widely distributed in coastal waters from the 

 mid-Atlantic to Tfexas. Larvae have been reported 

 from North Carolina to Massachusetts (Berrien et 

 al. 1978), from the South Atlantic Bight (Fahay 1975; 

 Powles and Stender 1976), and from the Gulf of Mex- 

 ico (Fruge 1977; Govoni et al. 1983). Despite studies 

 on egg and larval development (Fruge and Truesdale 

 1978; Powell and Gordy 1980), growth of juveniles 

 (Weinstein and Walters 1981), and feeding ecology 



'Southeast Fisheries Center Beaufort Laboratory, National 

 Marine Fisheries Service, NOAA, Beaufort, NC 28516-9722. 



Manuscript accepted January 1985. 

 FISHERY BULLETIN: VOL. 83, NO. 4, 1985 



of larvae (Govoni et al. 1983) and juveniles (Chao and 

 Musick 1977), little is known of the early growth 

 history of spot. Our objectives were to 1) determine 

 the estimated age and size distribution of young spot 

 from the time of hatching in the ocean to recruit- 

 ment into the estuary, 2) estimate larval growth 

 rates, 3) estimate spawning times, and 4) determine 

 when young spot enter the estuary. 



METHODS 



Sources of Data 



Larvae were collected off Beaufort, NC, during 11 

 2-d cruises of the RV John de Wolf II, from December 

 1978 to April 1979 (grid design, stations 1-10) and 

 from November 1979 to March 1980 (transect 

 design, stations 11-19) (Fig. 1). At all stations, ex- 

 cept Beaufort Inlet, samples were obtained from 

 oblique plankton hauls (Powles and Stender 1976) 

 collected with 60 cm diameter bongo nets (mesh sizes 

 333 or 505 /^m) rigged with flow meters. A surface 

 tow was made at Beaufort Inlet. Larvae were also 

 collected with a neuston net (Hettler 1979) about 1 

 mi inside the mouth of the Newport River at Pivers 

 Island (Fig. 1) seven times from mid-December 1979 

 to mid-April 1980. Samples were preserved in 95% 

 ethanol (final concentration =75%) within 5 min of 

 collection. 



587 



