Abstract.— Larval spot Leiosto- 

 mus xanthurus were sampled weekly 

 as they recruited to the Newport 

 River estuary near Beaufort Inlet, 

 North Carolina to determine their 

 density, and age and size composi- 

 tion. Density data and otolith age 

 distributions were used to calculate 

 the relative contribution of birth- 

 week cohorts to the seasonal recruit- 

 ment of spot larvae. The protracted 

 1987-88 spawning season extended 

 from mid-October to mid-March, 

 with 90% in a 2-month period be- 

 ginning mid-November. Larvae were 

 recruited to the estuary over 5 

 months at a mean age of 82 d and 

 mean standard length of 17.2 mm. 

 Smaller, younger larvae generally 

 immigrated to the estuary early ( De- 

 cember-January ) and late (late 

 April), while larger, older larvae im- 

 migrated during the interim peak re- 

 cruitment period (February to mid- 

 April). In any recruitment week, 

 larvae were from 2-10 birthweek co- 

 horts, but recruitment was strongly 

 influenced by the number of larvae 

 of the dominant cohorts. 



Larval spot were also sampled in 

 the ocean between Cape Fear and 

 Oregon Inlet off North Carolina to 

 determine their distribution, abun- 

 dance, and size and age composition. 

 Age and size of larvae were inversely 

 related to distance from shore. High- 

 est densities of larvae were gener- 

 ally found outside the 30 m isobath. 

 Distribution data supported the hy- 

 pothesis that spot spawned south of 

 Cape Hatteras on the outer con- 

 tinental shelf contribute to re- 

 cruitment in Chesapeake Bay. A 

 Kolmogorov-Smirnov test did not 

 demonstrate a significant difference 

 between birthdate distributions for 

 ocean and estuarine larvae. This im- 

 plied that mortality was not age- 

 specific for larvae collected at differ- 

 ent times. A Laird-Gompertz growth 

 equation fit to age and size data for 

 larvae collected in the ocean and es- 

 tuary predicted that they grew from 

 1.2 mm at hatching to 16.1mm in 

 80 d. 



Spawning time, growth, and 

 recruitment of larval spot 

 Leiostomus xanthurus into a 

 North Carolina estuary 



Cesar Flores-Coto 



Instituto de Ciencias del Mar y Umnologia 

 Universidad Nacional Autonoma de Mexico 

 Mexico 04510 D.F 



Stanley M. Warlen 



Beaufort Laboratory, Southeast Fisheries Science Center 

 National Marine Fisheries Service. NOAA 

 Beaufort, North Carolina 28516-9722 



Manuscript accepted 28 October 1992. 

 Fishery Bulletin, U.S. 91:8-22 ( 1993). 



Spot Leiostomus xanthurus is distrib- 

 uted from the Gulf of Maine to the 

 Bay of Campeche, Mexico. The area 

 of greatest abundance and the cen- 

 ter of the commercial fishery on the 

 Atlantic Coast extends from Chesa- 

 peake Bay to South Carolina (John- 

 son 1978, Mercer 1989). Spot spawn 

 offshore during the fall and winter, 

 and their larvae immigrate to nurs- 

 ery areas in estuaries (Hildebrand & 

 Cable 1930, Fahay 1975, Chao & 

 Musick 1977, Warlen & Chester 

 1985). Historically, spot have been 

 among the most important commer- 

 cial and recreational fishes in North 

 Carolina (Miller et al. 1984, Mercer 

 1989). Hettler & Chester (1990), 

 Warlen & Burke (1990), and Warlen 

 (unpubl. data) have shown that lar- 

 val spot are consistently the most 

 abundant of the fall/winter spawn- 

 ing species whose larvae are found 

 in Beaufort Inlet, North Carolina. 

 The abundance of this species is prob- 

 ably a function of the relatively high 

 densities of larvae that recruit into 

 estuaries over an extended period of 

 several months. Recruitment is de- 

 fined as the movement (immigration) 

 of spot larvae from the ocean into 

 the lower estuary. 



There have been studies on the 

 early life history of spot regarding 



development (Fruge 1977, Fruge & 

 Truesdale 1978, Powell & Gordy 

 1980), feeding (Govoni et al. 1983, 

 1985), distribution and abundance 

 (Lewis & Judy 1983, Warlen & 

 Chester 1985, Sogard et al. 1987), 

 metabolic responses to cold (Hoss et 

 al. 1988), and age and growth 

 (Beckman & Dean 1984, Warlen & 

 Chester 1985, Siegfried & Weinstein 

 1989). Although Beckman & Dean 

 (1984) determined the relationship 

 between spawning and part of the 

 estuarine recruitment period, no 

 studies have estimated the relative 

 contribution of age (birthweek) co- 

 horts to the number of estuarine re- 

 cruits, or the seasonal changes in 

 relative abundance of larvae that sur- 

 vive to reach the estuary. Such stud- 

 ies require systematic, quantitative 

 sampling of larvae newly recruited 

 to the estuary in order to estimate 

 within-season relative abundances. 

 Also, they require age determination 

 of larvae throughout recruitment. 



The density of larvae recruited 

 from each birthweek gives an esti- 

 mate of the spawning-date distribu- 

 tion of spot which can be compared 

 with similar distributions determined 

 from either offshore egg production 

 (although these are difficult to ob- 

 tain) or younger larvae caught off- 



