Abstract. — The reproductive bi- 

 ology of Atlantic croaker, Micropo- 

 gonias undulatus, collected during 

 1990-91 from commercial catches 

 in Chesapeake Bay and in Virginia 

 and North Carolina coastal waters 

 (n=3,091), was studied by using 

 macroscopic and microscopic gonad 

 staging, the gonadosomatic index, 

 oocyte diameter distributions, and 

 histological analysis. Atlantic 

 croaker are multiple spawners with 

 asynchronous oocyte development 

 and indeterminate fecundity. Mean 

 length at first maturity for males 

 and females was 182 and 173 mm 

 TL, respectively. More than 85% of 

 both sexes were mature by the end 

 of their first year and all were ma- 

 ture by age 2. Spawning extends 

 over a protracted period (July-De- 

 cember), but individual fish appar- 

 ently spawn over a shorter inter- 

 val. Eleven gravid and running- 

 ripe females were collected within 

 the Chesapeake Bay suggesting 

 some spawning occurs in estuarine 

 waters. Monthly sex ratios indi- 

 cated a strong predominance of fe- 

 males during the main period of 

 spawning. A high incidence of 

 atretic, advanced yolked oocytes in 

 spawning females collected through- 

 out the spawning season suggests 

 that a surplus production of yolked 

 oocytes may be part of the repro- 

 ductive strategy of Atlantic croaker. 



Maturity, spawning, and ovarian 

 cycle of Atlantic croaker, 

 Micropogonias undulatus, in the 

 Chesapeake Bay and adjacent 

 coastal waters* 



Luiz R. Barbieri** 

 Mark E. Chittenden Jr. 

 Susan K. Lowerre-Barbieri** 



Virginia Institute of Marine Science. College of William and Mary 

 Gloucester Point, Virginia 23062 



The Atlantic croaker, Micropogonias 

 undulatus (Linnaeus), ranges from 

 Cape Cod, Massachusetts, to the 

 Bay of Campeche, Mexico (Welsh 

 and Breder, 1923; Johnson, 1978). 

 Although not common north of New 

 Jersey (Hildebrand and Schroeder, 

 1928; McHugh, 1981), it is one of the 

 most abundant inshore, demersal 

 species of the Atlantic and Gulf of 

 Mexico coasts of the United States 

 (Joseph, 1972). 



Despite the large number of stud- 

 ies describing spawning periodicity 

 of Atlantic croaker in the mid-At- 

 lantic and Chesapeake regions (e.g. 

 Hildebrand and Schroeder, 1928; 

 Wallace, 1940; Johnson, 1978; Colton 

 et al., 1979; Morse, 1980; Norcross 

 and Austin, 1988), studies on repro- 

 ductive biology are rare and mostly 

 incomplete. Information on sexual 

 maturity, fecundity, and sex ratios 

 has been reported (Hildebrand and 

 Schroeder, 1928; Wallace, 1940; 

 Morse, 1980). However, speculation 

 on whether or not Atlantic croaker 

 spawn within Chesapeake Bay 

 (Welsh and Breder, 1923; Pearson, 

 1941; Haven, 1957) has not been 

 investigated; estimates of size at 

 maturity (Wallace, 1940; Morse, 



1980) do not agree; estimates of age 

 at maturity (Welsh and Breder, 

 1923; Wallace, 1940) were based on 

 length frequency and scale ageing, 

 which have been shown to be less 

 accurate than otolith ageing for At- 

 lantic croaker (Joseph, 1972; 

 Barbieri et al., 1994); and available 

 fecundity estimates (Morse, 1980) 

 cannot be used without an evalua- 

 tion of Atlantic croaker's fecundity 

 pattern, i.e. whether they have de- 

 terminate or indeterminate annual 

 fecundity. 



Traditionally, estimates of fish 

 fecundity have been based on the 

 assumption that the total number 

 of eggs spawned by a female each 

 year (annual fecundity) is fixed 

 prior to the onset of spawning, a 

 condition known as determinate fe- 

 cundity (Hunter et al., 1992). How- 

 ever, recent evidence (Hunter and 

 Goldberg, 1980; Hunter and Mace- 

 wicz, 1985a; Hunter et al., 1985; 

 Horwood and Greer Walker, 1990) 

 indicates that in many temperate 

 and tropical fish annual fecundity 

 cannot be estimated from the stand- 

 ing stock of advanced oocytes be- 

 cause unyolked oocytes continue to 

 be matured and spawned through- 



Manuscript accepted 9 May 1994. 

 Fishery Bulletin 92:671-685 (1994). 



'Contribution No. 1871 from The College of William and Mary, School of Marine Science, 

 Virginia Institute of Marine Science, Gloucester Point, Virginia 23062. 

 "Present address: University of Georgia Marine Institute, Sapelo Island, Georgia 31327. 



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