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Fishery Bulletin 92|4). 1994 



out the spawning season. This condition is called 

 indeterminate fecundity (Hunter et al., 1992). The 

 only way to estimate annual fecundity, therefore, is 

 by estimating batch fecundity — the number of eggs 

 released during each spawning — and multiplying it 

 by spawning frequency — the number of times an 

 average female spawns during the spawning season 

 (Hunter and Macewicz, 1985a; Hunter et al., 1985, 

 1992). Although the extended spawning season of 

 Atlantic croaker (Wallace, 1940; Colton 

 et al., 1979; Warlen, 1982) suggests it 

 is a multiple spawner with indetermi- 

 nate fecundity, no attempt has been 

 made to evaluate its fecundity pattern. 

 In this study we test the assumption 

 of determinate annual fecundity and 

 describe spawning periodicity, size and 

 age at maturity, sex ratios, ovarian 

 cycle, and oocyte atresia for Atlantic 

 croaker in the Chesapeake Bay and 

 adjacent coastal waters. 



Methods 



Four approaches were used to sample 

 Atlantic croaker for this study. In 1990 

 and 1991 fish were collected from com- 

 mercial poundnet, haul-seine, and 

 gillnet fisheries that operate from late 

 spring to early fall in the lower Chesa- 

 peake Bay (Fig. 1). Local fish process- 

 ing houses and seafood dealers were 

 contacted weekly during April-October 

 1990 and 1991, and one 22.7 kg (50 lb) 

 box of fish of each available market 

 grade (small, medium, or large) was 

 purchased for processing. Since Atlan- 

 tic croaker migrate out of Chesapeake 

 Bay in midfall to overwinter offshore 

 (Haven, 1959), monthly samples from 

 November to March 1990 and from No- 

 vember through December 1991 were 

 obtained from commercial trawlers op- 

 erating in Virginia and North Carolina 

 shelf waters. In addition to these col- 

 lections, daily samples from a gill net 

 in the lower York River were obtained 

 during the periods August-October 

 1990 and July-October 1991, except on 

 weekends. In 1991 the net was emptied 

 twice a day: in the early morning (6:00- 

 8:00 am) and in the evening (5:00-7:00 

 pm). Time of death was recorded for fish 

 alive at the time the net was emptied. 



Daily gillnet samples were used to monitor small- 

 scale (less than weekly) changes in Atlantic croaker 

 reproductive condition and to collect hydrated or re- 

 cently spawned females. Finally, collections from the 

 commercial fisheries were supplemented by fish ob- 

 tained from the Virginia Institute of Marine Science 

 (VIMS) juvenile bottom trawl survey. The VIMS trawl 

 survey used a monthly stratified random sampling 

 program in the lower Chesapeake Bay and monthly 



Figure 1 



Map of the Chesapeake Bay and mid-Atlantic region. Black dots in 

 Chesapeake Bay indicate poundnet, haul-seine, or gillnet collection 

 sites. Hatched area off Virginia and North Carolina indicates where 

 otter trawl collections of Atlantic croaker, Micropogonias undulatus, 

 were obtained. 



