Ross: Relative value of different estuanne nursery areas for juvenile manne fishes in Nortfi Carolina 



401 



to be the most productive, but their study lacked stations 

 near the inlets and in freshwater areas. Weinstein et al.'s 

 (1980) uppermost Cape Fear stations were the same as 

 my middle area and generally produced lower densities of 

 spot than polyhaline areas, but lacking upriver stations, 

 the meaning of this in the present context is inconclusive. 

 These fishes seem to opt either for rapid settlement in poly- 

 haline environments or delayed settlement in oligohaline 

 areas — mesohaline settlement being less "preferred." 



The conclusion that PNAs were not equally valuable 

 and the observation that spot were not most abundant 

 in the best habitats, indicated that variation in estuarine 

 distribution could control or at least regulate (fine tune) 

 year-class strength. If movement to general regions of 

 the estuary is largely passive (Pietrafesa et al., 1986b; Pi- 

 etrafesa and Janowitz, 1988), then my results predict that 

 year-class strength of these species would be decreased 

 when transport conditions force the majority of the recruits 

 toward middle or lower region PNAs. Alternatively, year 

 class strength would be enhanced by conditions favoring 

 greater upstream transport, assuming carrying capacities 

 of the habitats were not exceeded. Ross (1992) proposed 

 that these systems were recruitment limited, that post- 



settlement mortality was less important in controlling 

 year-class strength than early life history events prior to 

 settlement. If true, factors affecting variation in estuarine 

 distribution may indirectly adjust year-class strength, not 

 control it. Additional data on mortality rate variation in 

 relation to density during the estuarine and oceanic early 

 life history is required to validate this hypothesis. 



Acknowledgments 



I thank John M. Miller, G, T. Barthalmus, L. B. Crowder, 

 and L. J. Pietrafesa for their support during this study. I 

 thank K. H. Pollock for statistical advise. Field sampling 

 required the efforts of many people. The NC Division of 

 Marine Fisheries (Washington and Wilmington offices) 

 played a large role in sampling, and I especially thank 

 Fred Rohde, John Schoolfield, Otto Rutten, Morris Allison, 

 Greg Judy, Lele Tison, and Jess Hawkins of that organiza- 

 tion. B. M. "Mac" Currin was important throughout the 

 study, and I thank him for his contributions in the field, 

 laboratory, and in reviewing manuscripts. John S. Burke 

 also provided help in the field. I thank the Beaufort Labo- 



