Ross: Relative value of different estuarine nursery areas for juvenile marine fisfies in North Carolina 



399 



stein and Walters (1981) and O'Neil and Weinstein (1987) 

 reported no consistent differences in spot growth rates be- 

 tween oligohaline and polyhaline creeks in the Cape Fear 

 River and York River, VA, estuaries, respectively. Miller et 

 al. (1985) indicated that spot and Atlantic croaker growth 

 rates were probably not different between Pamlico Sound 

 mesohaline and polyhaline areas. Similarly, Beckman and 

 Dean (1984) found no significant differences in spot growth 

 rates among localities in a small, polyhaline South Caro- 

 lina estuary. Necaise (2000) failed to find growth differ- 

 ences among juvenile summer flounder caged (and fed ad 

 libitum) over a wide range of abiotic habitats in southern 

 North Carolina. Guindon and Miller (1995), however, did 

 find growth rate differences among caged (not fed) south- 

 ern flounder across abiotically similar oligohaline habi- 

 tats in the Pamlico River. Differences in fish growth rates 

 among estuarine habitats (e.g. Sogard, 1992) indicate that 

 there are different species-specific responses to habitats, 

 responses related to zoogeography, or responses related to 



habitat structure or food availability. My data and most of 

 the above studies, covering different years and a variety of 

 estuaries, suggest that variation in growth rates, especially 

 for spot, between PNAs is generally lacking or at least dif- 

 ficult to detect. Such results are consistent with the view 

 that these fishes are hardy, omnivorous, opportunistic 

 colonizers of an undersaturated environment. 



Increasing evidence suggests that oligohaline or fresh- 

 water habitats in the southeastern United States are im- 

 portant nurseries for the OWS juvenile fishes (Rogers et 

 al, 1984; Rozas and Hackney, 1984;Moser and Gerry, 1989; 

 Moser and Hettler, 1989; Peterson and Ross, 1991). In fact, 

 they may be the most valuable habitats, particularly for 

 maximizing survival of some species. The nursery creeks 

 I sampled supported similar growth rates for two species; 

 however, fitness may be most improved upriver, where both 

 growth (in weight) and survival are optimized. Anderson 

 (1988) predicted that juvenile temperate fishes gener- 

 ally choose to maximize growth over reducing mortality. 



