Ross: Relative value of different estuanne nursery areas for luvenile marine fishes in Nortfi Carolina 



389 



o 



PAMLICO SOUND 

 upper 



CAPE FEAR 



upper 



Figure 3 



Mean catch per unit of effort for spot in general areas of the Cape Fear and 

 PamHco Sound, NC, estuaries by sampling week, March^une 1987. Vertical 

 bars represent plus and minus one standard error of the mean. The -V-axis 

 abbreviations (from left to right) stand for March, April, April, April, May. 

 May, June. 



significantly (P<0.0.5) warmer than those of the lower 

 Pamlico. The cooler temperatures in the lower Pamlico 

 may have resulted from sampling there at earlier times of 

 the day or on different days of the sampling week. 



Salinity was more variable than temperature, particu- 

 larly within the mesohaline and polyhaline areas (Fig. 2). 

 Within both the Pamlico and Cape Fear systems all areas 

 exhibited significantly different «-test, P<0.05) bottom 

 salinities from each other. As expected, the Cape Fear 

 estuary, with its larger, more channeled river flow and 

 obvious tidal effects, was a more variable system than the 

 Pamlico system. During this study mean salinities within 

 the lower and middle areas of the Cape Fear system varied 

 over a range of 11.8%f and 14.2%f, respectively, whereas 

 mean salinities in all other areas (including the Pamlico) 

 varied over a range less than 9%f . The lower Cape Fear 

 creeks had significantly higher (P<0.05) salinities than 

 those of the lower Pamlico; however, the middle and upper 

 Pamlico areas had significantly higher (P<0.05) salinities 

 than their counterparts in the Cape Fear, even though the 

 upper Pamlico area was twice as far from an inlet as the 

 upper Cape Fear. Salinities declined rapidly in the Cape 



Fear with increasing distance from the inlet; however, this 

 relationship was more variable in the Pamlico System 

 (Fig. 2). In both systems, overall mean salinity (S) was ac- 

 curately predicted by distance (D, in km) from the inlet: 

 Cape Fear: S=23.5 - 0.55(D), r2=0.95, n=10 and Pamlico: 

 S=20.4 - 0.17(D), r-=0.92, n = l8. 



Leiostomus xanthurus 



Distribution Spot was the more widely distributed of the 

 two species (Figs. 3-5). At the earliest sample date, small 

 numbers of spot had accumulated in all areas of the Pam- 

 lico system (Fig. 3). Peak abundance was observed in the 

 lower and mid-lower areas by the second sample date and 

 in the middle and upper areas by the third sample date. 

 Although more spot were collected in the lower Pamlico, 

 numerical differences between areas were not extreme 

 (Figs. 3 and 4). Overall, the least numbers of spot occurred 

 in the middle region (Figs. 3 and 4). 



In the Cape Fear system, overall spot abundance was 

 similar between the upper and lower regions, and, as in the 

 Pamlico, the least numbers were collected from the middle 



