holepunch so researchers will know when 

 they encounter the same fish. 



Striped bass, however, have scientific 

 tags inserted. "That's because there are so few 

 in the Neuse. On Monday, they got over 400 

 on the Roanoke. Here, we might get 200 in a 

 season," Waters says. He explains that "the 

 Roanoke has a stronger fishery due to 

 restoration efforts" that included harvest 

 restrictions and regulation of flow rates from 

 Kerr Lake. 



Using electrofishing to capture and tag 

 American shad and striped bass is familiar to 

 Hightower. He also used electrofishing in his 

 post dam-removal study. The difference was 

 that the fish were tagged with ultrasonic 

 transmitters and monitored with telemetry. 



Hightower and coresearcher Stephan 

 Bowman, then a graduate student in zoology, 

 tracked fish actively by boat with multidirec- 

 tional antennas, and passively, with fixed 

 telemetry stations both upstream and 

 downstream of the former dam site. The 

 advantage of his study, Hightower says, is that 

 "you can get more information from an 

 individual fish, but you might only have 10 or 

 20 fish with transmitters at any one time." 



During the study, researchers plotted the 

 locations of spawning activity using global 

 positioning system technology. But as high- 

 tech as the study was, one way to find 

 spawning sites was to sit quietly in a boat in 

 the evenings. 



"Steve listened for splashing," 

 Hightower says, explaining that splashing at 

 the water surface is part of spawning behavior 

 and one of the signs of spring on the river. 

 "It's a real intensive period, then it's over. 

 They're gone," he says. 



Researchers noted differences in 

 behaviors of bass and shad. "Striped bass are 

 more dispersed in the river," he says. "There 

 doesn't seem to be a well-defined spawning 

 area in the Neuse." 



Waters and Farmer move to a new 

 sampling spot at a bend in the river where a 

 clear, blackwater tributary meets the deeper, 

 murkier Neuse. The river's banks are mud, 



rock and moss, with drifts of purple wildflow- 

 ers. Here, stately cypress stand, their "knees" 

 clutching the earth at the water's edge. 



In lulls between frenzies of 

 electrofishing, migratory birds, newly arrived 

 from more southerly climes, make their 

 presence known. The secretive cuckoo's 

 somber, repetitive call is offset by the ringing 

 melodies of the brown thrush and prothono- 

 tary warbler. It's a transitional time of year at 

 a transitional place. 



Hightower explains what makes the 

 topography here unique. This is an intermedi- 

 ate area between the piedmont and coastal 

 plain. Typically, such a change in gradient is 

 called a fall line, but this is more of a zone 

 than a line, he says. 



"The fall line is important because the 

 habitat changes there," he says. As the river 

 approaches the coastal region from the 

 piedmont, it becomes deeper and slower. The 

 substrate also changes from gravel and cobble 

 above the fall line to sand and silt below. 



"The fall line is sort of ill-defined on the 

 Neuse. It is much more clear-cut on the 

 Roanoke, where the falls at Weldon clearly 

 demarcate the transition between coastal plain 

 and piedmont," Hightower explains. 



By sampling the river bottom, Hightower' s 

 study illustrates why this area is different and 

 why fish tend to migrate here. Below the dam, 

 the substrate is mostly sand and silt — not 

 ideal for spawning, Hightower explains. 



"Gravel and cobble substrate seems to be 

 what fish look for to spawn. Gravel is thought 

 to be good protection for eggs. If the bottom 

 is silty, eggs can suffocate," he says. 



At the sampling area above the former 

 dam site, the substrate changes to gravel and 

 cobble. But above this spawning area, the 

 substrate changes back to mostly sand until 

 near Raleigh, Hightower says, and most 

 USGS maps place the fall line in the 

 Smithfield area. 



"This looks like the next 100 miles," 

 Hightower says, looking downriver. "If you 

 didn't sample bottoms, you wouldn't know 

 why they stop here." 



TOP: Waters and Farmer collect scale 

 samples to determine ages of fish. 



BOTTOM: Hightower samples the river 

 bottom. 



COASTWATCH 15 



