82 
Burr, Kuhajda, Dimmick, and Grady 
1980s. Further, the extensive trap data involved in collecting biological 
information on Necturus lewisi (Braswell and Ashton 1985) did not 
reveal a single specimen of the sympatric and syntopic Noturus furiosus. 
Collecting conditions were ideal during our field work in May 1985 and 
we concentrated our field efforts on locating only N. furiosus. These 
factors probably contributed to our success. Because we found that N. 
furiosus primarily inhabitats medium- to large-size streams, it is clear 
that the species would be difficult to collect except when water levels are 
low. 
Although N. furiosus is relatively common at some sites, the species 
appears to have experienced a decline and loss of habitat in other areas. 
The greatest losses of N. furiosus habitat have occurred in the Neuse 
drainage. Reservoir construction (Falls Lake), outflow of cold waters 
below Falls Lake, and general pollution problems around Raleigh have 
reduced habitat in the upper Neuse. A toxic chemical spill into the 
Neuse River near Raleigh on 10 July 1980 caused a large fish kill, but 
no N. furiosus were found. The Tar drainage seems to have experienced 
fewer cases of severe habitat degradation. However, the Tar River from 
below Rocky Mount to about 20 km downstream showed evidence of 
extensive municipal and industrial effluents. We did not find N. furiosus 
in that region, and Necturus lewisi is also absent there (Braswell and 
Ashton 1985). 
A number of federal and state projects are presently being completed 
or are in the planning phase for both the Neuse and Tar drainages. 
Most of these projects call for (1) removal of stream cover, (2) denuding 
of stream banks, (3) dredging, (4) channelization, or (5) reservoir 
construction at a number of localities (e.g., Fishing Creek, Tar River 
near Tarboro, Contentnea Creek, Trent River) where N. furiosus is 
known to occur. We predict that these activities will have a detrimental 
effect on the quality of the habitat of N. furiosus, either by changing the 
habitat altogether (e.g., reservoir construction), or by severely modifying 
it (e.g., dredging). 
Natural factors affecting the continued existence of N. furiosus 
include a potential increase in predation owing to desiccation of streams 
during drought. During late summer and fall most streams in the Neuse 
and Tar drainages are reduced to low flow because of little rainfall. The 
riffle habitat of the Carolina madtom is thus restricted in size, and the 
species may be subject to increased predation by fish-eating birds and 
snakes. Adults of other madtoms are eaten only rarely by piscivorous 
fish, and in laboratory experiments they are usually eaten as a last 
choice, probably because of their stout spines and the toxin-producing 
glands associated with the spines (Case 1970). Predators we have 
observed eating other species of adult Noturus on several occasions are 
