Nest Associates of Nocomis leptocephalus 79 



interaction mutualistic, parasitic, or commensal? How did this behavior 

 evolve? 



Several authors have suggested that nest association occurs because 

 of the absence of suitable spawning substrate elsewhere in the stream or 

 pond (Latta 1958, McAuliffe and Bennett 1981, Starnes and Starnes 

 1981.) If that is the case, associates such as the species described in this 

 paper would be expected to be attracted to and to use suitable nests in 

 the absence of the host. 



The experiment reported here was conducted with spawning 

 associations of N. leptocephalus in North Carolina to determine whether 

 nest association is a response to the clean mounds of gravel built by 

 Nocomis or a response to other factors associated with nests. Gravel 

 nests, similar to those of Nocomis, were constructed in areas of suitable 

 depth and flow and checked for use by spawning fishes. The results of 

 this experiment are discussed, and spawning activities of the three nest 

 associates (N. ehloroeephalus, N. chiliticus, and H. hypsinotus) are 

 described. 



MATERIALS AND METHODS 



Spawning associations of Notropis ehloroeephalus, Luxilus 

 coccogenis (Cope), Clinostomus funduloides Girard, Campostoma 

 anomalum (Rafinesque), and Nocomis leptocephalus were observed in 

 two streams in the Catawba River, McDowell Co., N.C., on 26 and 27 

 May 1987, from 10 to 13 May 1988, and from 24 to 27 May 1988. 

 Spawning aggregations of Notropis chiliticus and Hybopsis hypsinotus 

 were observed over N. leptocephalus nests in the Fisher River, Surry 

 Co., N.C., on 26 May 1988. 



Observations of spawning fishes were made by snorkeling or from 

 above the water by using binoculars or polarized sunglasses. Height 

 (distance from substrate to nest top), width (perpendicular to stream 

 flow), and length (parallel to stream flow) of active and artificial nests 

 were measured, along with water depth and surface flow (cm/ sec). 

 Surface flow was measured by timing the progress of an object over a 

 known distance. 



To simulate Nocomis nests, clean gravel of the sizes used in the 

 nests was collected from the stream bed, rinsed, and piled in mounds 

 similar in shape and size to nests in areas similar in depth and flow to 

 those where active Nocomis nests occurred. In some cases artificial nests 

 were built in the previous locations of Nocomis nests. 



RESULTS 



Spawning behaviors in Notropis ehloroeephalus and N. chiliticus 

 were very similar. Spawning occurred at water temperatures of 11- 



