Date of Award


Document Type


Degree Name

Master of Science




Spawning in five species of North American cyprinid minnows (Rhinichthys a. atratulus, Exog/ossum laurae, Semotilus atromaculatus, Nocomis leptocephalus, and N. micropogon ) are analyzed on videotape filmed in Virginia and Maryland streams. Behaviors are chronologically resolved into a sequence of categories (Interim, Approach, Alignment, Run, Clasp and Dissociation) exemplary of a successful spawn as defined by the clasp. The categories are used to describe spawning behaviors in each species. In all species studied, a successful spawn is a female initiated event effecting the clasping response of a male.

The species-specific pattern of male-female interactions not only reflects the coordination of the spawning clasp, but the architecture of the spawning substrate. In the pebble nest-building cyprinids (i. e., species of Exoglossum, Semotilus and Nocomis ) a successful spawn is the end result of a topographically fixed sequence of behaviors that place the clasped pair over a discrete area of the nest specifically composed for gamete deposition and retention.