SEASONAL-CHANGES IN THE SOCIAL-STRUCTURE OF A MOTTLED SCULPIN (COTTUS-BAIRDI) POPULATION

Adult male mottled sculpins (Cottus bairdi) were solitary during the breeding season (April to June) and the following summer. Gravid females were randomly distributed with respect to one another, but were most frequently found with males that had previously mated. In addition, the number of egg masses found at certain sites was far greater than expected on the basis of chance matings. These patterns suggest that females visited several spawning sites before breeding, and that certain sites or males were more attractive than others. Although unsexable individuals were randomly dispersed they were rarely found at sites occupied by adult males. This pattern may reflect the influence of intraspecific predation of larger sculpins on smaller conspecifics. © 1979.