Sculpins were collected from spawning grounds by snorkelers using
dip nets and then held without food for 4 days prior to testing. On
the eve of a trial, six sculpins of each species were selected and placed singly, and randomly, in each of the enclosures. A trial consisted of
placing 40 eggs near each sculpin and then collecting and counting all
remaining whole eggs at the end of a 1-h period. To get a more
accurate estimate of what we observed in the wild, only sculpins that
showed a propensity to feed in our chambers were tested. This propensity
was tested by placing a few eggs in a 50-cm-long, 1-cmdiameter
glass tube, with a squeeze ball on one end and a screen
blocking the other end. The eggs were “moved” in front of the sculpin
by lightly squeezing the ball. The sculpins were selected for testing if
they attempted to feed on the available eggs. Most sculpins responded,
but the proportion was not recorded. In addition, 10 sculpins
>70 mm that either did not feed or fed only on one egg during testing
were considered outliers and excluded from the analysis