(full paper is archived in the Miller Library)
Title: Experimental manipulation of tidepool volumes and its effect on the homing behavior of the woolly sculpin, Clinocottus analis
Student Author(s): Hillegass, Katie Rose
Faculty Advisor(s): Watanabe, Jim
Location: Final Papers Biology 175H
Date: June 2001
Abstract: Previous studies of the woolly sculpin, Clinocottus analis, have revealed homing behavior and site fidelity in this wide-ranging intertidal fish. The purpose of such behavior has been attributed to the increased chance of survival for fishes that can recognize and relocate suitable habitat during the daily fluctuations of submersion within intertidal zone. It should be equally important to the survivorship of fishes to be able to respond to adverse conditions in tidepools to which they home. The purpose of this study was to determine whether C. analis would continue to home under experimental conditions that were expected to be unfavorable, i.e. the periodic draining of the majority of water in tidepools. A field experiment was conducted at Hopkins Marine Station in Pacific Grove, California, during May 2001. Eleven pools between 0.430 m and 1.002 m above MLLW in the moderately-protected region of the intertidal zone were selected and assigned to three treatment groups: an unmanipulated control group, a group that was drained by 78-98% on a daily basis for one week, and a group that was drained by the same amount on three of the seven days of the experimental period. Fish in all pools were marked with subcutaneous paint spots. Pools were surveyed twice during the experiment. Draining was expected to increase maximum pool temperatures, density of fish and other tidepool organisms and decrease rugosity of pools, and all of these changes were observed. Contrary to expectations, fish in all treatments maintained ~34% site fidelity/homing and did not respond in any statistically significant way to experimental treatment. These results imply either that fish were not adversely affected by increased maximum temperatures, densities, and decreased rugosities, or that fish were affected, but homing behavior was not sufficiently plastic within the time-scale of the experiment to show significant treatment effects between pools.