Relative importance of habitat attributes to predation risk in a temperate reef fish (funded by Achievement Rewards for College Scientists; National Undersea Research Program; National Science Foundation; SDSU Master's Program in Ecology)

Christine Gregor's thesis project --

The purpose of Christine's research was to quantify the effects of attributes of habitat architecture on survival of a temperate reef fish, the bluebanded goby, Lythrypnus dalli, and its numerically dominant predator, the kelp bass, Paralabrax clathratus. Christine investigated whether predator-induced mortality of the bluebanded goby was influenced by components of structural habitat complexity using both natural and artificial substrata.

With natural substratum (rocks), survival was positively associated with the size of rock. A major difficulty in investigating attributes of habitat complexity is that they covary and thus are confounded. Consequently, this experiment was followed by a series of experiments using artificial substrata to standardize habitat and hold constant particular variables of structural habitat complexity while others were allowed to vary. Field experiments were conducted to examine the effects of predator access (rock spacing), interstitial space (volume), rugosity, and habitat orientation on predation risk for the bluebanded goby. Each artificial habitat consisted of an array of four-sided “rocks” constructed of PVC such that a specific spatial arrangement created a unique treatment of habitat. Differential survival of gobies occurred with different treatments of habitat. Predator access was more important than interstitial space to survival of the gobies, but both "low" predator access and "low" interstitial volume were required for consistently high survival. Rugosity and habitat orientation, however, did not affect the survival of gobies. Laboratory experiments showed that in the presence of a predator, gobies preferred habitats with low predator access, corresponding to the results obtained from the field. Taken toegether, habitat attributes involving the complexity of rocky substratum, including interstitial space, appears to play an important role in the survival of the bluebanded goby.

This page was last modified on May 19, 2008.

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