Habitat-dependent recruitment of two temperate reef fishes at multiple spatial scales (funded by California Sea Grant; Mabel Myers Memorial Scholarship; SDSU Master's Program in Ecology)

Kelly Andrews's thesis project --

Kelly Andrews determined whether habitat-dependent recruitment occurred for two temperate reef fishes at multiple spatial scales. Recruitment of the California sheephead (Semicossyphus pulcher) and the blackeye goby (Rhinogobiops nicholsii) were recorded on surveys of 21 quarry-rock reef modules at San Clemente Artificial Reef (SCAR) for a 2-year period (2001-02). Among reef modules, data on recruitment of these two species were collected by SCUBA divers that swam four transects on each of the 21 modules. While swimming along the bottom, new recruits of each species were recorded, along with estimates of abundance of predators (kelp bass and barred sand bass). These data provided estimates of recruitment to the different treatments of habitat coverage and an index of predation risk.

Within reef modules, recruitment was recorded along the 'edge' vs. 'interior' of the modules. At a smaller spatial scale, microhabitat associations of the California sheephead and the blackeye goby were examined by censusing variables of microhabitat structure within 1 m x 1 m quadrats. Variables included percentage cover of substratum (rock, mudstone, sand, and algae), vertical relief, and rugosity (an index of topography).

Microhabitat availability was quantified by random selection of several points within each module and recording the microhabitat characteristics in a 1 m² area. Microhabitat characteristics in 1 m x 1 m quadrats were also quantified where a fish was located on the a module. These data were then analyzed to determine if there were differences between microhabitat availability and use by recruits.

These results provide valuable information to regional agencies or managers that are charged with identifying essential fish habitat. This information is especially needed for the California sheephead due to its commercial and recreational importance as a near shore fishery.

This page was last modified on April 24, 2007.

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