Masters Thesis

Determining Population Structure, Reproductive Potential, and Habitat Associations of Pinto Abalone (haliotis Kamtschatkana) in Southern California

This study provides the first assessment of demographic and habitat information for pinto abalone (Haliotis kamtschatkana) in San Diego, California, two decades after the closure of all abalone fisheries in southern California. SCUBA surveys conducted from June 2014 to December 2016 indicate that current low densities (0-0.03 individuals/m2) were far below critical thresholds identified for other abalone species (0.15-0.30 abalone/m2) for successful spawning and recruitment. a broad range of sizes were represented (13-146 mm), however, only 95 individuals were found. Some sites showed significant aggregation of adult (> 50 mm) pinto abalone, 30% of adults had a nearest-neighbor within a critical spawning distance of 2 m, and 65% had a neighbor within 5 m, indicating that at least a small proportion of individuals may be capable of reproducing successfully. Pinto abalone showed a significant preference for boulder habitat at a lower relief (< 10 cm) relative to available habitat– a preference that may influence aggregation around habitat features and enhance reproduction. the frequency, timing, and broad spatial distribution of these surveys was not sufficient to measure patterns in recruitment or changes in abundance, particularly over a strong El Niño event that occurred during the study period. There is a critical need for consistent long-term monitoring in southern California to better understand demographic and environmental processes affecting recovery and persistence of populations, particularly at the southern edge of the broad range of pinto abalone.

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