Benthic Habitats and the Effects of Fishing

Refining Estimates of Potential White Abalone Habitat at Northern Anacapa Island, California Using Acoustic Backscatter Data

Guy R. Cochrane, John L. Butler, and Gary E. Davis

doi: https://doi.org/10.47886/9781888569605.ch14

Abstract.—Acoustic backscatter data provides exceptional detail of rocky seafloor habitat on the continental shelf north of Anacapa Island off Southern California. In the depth range of 25–65 m, there are approximately 60 ha of rocky bottom which may be suitable for abalone Haliotis spp. The distribution of rocky bottom is divided into two separate areas on the northeastern and northwestern sides of the island, which are separated by a central area of predominantly sandy bottom. The northeastern area has a far greater area of rocky bottom. When habitat estimation is restricted to the perimeter of rocky areas, the difference in habitat area between the east and west lessens. The northeastern area may be more attractive for seeding of white abalone Haliotis sorenseni because it has more rocky bottom and recently has been designated as a marine reserve with no fishing, whereas the northwestern area is now a marine conservation area with limited fishing. This methodology will help locate sites for planting of captive-bred white abalone as part of the white abalone restoration project if numerous other requirements for the abalone, such as food sources, are mapped also.