Over 30 DFG personnel completed 82 underwater transects to count and measure abalone, urchin, and starfish around the John V. Fitzgerald Marine Reserve (FMR). Divers spent three days in September off Half Moon Bay on the San Mateo coast to learn more about why abalone sport diver success has plummeted there in recent years. Field surveys of sport divers and shorepickers show catch rates of only 1.0 to 1.2 compared to 2.1 abalone-per-hour reported in this area in the 1960s. In contrast, the abalone fishery off Mendocino and Sonoma Counties sustains rates of 2.2 to 3.1 abalone-per-hour. Field surveys of sportsmen off FMR conducted by San Mateo Park rangers have shown total effort and take declined by 50% from 1972 to 1992.
Our divers chose to participate, knowing fully well that only two weeks earlier a sea otter had washed ashore, mortally wounded by a great white shark. Sharks are found at higher concentrations in the "red triangle" (from Año Nuevo, 20 miles south of FMR, to Bodega Bay, and the Farallon Islands off San Francisco) and may be one reason why otters have not become re-established north of Año Nuevo. Unusually calm seas allowed work to be completed at all but the shallowest stations with depths surveyed from 13.5 to 60.2 feet. Seven different locations were surveyed off FMR at three target depths: Shallow (20 ft.), Medium (35 ft.) and Deep (55 ft.) using both emergent and invasive transects. Emergent transects covered 60 square-meters and counted exposed animals. Invasive transects covered only 10 square-meters but were made more thorough with flashlights and the moving of rocks and boulders.
Abalone densities were remarkably low relative to other northern California areas while urchin densities were typical of fished areas in the north. Emergent shallow stations produced only 0.04 abalone per square meter (one abalone per 90 square yards)or about five times rarer then the lowest density locations in northern California from a 1986 DFG survey. The situation in deeper water worsens; medium stations averaged 0.002 abalone-per-square-meter (one abalone per 1800 square yards) and no abalone were found at deep water stations. In the emergent transects only 28 abalone were found and measured out of 1458 square-meters searched. Abalone lengths ranged from 2.2 to 7.9 inches and averaged 5.5 inches. Only three sport legal (>7 inches) and one commercial legal (>7.75 inches) abalone were found! A total of 44 abalone were measured in the invasive transects. These averaged 5.0 inches and ranged from 0.9 to 7.6 inches (14 of these were sport legal).
Sportsmen have expressed concern about the resource decline off the San Mateo coast, arguing that commercial divers are allowed to use hooka (surface supplied air) while sportsmen must freedive. Exacerbating the user conflict was recent legislation (AB 3705) that allowed commercial divers to fish inside 20-foot depths off the San Mateo coast. - KK
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