Richards, D., Avery, W. and D. Kushner 1993. Kelp Forest Monitoring Annual Report - Channel Islands National Park (1990 Annual Report) Technical Report NPS/WRUC/NRTR-93/05


The 1990 results of the Channel Islands National Park Kelp Forest Monitoring Project are described in this report. Sixty-eight species of algae, fish, and invertebrates were monitored annually at 16 permanent sites around five islands within the park. Survey techniques utilized SCUBA and surface-supplied air, and included quadrats, band transects, random-point contacts, size frequencies, fish and video transects, photogrammetric plots, and species list surveys. In 1990, eight sites had healthy kelp forests, while three others had remnants or signs of developing forest, though dominated by purple sea urchins. Four sites wre dominated by purple sea urchins and one site was dominated by red sea urchins. Four sites had high to moderate densities of white sea urchins, but two of those had dense kelp forests over most of the transect.


As part of the ong-term ecological monitoring, Channel Islands National Park has been conducting monitoring of the kelp forests around Santa Barbara, Anacapa, Santa Cruz, Santa Rosa, and San Miguel Islands since 1982. In 1990, 44 National Park Service and volunteer divers made 759 dives during a series of seven fiv-day and three shorter cruises to conduct the monitoring.

Though originally all sites were kelp forests ten years ago when the monitoring program began, only eight of the 16 permanent sites had healthy kelp forests in 1990. Another site, Cathedral Cove, Anacapa Island had some kelp along the transect and showed signs of recovery though it does not really fit a description of either a kelp forest of urchin barren at present. Four other sites, including all three Santa Barbara sites and Scorpion Anchorage on Santa Cruz were considered purple-urchin barrens, with little algae and more than 40 urchins per square meter. There were signs of kelp forest development nearby to Arch Point and Cat Canyon. Hare Rock on San Miguel Island had an abundance of ephemeral algae and red sea urchins. Fry's Harbor on Santa Cruz Island had an extremely high density of small red sea cucumbers covering the site. ALso on Santa Cruz Island, Pelican Bay was barren of most macro algae and was covered with silt. The purple sea urchin density has declined there in the last few years.

White sea urchin densities were high at four sites: Fry's Harbor and Yellowbanks on Santa Cruz Island, Admiral's Reef on Anacapa Island, and SOutheast Sealion Rookery on Santa Barbara Island. Densities at Fry's Harbor were patchy and generally just below the transect area.

The water around the islands was warmer in 1990. This resulted in an early deterioration of kelp forest canopy by the end of the monitoring season. An increase in the incidence of echinoderms (sea stars, sea cucumbers, and sea urchins) with wasting disease was observed and may also be attributable to the warmer waters. At least three species of sea stars were observed with wasting disease at seven different sites from Anacapa to Santa Rosa Island.

Fish were generally abundant with young-of-year observed for most species monitored. For many fish, 1990 appeared to be a very good recruitment year. Sheephead, kelp bass, rock wrasse, giant kelpfish, and topsmelt were some of the juvenile fish that were noted as especially abundant.

Red abalone abundance continued to decline slightly at most sites. Young abalone were most abundant at Hare Rock and Johnson's Lee North. The abalone at Johnson's Lee North were mostly older than one year.

In a cooperative experiment with the California Department of Fish and Game, abalone recruitment modules were placed out at Yellow Banks, Gull Island, and Johnson's Lee North to test the efficacy of monitoring abalone recruitment. Juvenile hatchery-raised red abalone were placed in modules to test the suitability ofthe modules as habitat. Juvenile native abalone were found using the modules along with various species of fish, sea stars, octopus, and many encrusting invertebrates. After ten months, survival of trasplanted abalone in the modules was best at Johnson's Lee North.

Recommendations evolving from the monitoring program in 1990 include research into improving sampling design, quantifying drift algae and siltation, and conducting regular aerial surveys of the kelp forests for quantification of kelp canopy coverage.

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