Research Technical Report

Diver Disturbance in Kelp Forests

Schaeffer, T.N., and M. Foster (December 1997)

Presentation at Western Society of Naturalists Annual Meeting, Monterey, CA

ABSTRACT

Recreational SCUBA diving activity has increased dramatically in the past 20 years, with the potential for causing important disturbance to subtidal reefs. While diver disturbance on coral reefs has been assessed in a number of studies, effects on kelp forests have not been previously examined. We estimated diver disturbance in southern Monterey Bay giant kelp forests by following 43 divers in summer, 1997. During a 0.5 hr dive, the average diver contacted the bottom 43 times, touched 4 animals, and detached 2 algal blades. The concentration of large numbers of divers in local, usually wave-protected kelp forests could lead to permanent alterations in community structure. Such impacts might be mitigated through better training and the designation of underwater training areas, and should be considered in proposals to establish and manage marine protected areas.