Research and Monitoring

      

Kelp Forest and Rocky Subtital Habitats
IV. Human Uses and Impacts

(also see Socioeconomic Uses Section)

Aside from the fisheries which kelp forests support (see III.A.), the kelp forests of California are themselves an important economic and recreational resource. Giant kelp is harvested commercially in both southern and central California, and in the mid-1980's kelp harvesting supported an industry worth more than $40 million a year (Tarpley 1992). Kelp was originally harvested as a source of potash for making gunpowder during World War I (Frey 1971, Tarpley 1992) but currently the emphasis is on the production of algin, which serves as an emulsifying and binding agent in food and pharmaceutical products (Frey 1971) and food for use in abalone farms. Currently between 100,000 and 170,000 wet tons are harvested from California waters each year (Foster and Schiel 1985; Tarpley 1992).

In 1993, more than 4,700 wet tons were harvested from within the MBNMS boundaries, but due to severe thinning of the kelp forests by strong winter storms the following year, only approximately 553 wet tons were harvested in 1994 (P. Reiley pers comm.). At present, Kelco Company of San Diego is the major harvester of kelp in California waters, although the Pacific Kelp Company harvests kelp off central California (Tarpley 1992). Interest in commercial use and concern over kelp harvesting has stimulated considerable research on kelp forests since the late 1950's. In a review, North and Hubbs (1968) reported no adverse effects were observed as a result of kelp harvesting (reviewed in Foster and Schiel 1985). Likewise, Kimura and Foster (1984) found no adverse effects of a single kelp harvest on a kelp forest in Carmel Bay.

In addition to harvesting, the Sanctuary's kelp forests provide an important source of recreational activities, which range from hook-and-line and spear fishing to sport diving and underwater photography (Foster and Schiel 1985). To regulate these activities, a variety of special areas along the coast have been established, some because of their proximity to kelp forests. Marine reserves such as the one at Point Lobos, which was established in 1959 as the nation's first ever marine reserve (Mott 1970) and Hopkins Marine Life Refuge in Monterey Bay, regulate access and restrict fishing and collecting of organisms (Foster and Schiel 1985). These reserves may serve as valuable natural baselines to measure impacts of human activities, such as those described in I.B., in less protected MBNMS kelp forests.

We probably know more about kelp forests in the Monterey Bay area than anywhere else in the world except southern California. However, knowledge is lacking on the kelp forests south of Carmel Bay and north of Santa Cruz, and many processes are still poorly understood, e.g. the effects of local fisheries on kelp forest fish populations. Considerable research currently in progress at several institutions within the MBNMS addresses issues like these; the results will greatly enhance our understanding of the structure and dynamics of the kelp forests of the Monterey Bay National Marine Sanctuary.

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