National Park Service

Mediterranean Coast Network (MEDN)

Kelp Forest Monitoring

Underwater view of kelp forest
Underwater view of kelp forest

Kelp Forest Community Resource Briefs

Kelp Forest Community Monitoring Reports

Kelp Forest Community Protocol Documents

For more information contact: David Kushner or Joshua Sprague


The nearshore waters along the coastline southern California host one of the most productive marine ecosystems on earth, giant kelp forests (Macrocystis pyrifera). Like tropical rainforests, these towering seaweeds provide structure, food, and hiding places for more than 1,000 species of plants and animals, providing necessary habitat for species as diverse as giant black sea bass and tiny bluebanded gobies.

Kelp forests are influenced by both natural events and human activities. Strong storms associated with El Niño years and fluctuating water temperatures can cause dramatic changes in kelp forest communities. Human activities also affect the health and survival of kelp forests through coastal development, sedimentation, pollution, and, in particular, fishing. Removal of predators can alter predator-prey interactions. For example,with the elimination of sea otters, and the overharvesting of spiny lobster and California sheephead, herbivore populations like purple sea urchins can increase decimate kelp beds through overgrazing. These areas quickly transition into "barren" landscapes supporting relatively few species and lower biomass. Loss of kelp beds also eliminates nursery grounds for many species whose young live in the kelp until they are large enough to venture into open waters. Without shelter and food from the kelp forest, these populations may be dramatically reduced.

Monitoring Efforts

The Kelp Forest Monitoring Program was established by Channel Islands National Park in 1982 to collect baseline information about the kelp forest ecosystem in the Park. Each year the program collects size and abundance data for 70 categories (taxa) of algae, invertebrates and fish that are indicators of ecosystem health.

Monitoring Objectives

The current protocol was adopted in 1997. The objectives of the kelp forest monitoring effort are to:

  • Determine the status and health of the islands' kelp forests
  • Document the types of changes occurring in the marine environment
  • Develop management strategies needed to protect the kelp forest ecosystem

Management Implications

Park researchers have documented widespread and dramatic changes in the marine ecosystem around the Channel Islands since the program began, including declines in fished species like abalone and the loss of kelp beds around several of the islands.

  • Information from park monitoring was instrumental in establishing marine reserves, areas of the ocean granted complete protection from fishing and extractive activities, at the Channel Islands, placing nearly 20% of Park waters into state marine protected areas.
  • In 2008, a 5-year review of data collected by the Park and others demonstrated some positive trends in the new marine reserves including:
    • greater overall biomass inside reserves
    • larger average body size of some species like kelp bass and spiny lobster in unfinished reserves
    • kelp beds around the Channel Islands have recently increased, after experiencing substantial declines in the 1980s and 1990s

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Last Updated: December 30, 2016 Contact Webmaster