Sanctuary Integrated Monitoring Network
Monitoring Project

Biogeographic Assessment of the Channel Islands National Marine Sanctuary

Summary to Date

The Channel Islands National Marine Sanctuary (CINMS) off the coast of Southern California was designated in 1980. In 2005, NOAA's Office of National Marine Sanctuaries and CINMS were considering six alternatives for adjusting the sanctuary's boundaries. Identifying how the six options overlaid with the distribution of marine resources was a critical consideration. To address this need, we conducted a biogeographic assessment.

No single boundary alternative stood out among the others as a preferred choice, but a couple were favorable for a majority of the biological groups and physical processes and for the composite of all Optimal Area Index analyses.

The overlap of fish and invertebrate habitat suitability appears to be correlated with nearshore environments, predominantly kelp, seagrass beds, and rocky sea floor.

Marine bird and mammal co-occurrence appears to be associated with known centers of upwelling and primary production.

Ecologically important areas of high diversity occur in continental shelf and nearshore waters from Point Conception through the northern Channel Islands, where spatial patterns of bird, fish, invertebrate, and mammal habitat overlap.


The Biogeographic Assessment Framework is a powerful tool for marine resource managers faced with spatially explicit management decisions

The map outputs generated from this assessment have had extended life beyond the comparison of boundary alternatives: Information from this assessment was utilized in California’s Marine Life Protection Act process to inform the placement of marine protected areas (MPAs). The California Coastal Commission has utilized the assessment as a reference guide to examine potential for conflicts with varying activities they have permitted.

Study Parameters

  • Range/Biogeography
  • Currents
  • Diversity
  • Distribution
  • Substrate characterization
  • Temperature
  • Chl A

Study Methods

NCCOS employed the biogeographic assessment framework summarized in Caldow et al (2014). The physical oceanographic, geological and biological resources and habitats were characterized in the context of the six proposed boundary modifications. Data synthesized were assessed for extent, quality, and position relative to these modifications. Geospatial analysis provided map and modelled surfaces that could be compared for each alternative via a series of metrics. Where appropriate, these included an absolute metric (count), a relative metric (density or mean), and a uniquely derived metric (Optimal Area Index). This latter metric or index considers the two other metrics as well as the additional area each alternative would cover. This area estimate is considered a cost.