Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply endorsement by the 

U.S. Government

This map was printed on an electronic plotter directly from digital files. Dimensional calibration may vary between electronic plotters 

and between X and Y directions on the same plotter, and paper may change size due to atmospheric conditions; therefore, scale and 

proportions may not be true on plots of this map.

For sale by U.S. Geological Survey, Information Services, Box 25286, Federal Center, Denver, CO 80225, 1–888–ASK–USGS

Digital files available at http://dx.doi.org/10.3133/ofr20151232

Suggested Citation: Endris, C.A., Greene, H.G., Dieter, B.E., and Erdey, M.D., 2015, Potential marine benthic habitats, Offshore of 

Pigeon Point map area, California, sheet 7 in Cochrane, G.R., Watt, J.T., Dartnell, P., Greene, H.G., Erdey, M.D., Dieter, B.E., Golden, 

N.E., Johnson, S.Y., Endris, C.A., Hartwell, S.R., Kvitek, R.G., Davenport, C.W., Krigsman, L.M., Ritchie, A.C., Sliter, R.W., Finlayson, D.P., 

and Maier, K.L. (G.R. Cochrane and S.A. Cochran, eds.), California State Waters Map Series—Offshore of Pigeon Point, California: 

U.S. Geological Survey Open-File Report 2015–1232, pamphlet 40 p., 10 sheets, scale 1:24,000, http://dx.doi.org/10.3133/ofr20151232.

ISSN 2331-1258 (online) 

http://dx.doi.org/10.3133/ofr20151232

US Army Corps

of Engineers

Figure 1. Map showing video-observation locations and sample localities for Offshore of Pigeon Point map 

area.

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122°25' 122°20'

37°10'

37°5'

3-nautical-mile limit of California’s State Waters

# Sample locality

Bathymetric contours—Derived from modified 

10-m-resolution bathymetry grid. Contour interval: 10m

Habitat interpretation outline

! Video observation

Approximate modern shoreline—Defined as

Mean High Water (MHW) (+1.33 m), North

American Vertical Datum of 1988 (NAVD 1988)

EXPLANATION

37°

36°40'

122°20' 122°

Santa Cruz

Monterey

Moss 

Landing

Pigeon

Point

Limit of California’s

State Waters

Area of

Map

CALIF.

MAP LOCATION

0 5 10 Kilometers

0 5 10Nautical Miles

121°40'

Monterey

Bay

20

Sh(b)/p_c

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DESCRIPTION OF MAP UNITS

UNCONSOLIDATED CONTINENTAL SHELF SEDIMENTS

Soft, unconsolidated sediment (fine sand and mud), predominantly rippled

Soft, unconsolidated sediment (sand), predominantly rippled

Unconsolidated, dynamic mound of soft sediment (sand)

Soft, unconsolidated rippled sediment (sand and gravel)

Soft, mobile sediment window that has unconsolidated and rippled sediment waves, 

overlying scoured lag pavement of sand and gravel (sorted bedforms)

MIXED SUBSTRATE ON CONTINENTAL SHELF

Mixed habitat of soft, unconsolidated sediment, overlying hard, consolidated 

sedimentary bedrock

HARD SUBSTRATE ON CONTINENTAL SHELF

Deformed and differentially eroded, consolidated sedimentary-bedrock outcrop

Hard, consolidated sedimentary rock, boulders, or pinnacle

Hard, consolidated boulders or pinnacles of sedimentary rock; inferred

EXPLANATION OF MAP SYMBOLS

Contact

Area of “no data”—Areas near shoreline not mapped owing to insufficient highresolution seafloor mapping data; areas beyond 3-nautical-mile limit of California’s 

State Waters were not mapped as part of California Seafloor Mapping Program

3-nautical-mile limit of California’s State Waters

Bathymetric contour (in meters)—Derived from modified 2-m-resolution bathymetry 

grid. Contour interval: 10 m

DISCUSSION

This map shows “potential” marine benthic habitats in the Offshore of Pigeon Point map area. Marine 

benthic habitats represent a particular type of substrate, geomorphology, seafloor process, or any other attribute 

that may provide a habitat for a specific species or an assemblage of organisms. Such maps are based largely on 

seafloor geology, and this map integrates seafloor geology (sheet 10) with information depicted on several other 

thematic maps of the Offshore of Pigeon Point map area: high-resolution bathymetry (sheet 1); shaded-relief 

imagery (sheet 2); backscatter (sheet 3); seafloor character (sheet 5); and ground-truth information (sheet 6). This 

map also uses information from the usSEABED bottom-sampling compilation by Reid and others (2006). The 

combination of remotely observed data (for example, multibeam bathymetry and backscatter, seismic-reflection 

profiles) and directly observed data (for example, camera transects, sediment samples) translates to higher 

confidence in the ability to interpret broad areas of the seafloor (fig. 1).

To avoid any possible misunderstanding of the term “habitat,” the term “potential habitat” (as defined by 

Greene and others, 2005) is used herein to describe a set of distinct seafloor conditions that in the future may 

qualify as an “actual habitat.” Once habitat associations of a species are determined, they can be used to create 

maps that depict actual habitats, which then need to be confirmed by “ground-truth” surveying using in situ 

observations, video, and (or) photographic documentation. 

Marine benthic habitats are classified using the Benthic Marine Potential Habitat Classification Scheme, a 

mapping-attribute code developed by Greene and others (1999, 2007). In this map series, habitat-classification 

codes are based on the deepwater habitat-characterization scheme developed by Greene and others (1999), which 

was created to not only easily distinguish marine benthic habitats but also to facilitate ease of use and queries 

within GIS and database programs. The code, which is summarized in chapter 6 in the accompanying pamphlet, 

is derived from several categories of the Benthic Marine Potential Habitat Classification Scheme (Greene and 

others, 1999, 2007), and it can be subdivided on the basis of the spatial scale of the data. 

High-resolution, multibeam-sonar data, converted to bathymetric depth grids (seafloor digital elevation 

models; sheet 1), are essential to development of the habitat map, as is shaded-relief imagery (sheet 2), which 

allows for visualization of seafloor terrain, and provides a foundation for interpretation of submarine landforms. 

Areas of seafloor bedrock exposures are identified by their common sharp edges and high relative relief; these 

may be contiguous outcrops, isolated parts of outcrop protruding through sediment cover (pinnacles or knobs), or 

isolated boulders. 

Backscatter maps (sheet 3) also are essential for developing potential benthic habitat maps. High backscatter 

is further indication of “hard” bottom, consistent with interpretation as rock or coarse sediment. In many 

locations, areas within or around a rocky feature appear to be covered by a thin veneer of sediment, identified on 

the habitat map as “mixed” induration (in other words, containing both rock and sediment). Broad, generally 

smooth areas of the seafloor that lack sharp and angular edge characteristics are mapped as “sediment” and are 

further defined by various sedimentary features such as erosional scours and depressions, as well as depositional 

features such as dunes, mounds, or sand waves. Low backscatter, indicative of a “soft” bottom, also significantly 

aids identification and classification of sedimentary habitats.

The Offshore of Pigeon Point map area includes the nearshore and inner shelf areas from just north of 

Pigeon Point to Point Año Nuevo. Delineated on the map are 9 potential marine benthic habitat types, all of 

which are located on the continental shelf (“Shelf” megahabitat). The meso- and macrohabitats include soft 

unconsolidated sediment (5 habitat types) such as fine sand and mud, sand, and dynamic features such as mobile 

sand sheets, sediment waves, and rippled sediment depressions; mixed substrate (1 habitat type) such as soft sand 

and gravels overlying consolidated sedimentary bedrock and gravel pavement; and hard substrate (3 habitat 

types) such as deformed and differentially eroded bedrock, as well as pinnacles and boulders. 

Acoustic-backscatter data (see sheet 3) show that most of the area is underlain by “soft” materials, consistent with the interpretation that unconsolidated sediments dominate habitat in the mapped area. Sedimentary 

processes are quite active and, thus, habitats are highly dynamic, with sediment transport primarily to the 

southeast. An extensive exposure of deformed and differentially eroded bedrock is found offshore of Point Año 

Nuevo, and it potentially provides good habitat for rockfish (Sebastes spp.).

Of the 134.34 km2

 on the continental shelf in the map area, soft, unconsolidated sediment is the dominant 

habitat type, covering 108.36 km2 (80.7 percent). Hard rock covers 22.78 km2 (17.0 percent), whereas 3.19 km2

(2.4 percent) consists of mixed hard-soft substrate.

REFERENCES CITED

Greene, H.G., Bizzarro, J.J., O’Connell, V.M., and Brylinsky, C.K., 2007, Construction of digital potential 

marine benthic habitat maps using a coded classification scheme and its application, in Todd, B.J., and 

Greene, H.G., eds., Mapping the seafloor for habitat characterization: Geological Association of Canada 

Special Paper 47, p. 141–155. 

Greene, H.G., Bizzarro, J.J., Tilden, J.E., Lopez, H.L., and Erdey, M.D., 2005, The benefits and pitfalls of 

geographic information systems in marine benthic habitat mapping, in Wright, D.J., and Scholz, A.J., eds., 

Place matters: Portland, Oregon State University Press, p. 34–46.

Greene, H.G., Yoklavich, M.M., Starr, R.M., O’Connell, V.M., Wakefield, W.W., Sullivan, D.E., McRea, J.E., 

and Cailliet, G.M., 1999, A classification scheme for deep seafloor habitats: Oceanologica Acta, v. 22, p. 

663–678.

Reid, J.A., Reid, J.M., Jenkins, C.J., Zimmerman, M., Williams, S.J., and Field, M.E., 2006, usSEABED—

Pacific Coast (California, Oregon, Washington) offshore surficial-sediment data release: U.S. Geological 

Survey Data Series 182, available at http://pubs.usgs.gov/ds/2006/182/.

1

Moss Landing Marine Laboratories, Center for Habitat Studies;

2

U.S. Geological Survey 

Potential Marine Benthic Habitats, Offshore of Pigeon Point Map Area, California

By

Charles A. Endris,1 H. Gary Greene,1 Bryan E. Dieter,1 and Mercedes D. Erdey2

2015

ONE MILE = 0.869 NAUTICAL MILES

BATHYMETRIC CONTOUR INTERVAL 10 METERS

1 .5 0 1 KILOMETER

1000 0 1000 2000 3000 4000 5000 6000 7000 FEET

1 1/2 0 1 MILE

SCALE 1:24 000

APPROXIMATE MEAN

DECLINATION, 2015

MAGNETIC NORTH

13 / ° 1 2

TRUE NORTH

Potential marine benthic habitats mapped by Bryan E. Dieter, Charles 

A. Endris, and H. Gary Greene, 2011. Bathymetric contours by 

Mercedes D. Erdey, 2014

GIS database and digital cartography by Mercedes D. Erdey and 

Bryan E. Dieter

Manuscript approved for publication December 4, 2015

Onshore elevation data from California Coastal Conservancy (available 

from National Oceanic and Atmospheric Administration [NOAA] 

Coastal Service Center’s Digital Coast at http://www.csc.noaa.gov/

digitalcoast/data/coastallidar/) and from U.S. Geological Survey’s 

National Elevation Dataset (available at http://ned.usgs.gov/). Offshore 

shaded-relief bathymetry from map on sheet 2, this report. California's 

State Waters limit from NOAA Office of Coast Survey

Universal Transverse Mercator projection, Zone 10N

NOT INTENDED FOR NAVIGATIONAL USE

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122°20'

122°20'

122°25'

122°25'

37°10'

37°10'

37°05'

37°05'

Point 

Año Nuevo

Pigeon Point

Open-File Report 2015–1232

Sheet 7 of 11

Pamphlet accompanies map

U.S. Department of the Interior

U.S. Geological Survey