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://pubs.usgs.gov/sim/3254/

Suggested Citation: Endris, C.A., Greene, H.G., and Golden, N.E., 2013, Potential marine benthic habitats, Offshore of Ventura map area, California, sheet 7 in Johnson, S.Y., Dartnell, P., Cochrane, 

G.R., Golden, N.E., Phillips, E.L., Ritchie, A.C., Kvitek, R.G., Greene, H.G., Krigsman, L.M., Endris, C.A., Seitz, G.G., Gutierrez, C.I., Sliter, R.W., Erdey, M.D., Wong, F.L., Yoklavich, M.M., Draut, A.E., and 

Hart, P.E. (S.Y. Johnson and S.A. Cochran, eds.), California State Waters Map Series—Offshore of Ventura, California: U.S. Geological Survey Scientific Investigations Map 3254, pamphlet 42 p., 11 

sheets, scale 1:24,000, available at http://pubs.usgs.gov/sim/3254/.

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119°25' 119°20'

34°20'

34°15'

EXPLANATION

Approximate modern shoreline—Defined as

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

American Vertical Datum of 1988 (NAVD 1988)

! Video observation

# Sample locality

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

Bathymetric contours—Derived from modified

10-m-resolution bathymetry grid. Contour

interval: 10m

Habitat interpretation outline

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

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DESCRIPTION OF MAP UNITS

UNCONSOLIDATED CONTINENTAL SHELF SEDIMENTS

Soft, unconsolidated rippled sediment (sand); inferred

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

Pockmarks or depressions in soft, unconsolidated sediment (sand and mud)

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

scoured lag pavement of sand and gravel

Soft, unconsolidated sediment (sand and gravel) on flat shelf

Hummocky, unconsolidated sediment (sand and gravel)

Soft, unconsolidated sediment mound

HARD SUBSTRATE

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

Hard, consolidated sedimentary-bedrock outcrop

Hard, consolidated sedimentary rock, boulders, or pinnacle

ANTHROPOGENIC FEATURES

Anthropogenically deposited, unconsolidated sediment (sand and gravel), in dredge mound adjacent to 

man-made island (Rincon Island)

Mound of soft, unconsolidated sediment overlying hard anthropogenic feature (pipeline)

Linear depression in soft, unconsolidated sediment overlying hard anthropogenic feature (pipeline)

Hard anthropogenic feature (groin or jetty)

Hard anthropogenic feature (pipeline)

EXPLANATION OF MAP SYMBOLS

Contact

Area of “no data”—Areas near shoreline not mapped owing to insufficient high-resolution 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 10-m-resolution bathymetry grid. Contour 

intervals: 10 m

DISCUSSION

This map shows “potential” marine benthic habitats in the Offshore of Ventura 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 Ventura map area: high-resolution bathymetry (sheets 1, 2); 

backscatter (sheet 3); shaded-relief-profile imagery (sheet 4); seafloor character (sheet 5); and ground-truth information (sheet 6). This 

map also uses information from 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. 

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 habitatcharacterization 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; sheets 1, 2), are 

essential to development of the habitat map. Shaded-relief-profile imagery (sheet 4) allows for visualization of seafloor terrain, providing 

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. 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 Ventura map area contains 15 potential marine benthic habitat types, which range from primarily soft, unconsolidated sediment (mud to sand and gravel) to hard bedrock exposures. Sedimentary-bedrock outcrops (some partly covered with sediment 

to produce a mixed hard-soft habitat type), pockmarks, and mounds complete the variety of habitats identified in the map area. 

The soft, unconsolidated sediment habitat, which includes pockmarks and mounds, covers 97.7 km2

 of the map area, representing 

97.2 percent of all of the potential habitat types identified. Sediment-covered bedrock, which includes the mixed hard-soft habitat type, 

covers 0.13 km2 (0.1 percent). Areas where the soft, unconsolidated sediment is rippled and dynamic cover about 2.37 km2 (2.4 percent). 

Hard bedrock exposures cover 0.24 km2 (0.2 percent), whereas anthropogenic features cover less than 0.1 km2 (<0.1 percent).

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: Canadian Geological Association 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/.

CALIF.

0 4 8 Nautical Miles

Kilometers 0 5 10

120° 119°40' 119°20' 119°

34°

34°20'

MAP LOCATION

Ventura

Santa Barbara

Anacapa

Island

Santa Cruz Island Santa Rosa Island

Area of

Map

Santa Barbara Channel

Limit of California’s

State Waters

1

Moss Landing Marine Laboratories, Center for Habitat Studies;

2

U.S. Geological Survey 

Potential Marine Benthic Habitats, Offshore of Ventura Map Area, California

By

Charles A. Endris,1 H. Gary Greene,1 and Nadine E. Golden2

2013

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, 2013

MAGNETIC NORTH

12 / ° 1 2

TRUE NORTH

Potential marine benthic habitats mapped by Charles A. 

Endris, H. Gary Greene, and Nadine E. Golden, 2011. 

Bathymetric contours by Andrew C. Ritchie, 2011

GIS database and digital cartography by Charles A. 

Endris, Nadine E. Golden, and Mercedes D. Erdey

Edited by Taryn A. Lindquist

Manuscript approved for publication March 11, 2013 

Onshore elevation data from NOAA Coastal Services 

Center (data collected by EarthData International in 

2002-2003). California's State Waters limit from NOAA 

Office of Coast Survey

Universal Transverse Mercator projection, Zone 11N

NOT INTENDED FOR NAVIGATIONAL USE

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Ventura

Santa Clara

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Ventura Harbor

119°25' 119°20' 119°15'

119°25' 119°20’

34°15'

34°20'

34°15'

34°20'

Scientific Investigations Map 3254 

Sheet 7 of 11

Pamphlet accompanies map

U.S. Department of the Interior

U.S. Geological Survey