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: Golden, N.E., Cochrane, G.R., and Krigsman, L.M., 2015, Ground-truth studies, Offshore of Pigeon Point map area, 

California, sheet 6 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

Figure 6. USGS-designed camera sled being launched off research vessel in preparation for ground-truth studies. 

Components onboard sled include four digital video camcorders, one 8-megapixel digital SLR camera, lasers for scale, and 

various strobe and video lights, as well as telemetry instrumentation that records depth, altitude, and compass heading.

#

^

^

^

^

!

!

!

!

DISCUSSION

Between 2006 and 2007, the seafloor in the Offshore of Pigeon Point map area in central California was mapped by California State 

University, Monterey Bay (CSUMB), by Fugro Pelagos, and by the U.S. Geological Survey (USGS), using both multibeam echosounders and 

bathymetric sidescan-sonar systems (see sheets 1, 2, 3). These mapping missions combined to collect bathymetry and acoustic-backscatter data 

from about the 10-m isobath to out beyond the 3-nautical-mile limit of California’s State Waters. In order to characterize the bathymetry and 

acoustic-backscatter data into geologically and biologically useful information, the USGS ground-truth-surveyed the data by towing a camera 

sled (fig. 6) over specific locations throughout the map area in 2007 and 2012.

During the ground-truth-survey cruises, the camera sled was towed 1 to 2 m above the seafloor, at speeds of between 1 and 2 nautical 

miles/hour. The sled housed two standard-definition (640×480 pixel resolution) video cameras (one forward looking, the other downward 

looking), a high-definition (1,080×1,920 pixel resolution) video camera, and an 8-megapixel digital still camera, which captured a digital still 

photograph once every 30 seconds. The video was relayed in real time to the research vessel, where USGS and National Oceanic and Atmospheric Administration (NOAA) scientists recorded both the geologic and biologic character of the seafloor once every minute, using programmable keypads. The locations and directions of the camera-sled tracklines were chosen in order to visually inspect areas thought to represent the 

full range of bottom hardness and rugosity in the map area.

In the context of marine-fisheries management, benthic-habitat complexity can be divided into abiotic (geologic) and biotic (biologic) 

components. Benthic-habitat complexity refers to the visual classification of local abiotic and biotic vertical relief and structure that may 

provide potential refuge for both juvenile and adult forms of various species. Only abiotic attributes (primary- and secondary-substrate composition) were used in the production of the seafloor-character map on sheet 5. Classifications of primary and secondary substrate are based on the 

Wentworth (1922) scale of sediment grain-size categories, and the sand, cobble, and boulder sizes are classified as in Wentworth (1922). 

However, the difficulty in distinguishing the finest divisions in the Wentworth (1922) scale during video observations made it necessary to 

aggregate some grain-size classes: the granule and pebble sizes have been grouped together into a class called “gravel,” and the clay and silt 

sizes have been grouped into a class called “mud.” In addition, hard bottom and clasts larger than boulder size are classified as “rock.” Primary 

and secondary substrate, by definition, constitute greater than 50 and 20 percent of the seafloor during an observation, respectively.

This sheet contains a smaller, simplified (depth-zone symbology has been removed) version of the seafloor-character map (sheet 5), on 

which the camera-sled tracklines used to ground-truth-survey the sonar data are indicated by aligned colored dots, each dot representing the 

location of a recorded observation. Primary- and secondary-substrate compositions are shown by differently colored dots. The map also shows 

the locations of the detailed views of seafloor character along some of the tracklines (Boxes A through E) that are highlighted on this sheet 

(figs. 1A, 2A, 3A, 4A, 5A). Also shown are locations of samples (triangles) from usSEABED (Reid and others, 2006) that were used to 

supplement the ground-truth surveys. The seafloor-character map shows that this area is predominantly high-relief, rocky and bouldery habitat 

in the nearshore, out to depths of as much as 45 m, and low-relief sand and mud habitat in deeper waters.

Each detailed view (figs. 1A, 2A, 3A, 4A, 5A) shows the locations of camera-sled tracklines (aligned colored dots), as well as of the 

photographs (colored stars) taken along the tracklines. These photographs, which are representative of the seafloor, are displayed with a 

description of the observed seafloor characteristics recorded by USGS and NOAA scientists (figs. 1B, 1C; 2B through 2E; 3B through 3L; 4B 

through 4H; 5B through 5D). Only primary and secondary substrates are reported, although individual photographs may show more substrate 

types. Organisms, when present, are labeled on the photographs.

Ground-truth surveys in the Offshore of Pigeon Point map area include approximately 8 trackline kilometers of video and 1,410 still 

photographs, in addition to 390 seafloor observations of abiotic and biotic attributes. A visual estimate of slope also was recorded.

GLOSSARY

Rugosity—A GIS-derived characterization of seafloor roughness, calculated as the ratio of the three-dimensional surface area of seafloor to 

the two-dimensional planar-base area, for each cell in the bathymetry grid.

Backscatter intensity—The amplitude of the reflected sonar signal (see sheet 3) used to infer the hardness of the bottom, determined after 

sonar-data processing has removed (as much as possible) the effects of water depth, angle of reflection, and bottom roughness.

Biocomplexity—The assessment of the presence or absence of biological structures that have the potential of providing shelter for fauna, 

determined by estimating the scale, the amount, and the morphology of biological relief (as described by Tissot and others, 2006).

Biocover—The visual estimate of the proportion of biologic cover by encrusting organisms: high, greater than 50 percent; moderate, 

between 50 percent and 10 percent; low, less than 10 percent.

REFERENCES CITED 

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/.

Tissot, B.N., Yoklavich, M.M., Love, M.S., York, K., and Amend, M., 2006, Benthic invertebrates that form habitat on deep banks off southern 

California, with special reference to deep sea coral: Fishery Bulletin, v. 104, p. 167–181.

Wentworth, C.K., 1922, A scale of grade and class terms for clastic sediments: Journal of Geology, v. 30, p. 377–392.

EXPLANATION

Substrate class

Fine- to medium-grained smooth sediment—Low backscatter, low rugosity; typically mud to medium-grained sand; often 

rippled and (or) burrowed

Mixed smooth sediment and rock—Moderate to very high backscatter, low rugosity; typically coarse-grained sand, gravel, 

cobbles, and bedrock

Medium- to coarse-grained sediment—Very high backscatter, low rugosity; typically medium- to coarse-grained sediment, with 

varying amounts of shell hash; in scour depressions

Rock and boulder, rugose—High backscatter, high rugosity; typically boulders and rugose bedrock

Location of real-time video observation and interpreted substrate class of seafloor

Fine- to medium-grained smooth sediment—Low backscatter, low rugosity; typically mud to medium-grained sand; often 

rippled and (or) burrowed

Mixed smooth sediment and rock—Moderate to very high backscatter, low rugosity; typically coarse-grained sand, gravel, 

cobbles, and bedrock

Medium- to coarse-grained sediment—Very high backscatter, low rugosity; typically medium- to coarse-grained sediment, with 

varying amounts of shell hash; in scour depressions

Rock and boulder, rugose—High backscatter, high rugosity; typically boulders and rugose bedrock

Location of digital still photograph and interpreted substrate class of seafloor

Fine- to medium-grained smooth sediment—Low backscatter, low rugosity; typically mud to medium-grained sand; often 

rippled and (or) burrowed

Mixed smooth sediment and rock—Moderate to very high backscatter, low rugosity; typically coarse-grained sand, gravel, 

cobbles, and bedrock

Medium- to coarse-grained sediment—Very high backscatter, low rugosity; typically medium- to coarse-grained sediment, with 

varying amounts of shell hash; in scour depressions

Rock and boulder, rugose—High backscatter, high rugosity; typically boulders and rugose bedrock

Interpreted substrate class depicted in digital still photograph—Indicated by colored frame around photograph (not shown on 

map; shown in figures only)

Fine- to medium-grained smooth sediment—Moderate to very high backscatter, low rugosity; typically coarse-grained sand, 

gravel, cobbles, and bedrock

Mixed smooth sediment and rock—Moderate to very high backscatter, low rugosity; typically coarse-grained sand, gravel, 

cobbles, and bedrock

Medium- to coarse-grained sediment—Very high backscatter, low rugosity; typically medium- to coarse-grained sediment, with 

varying amounts of shell hash; in scour depressions

Rock and boulder, rugose—High backscatter, high rugosity; typically boulders and rugose bedrock

Sample localities

From usSEABED (Reid and others, 2006)

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

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

1

U.S. Geological Survey;

2

National Oceanic and Atmospheric Administration, National Marine Fisheries Service

Ground-Truth Studies, Offshore of Pigeon Point Map Area, California

By

Nadine E. Golden,1 Guy R. Cochrane,1 and Lisa M. Krigsman2

2015

15 cm 3 Cam111_Tape56 Image 0175 -45m

Figure 5D. Digital still photograph no. E3 (see fig. 5A for location). Interface 

between rock outcrop and sand and shell hash (water depth, 45 m). Abiotic 

complexity is high, biotic complexity is present, and biocover is moderate. 

Biocover includes gorgonians (g) and cup coral (cc). Distance between lasers 

(green dots) is 15 cm.

g

cc

Figure 5C. Digital still photograph no. E2 (see fig. 5A for location). Interface 

between rock outcrop and sand and shell hash (water depth, 47 m). Abiotic 

complexity is high, biotic complexity is present, and biocover is moderate. 

Biocover includes gorgonians (g), cup coral (cc), and encrusting sponge (spo). 

Distance between lasers (green dots) is 15 cm.

2 Cam111_Tape56 Image 0156 -47m 15 cm

spo

g

cc

Figure 5B. Digital still photograph no. E1 (see fig. 5A for location). 

Unconsolidated fine sand (water depth, 46 m). Abiotic complexity is low, biotic 

complexity is present, and biocover is high. Biocover includes brittle stars (bs). 

Distance between lasers (green dots) is 15 cm.

15 cm 1 Cam111_Tape56 Image 0084 -46m

bs

E3 E1 E2

Box E

Figure 5A. Detailed view of seafloor character mapped south-southwest of Año Nuevo State 

Park, approximately 3 km offshore (see Box E, on map, for location), showing locations of 

periodic real-time video observations (dots) and digital still photographs (stars; see figs. 5B 

through 5D) from camera line CAM111, cruise C–02–12–SC.

7 Cam4_Tape7 Image 1454 -37m 15 cm

Figure 4H. Digital still photograph no. D7 (see fig. 4A for location). Rock outcrop 

(water depth, 37 m). Abiotic complexity is high, biotic complexity is present, and 

biocover is high. Biocover includes gorgonians (g), encrusting sponge (spo), and 

cup corals (cc). Distance between lasers (red dots) is 15 cm.

g

spo

cc

6 Cam4_Tape6 Image 1445 -38m 15 cm

Figure 4G. Digital still photograph no. D6 (see fig. 4A for location). Interface 

between rock outcrop and sand and shell hash (water depth, 38 m). Abiotic 

complexity is high biotic complexity is present, and biocover is moderate. 

Biocover include gorgonians (g); cup corals (cc); encrusting sponge (spo); 

fish-eating anemone, Urticina piscivora (sa); and a Ronquil, Rathbunella sp. (r). 

Distance between lasers (red dots) is 15 cm.

r

cc

sa g

5 Cam4_Tape6 Image 1437 -41m 15 cm

Figure 4F. Digital still photograph no. D5 (see fig. 4A for location). Rock outcrop 

(water depth, 41 m). Abiotic complexity is low, biotic complexity is present, and 

biocover is moderate. Biocover includes gorgonians (g) and cup corals (cc). 

Distance between lasers (red dots) is 15 cm.

g

cc

4 15 cm Cam4_Tape6 Image 1427 -44m

Figure 4E. Digital still photograph no. D4 (see fig. 4A for location). Rock outcrop 

(water depth, 44 m). Abiotic complexity is high, biotic complexity is present, and 

biocover is high. Biocover includes gorgonians (g), zoanthids (zoa), cup corals 

(cc), tubeworms (tw), encrusting sponge (spo), and sponges (spo). Distance 

between lasers (green dots) is 15 cm.

cc

g

spo

zoa

spo

tw

3 Cam4_Tape6 Image 1419 -44m 15 cm

Figure 4D. Digital still photograph no. D3 (see fig. 4A for location). Rock outcrop 

(water depth, 44 m). Abiotic complexity is high, biotic complexity is present, and 

biocover is high. Biocover includes sponge (spo), gorgonians (g), cup corals 

(cc), encrusting sponge (spo), and zoanthids (zoa). Distance between lasers 

(green dots) is 15 cm. 

cc

spo

spo

g

zoa

15 cm 2 Cam4_Tape6 Image 1415 -46m

Figure 4C. Digital still photograph no. D2 (see fig. 4A for location). Interface 

between rock outcrop and sand and shell hash (water depth, 46 m). Abiotic 

complexity is high, biotic complexity is present, and biocover is high. Biocover 

includes white plumed anemones, Metridium spp.(met); gorgonians (g); cup 

corals (cc); zoanthids (zoa); and encrusting sponge (spo). Distance between 

lasers (green dots) is 15 cm.

cc

g

spo

met

zoa

1 Cam4_Tape6 Image 1411 -46m 15 cm

Figure 4B. Digital still photograph no. D1 (see fig. 4A for location). Fine-grained 

sand with degraded ripples (water depth, 46 m). Abiotic complexity is low, biotic 

complexity is absent, and biocover is low. Biocover includes cup coral (cc). 

Distance between lasers (red dots) is 15 cm.

cc

D7

D6

D5

D4

D2

D3

D1

Box D Figure 4A. Detailed view of seafloor character mapped south-southwest of Año Nuevo 

State Park, approximately 3 km offshore (see Box D, on map, for location), showing 

locations of periodic real-time video observations (dots) and digital still photographs (stars; 

see figs. 4B through 4H) from camera line CAM4, cruise F–3–07–NC

spo

11 Cam5_Tape7 Image 1580 -26m 15 cm

Figure 3L. Digital still photograph no. C11 (see fig. 3A for location). Mixed boulders, 

cobbles, sand, and shell hash overlying rock (water depth, 26 m). Abiotic 

complexity is moderate, biotic complexity is present, and biocover is moderate. 

Biocover includes gorgonian (g); cup coral (cc); encrusting sponge (spo); and male 

kelp greenling, Hexagrammos decagrammus (kg). Distance between lasers (red 

dots are just out of view in this image but are visible in previous video frame) is 15 

cm.

cc

kg

g

spo spo

Cam5_Tape7 Image 1567 -27m 10 15 cm

Figure 3K. Digital still photograph no. C10 (see fig. 3A for location). 

Unconsolidated sand and shell hash with sharp crested ripples in bimodal 

pattern (water depth, 27 m). Abiotic complexity is low, biotic complexity is 

absent, and biocover is absent. Distance between lasers (red dots) is 15 cm.

Cam5_Tape7 Image 1538 -32m 9 15 cm

Figure 3J. Digital still photograph no. C9 (see fig. 3A for location). Rock outcrop 

with sand filled fracture (water depth, 32 m). Abiotic complexity is high, biotic 

complexity is absent, and biocover is high. Biocover includes encrusting 

sponge (spo), cup corals (cc), hydroids (h), and bryozoans (bry). Distance 

between lasers (green dots) is 15 cm.

spo

bry

cc

h

8 Cam5_Tape7 Image 1531 -35m 15 cm

Figure 3I. Digital still photograph no. C8 (see fig. 4A for location). 

Unconsolidated gravel (water depth, 35 m). Abiotic complexity is low, biotic 

complexity is absent, and biocover is absent. Distance between lasers (red 

dots) is 15 cm.

7 Cam5_Tape7 Image 1505 -37m 15 cm

Figure 3H. Digital still photograph no. C7 (see fig. 3A for location). Rock outcrop 

(water depth, 37 m). Abiotic complexity is high, biotic complexity is absent, and 

biocover is high. Biocover includes encrusting sponge (spo); cup corals (cc); 

vermillion star, Mediaster aequalis (vs); and female kelp greenling, 

Hexagrammos decagrammus (kg). Distance between lasers (green dots) is 15 

cm.

sst

cc

kg

spo

Cam5_Tape7 Image 1503 -38m 15 cm 6

Figure 3G. Digital still photograph no. C6 (see fig. 3A for location). Interface 

between rock outcrop and fine sand and mud (water depth, 38 m). Abiotic 

complexity is high, biotic complexity is absent, and biocover is high. Biocover 

includes bat star, Asterina miniata (bas); encrusting sponge (spo); cup coral (cc); 

blackeye goby, Rhinogobiops nicholsii (beg); and gopher rockfish, Sebastes 

carnatus (rf). Distance between lasers (green dots) is 15 cm.

bas

rf

beg

spo

cc

Cam5_Tape7 Image 1499 -39m 5 15 cm

Figure 3F. Digital still photograph no. C5 (see fig. 3A for location). Rock outcrop 

(water depth, 39 m). Abiotic complexity is moderate, biotic complexity is 

present, and biocover is high. Biocover includes gorgonians (g), cup corals (cc), 

and encrusting sponge (spo). Distance between lasers (red dots) is 15 cm.

spo

g cc

Cam5_Tape7 Image 1476 -44m 15 cm 4

Figure 3E. Digital still photograph no. C4 (see fig. 3A for location). Interface 

between rock outcrop and fine sand and mud (water depth, 44 m). Abiotic 

complexity is moderate, biotic complexity is present, and biocover is moderate. 

Biocover includes gorgonians (g), cup corals (cc), brittle stars (bs), and sponge 

(spo). Distance between lasers (red dots) is 15 cm.

spo

cc

bs

g

Cam5_Tape7 Image 1473 -45m 3 15 cm

Figure 3D. Digital still photograph no. C3 (see fig. 3A for location). Rock outcrop 

with sand filled fractures (water depth, 45 m). Abiotic complexity is moderate, 

biotic complexity is present, and biocover is moderate. Biocover includes sea 

anemone, Urticina spp., (sa); gorgonian (g); and cup corals (cc). Distance 

between lasers (red dots) is 15 cm.

sa

cc

g

15 cm 2 Cam5_Tape7 Image 1470 -46m

Figure 3C. Digital still photograph no. C2 (see fig. 3A for location). Rugose rock 

outcrop (water depth, 46 m). Abiotic complexity is high, biotic complexity is 

absent, and biocover is high. Biocover includes sponge (spo), zoanthids (zoa), 

tunicates (t), encrusting sponge (spo), and cup corals (cc). Distance between 

lasers (green dots) is 15 cm.

cc

spo

g

zoa

t

spo

1Cam5_Tape7 Image 1468 -46m 15 cm

Figure 3B. Digital still photograph no. C1 (see fig. 3A for location). Interface 

between rock outcrop and fine sand and mud (water depth, 46 m). Abiotic 

complexity is low, biotic complexity is present, and biocover is moderate. 

Biocover includes gorgonians (g), brittle stars (bs), cup corals (cc), sponge (spo), 

and driftweed (dw). Distance between lasers (red dots) is 15 cm.

g

dw

bs

spo

cc

Figure 3A. Detailed view of seafloor character mapped southwest of Año 

Nuevo State Park, approximately 2 km offshore (see Box C, on map, for 

location), showing locations of periodic real-time video observations (dots) 

and digital still photographs (stars; see figs. 3B through 3L) from camera line 

CAM5, cruise F–3–07–NC.

C11

C10

C9 C8

C7 C6

C5

C4

C3

C2

C1

Box C

15 cm 4 Cam6_Tape8 Image 1384 -19m

Figure 2E. Digital still photograph no. B4 (see fig. 2A for location). 

Unconsolidated fine-grained sand with sharp-crested ripples in a confused 

pattern (water depth, 19 m). Abiotic complexity is low, biotic complexity is 

absent, and biocover is low. Biocover includes drift weed (dw). Distance 

between lasers (green dots) is 15 cm.

dw

15 cm Cam6_Tape8 Image 1388 -23m

Figure 2D. Digital still photograph no. B3 (see fig. 2A for location). Rugose rock 

outcrop (water depth, 23 m). Abiotic complexity is high, biotic complexity is 

absent, and biocover is high. Biocover includes algae (a); cup corals (cc); 

strawberry anemones, Corynactis californica (sta); and encrusting sponge 

(spo). Distance between lasers (green dots are just out of view in this image but 

are visible in previous video frame) is 15 cm.

3

sta

spo

cc

a

2 Cam6_Tape8 Image 1377 -21m 15 cm

Figure 2C. Digital still photograph no. B2 (see fig. 2A for location). Mixed 

boulders, cobbles, gravel, sand, and shell hash (water depth, 21 m). Abiotic 

complexity is low, biotic complexity is absent, and biocover is low. Biocover 

includes bat star (bas) and cup coral (cc). Distance between lasers (green dots) 

is 15 cm.

cc

bas

Figure 2B. Digital still photograph no. B1 (see fig. 2A for location). Rock outcrop 

and cobbles (water depth, 21 m). Abiotic complexity is moderate, biotic 

complexity is absent, and biocover is moderate. Biocover includes sculpin (slp), 

encrusting sponge (spo), and cup coral (cc). Distance between lasers (green 

dots) is 15 cm.

1 Cam6_Tape8 Image 1367 -21m 15 cm

cc

spo

slp

Figure 2A. Detailed view of seafloor character mapped southeast of Pigeon Point, 

approximately 1.7 km offshore (see Box B, on map, for location), showing locations of periodic 

real-time video observations (dots) and digital still photographs (stars; see figs. 2B through 2E) 

from camera line CAM6, cruise F–3–07–NC.

B4

B3

B2

B1

Box B

15 cm 2 Cam8_Tape10 Image1502 -52m

Figure 1C. Digital still photograph no. A2 (see fig. 1A for location). 

Unconsolidated fine-grained sand and mud with degraded ripples (water depth, 

52 m). Abiotic complexity is low, biotic complexity is absent, and biocover is 

low. Biocover includes sea pen (sp). Distance between lasers (red dots) is 15 

cm. 

sp

15 cm 1Cam8_Tape10 Image1472 -56m

Figure 1B. Digital still photograph no. A1 (see fig. 1A for location). 

Unconsolidated fine-grained sand and mud with degraded ripples (water depth, 

56 m). Abiotic complexity is low, biotic complexity is absent, and biocover is 

low. Distance between lasers (red dots) is 15 cm.

Figure 1A. Detailed view of seafloor character mapped northwest of Pigeon Point, 

approximately 4 km offshore (see Box A, on map, for location), showing locations of 

periodic real-time video observations (dots) and digital still photographs (stars; see 

figs. 1B, 1C) from camera line CAM8, cruise F–3–07–NC.

A2

A1

Box A

ONE MILE = 0.869 NAUTICAL MILES

1 0.5 0 1 KILOMETER

7000 3500 0 7000 FEET

2 1 0 2 MILES

SCALE 1:50 000

APPROXIMATE MEAN

DECLINATION, 2015

MAGNETIC NORTH

13 / ° 1 2

TRUE NORTH

Seafloor-character map simplified from map on sheet 5, this 

report. Video observations recorded and digital still 

photographs taken in 2007–2012. Sample localities from 

usSEABED (Reid and others, 2006)

GIS database and digital cartography by Nadine E. Golden

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

E D

C

B

A

122°25' 122°20'

37°10'

37°05'

122°25' 122°20'

37°10'

37°05'

Año Nuevo 

State Park

Pigeon Point

U.S. Department of the Interior

U.S. Geological Survey

Open-File Report 2015–1232

Sheet 6 of 10

Pamphlet accompanies map