U.S. DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

National Marine Fisheries Service

Southwest Fisheries Science Center

NOAA-TM-NMFS-SWFSC-578

NOAA Technical Memorandum NMFS

MAY 2017

doi:10.7289/V5/TM-SWFSC-578

DISTRIBUTION OF CALIFORNIA SEA LIONS, NORTHERN 

ELEPHANT SEALS, PACIFIC HARBOR SEALS, AND 

STELLER SEA LIONS AT THE CHANNEL ISLANDS 

DURING JULY 2011-2015

Mark S. Lowry, Stephanie E. Nehasil, and Elizabeth M. Jaime
The National Oceanic and Atmospheric Administration (NOAA), organized in 1970, has 

evolved into an agency that establishes national policies and manages and conserves 

our oceanic, coastal, and atmospheric resources. An organizational element within 

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National Marine Fisheries Service (NMFS).

In addition to its formal publications, NMFS uses the NOAA Technical Memorandum 

series to issue informal scientific and technical publications when complete formal 

review and editorial processing are not appropriate or feasible. Documents within this 

series, however, reflect sound professional work and may be referenced in the formal 

scientific and technical literature.

SWFSC Technical Memorandums are accessible online at the SWFSC web site 

(http//swfsc.noaa.gov). Print copies are available from the National Technical 

Information Service, 5285 Port Royal Road, Springfield, VA 22151 (http://www.ntis.gov).
NOAA-TM-NMFS-SWFSC-578

U.S. DEPARTMENT OF COMMERCE

Wilbur L. Ross, Secretary of Commerce

National Oceanic and Atmospheric Administration

Benjamin Friedman, Acting NOAA Administrator

National Marine Fisheries Service

Samuel D. Rauch III, Acting Assistant Administrator for Fisheries

NOAA Technical Memorandum NMFS T 

This TM series is used for documentation and timely communication of preliminary results, interim reports, or special 

purpose information. The TMs have not received complete formal review, editorial control, or detailed editing 

doi:10.7289/V5/TM-SWFSC-578

MAY 2017

DISTRIBUTION OF CALIFORNIA SEA LIONS, NORTHERN 

ELEPHANT SEALS, PACIFIC HARBOR SEALS, AND 

STELLER SEA LIONS AT THE CHANNEL ISLANDS 

DURING JULY 2011-2015

1Marine Mammal and Turtle Division

Southwest Fisheries Science Center

National Marine Fisheries Service

National Oceanic and Atmospheric Administration

8901 La Jolla Shores Drive

La Jolla, CA 92037-1509, USA

Mark S. Lowry1, Stephanie E. Nehasil2, and Elizabeth M. Jaime2

2Ocean Associates, Inc.

Under contract to Marine Mammal & Turtle Division

Southwest Fisheries Science Center

National Marine Fisheries Service

National Oceanic and Atmospheric Administration

 8901 La Jolla Shores Drive

La Jolla, CA 92037-1509, USA
1

ABSTRACT

Aerial photographic surveys targeting California sea lions conducted during July 2011-

2015 were used to describe inter-island and intra-island distributions of California sea lions, 

northern elephant seals, Pacific harbor seals, and Steller sea lions within the Channel Islands. 

Age/sex class counts were made for California sea lions, Steller sea lions, and northern elephant 

seals, but not for Pacific harbor seals. Each island was subdivided into areas to document intraisland distribution of each species. California sea lions were found at all of the Channel Islands.

However, San Miguel Island, San Nicolas Island, Santa Barbara Island, and San Clemente Island 

accounted for 99.8% to 99.9% of California sea lion pups counted, with San Miguel Island and 

San Nicolas Island having the most pups and non-pups of those four islands. In July 2015, when 

all islands were surveyed for elephant seals, 2790 elephant seals (61.3% of Channel Islands 

total) were at San Miguel Island, 932 (20.5% of total) at San Nicolas Island, and 816 (17.9% of 

total) at Santa Rosa Island. There were 1367 Pacific harbor seals counted at the Channel Islands

in July 2015, and a single Steller sea lion was counted at San Nicolas Island in 2013.

INTRODUCTION

The Channel Islands, located in the Southern California Bight, (SCB; Figure 1), are 

inhabited by large populations of pinnipeds. California sea lions (Zalophus californianus), 

northern elephant seals (Mirounga angustirostris), and Pacific harbor seals (Phoca vitulina 

richardsi) are the most numerous pinniped species at the Channel Islands (Lowry et al., 2008;

Lowry et al., 2014; Lowry et al., 2017). California sea lions and Pacific harbor seals are found at 

all of the Channel Islands (Lowry et al., 2008; Lowry et al., 2014; Lowry et al., 2017). Northern 

fur seals (Callorhinus ursinus) have only been observed at a single island, and Steller sea lions 

(Eumetopias jubatus) and Guadalupe fur seals (Arctocephalus townsendi) are rare visitors to the 

Channel Islands (Bonnell et al., 1980; Stewart and Yochem, 1984; Orr, et al., 2012). 

Within the SCB, eight of the twelve Channel Islands are located in the U.S., and a group 

of four islands, known as Islas Coronados, are located in Mexico (Figure 1). Only the islands 

located in the U.S. will be discussed here. The eight islands in the U.S. are Anacapa Island (AI), 

Santa Cruz Island (SCruzI), Santa Rosa Island (SRI), San Miguel Island (SMI), Santa Barbara 

Island (SBI), San Nicolas Island (SNI), Santa Catalina Island (SCatI), and San Clemente Island 
2

(SCI). Three islets that have pinnipeds are Castle Rock (located 1 km from the NW shoreline of

SMI), Richardson Rock (located 10 km NW from Point Bennett, SMI), and Gull Island (located 

1.4 km from Punta Arena, SCruzI). SMI and SNI have the largest number of pinnipeds of all the 

Channel Islands (Bonnell et al., 1980; Lowry, 2002; Lowry et al., 2014; Lowry et al., 2017).

Various government agencies and private organizations are responsible for managing 

resources and activities at each of the Channel Islands. The U.S. Navy manages the island and 

surrounding waters of SNI and SCI. Channel Islands National Park manages AI, SCruzI (the 

National Park Service owns 24% of the island), SRI, SMI, and SBI. The Nature Conservancy 

also manages SCruzI (it owns 76% of the island). Channel Islands National Marine Sanctuary 

manages the surrounding waters from the mean high tide mark to six nautical miles offshore of 

AI, SCruzI, SRI, SMI, and SBI. SCatI is managed by the Catalina Island Conservancy. These

agencies and organizations require island pinniped distribution data to manage activities that 

could impact pinnipeds within their respective jurisdictions.

Since 1927, pinniped surveys conducted at the Channel Islands, most of which took place 

during summer, documented pinniped inter-island distribution (for a list refer to Lowry et al., 

2017), but very few documented intra-island distribution (Bartholomew, 1951; Bartholomew et 

al., 1951; Odell, 1972; Bonnell et al., 1980; Stewart and Yochem, 1984; Carretta et al., 2000; and 

Lowry, 2002). The most thorough intra-island study of pinniped distribution at the Channel 

Islands included 24 surveys during 1975-1977 (Bonnell et al., 1980). Since then, smaller-scale 

intra-island pinniped distribution studies have been published for some or all of the Channel 

Islands: (1) California sea lion and northern elephant seal pups at SNI during 1980-1982 (Stewart 

and Yochem, 1984), (2) all pinnipeds at SCI during 1998-1999 (Carretta et al., 2000), and (3) 

northern elephant seals at the Channel Islands during 1981-2001 (Lowry et al., 2002). 

Unfortunately, descriptions of intra-island pinniped distribution from these studies are currently 

obsolete due to expanding populations of California sea lions, northern elephant seals, and 

Pacific harbor seals that took place after those studies were published (Lowry et al., 2008, 2014; 

and Lowry et al., 2017). Inter-island distribution of California sea lions, northern elephant seal

pups, and Pacific harbor seals were described recently, but only for each annual peak abundance

period (Lowry et al., 2008, 2014; and Lowry et al., 2017). Peak abundance for northern elephant 

seals is during January and February (breeding season), California sea lions is during June and 
3

July (breeding season), and harbor seals is during late-May to early-June (molt season in 

southern California).

In 1987, the Southwest Fisheries Science Center (SWFSC) began using aerial 

photography at the Channel Islands to census pinnipeds. July aerial surveys began at SMI in 

1987, then expanded to include additional islands, until 2003 when all the Channel Islands were 

included in aerial surveys (Lowry et al., 1996; Lowry, 2002; Lowry and Carretta, 2003; Lowry et 

al, 2005 and 2008; Lowry et al., 2017). July surveys were intended to census California sea lions 

after all pups had been born because pup counts were used to monitor population trends and 

abundance of the U.S. population (e.g., Lowry and Maravilla-Chavez, 2005; Carretta et al., 

2015). Prior to 2011, only sea lions were counted during July surveys. However, starting in 

2011, elephant seals and harbor seals were also counted at SNI to document intra-island 

distribution of those species during summer for the U.S. Navy at SNI. Beginning in 2012,

northern elephant seals and Pacific harbor seals were counted from photographs at SMI, SBI, and 

SCI, and in 2015 all of the Channel Islands were included in the study. Population trends and 

abundance of elephant seals and harbor seals are determined using census data collected during 

winter (Lowry et al., 2002 and 2014) and at the end of May or early-June, respectively, (Lowry 

and Carretta, 2003; Lowry et al., 2005 and 2008); therefore the July surveys for these species 

only provide summer residence count-data.

Here we report the distribution of California sea lions, northern elephant seals, Pacific 

harbor seals, and Steller sea lions hauled out at the Channel Islands from aerial photographic 

surveys conducted by SWFSC during July 2011-2015. Total numbers of California sea lions, 

northern elephant seals, Pacific harbor seals, and Steller sea lions at the Channel Islands in July 

2011-2015 are provided, along with data showing inter-island and intra-island distributions of 

various age/sex classes and category totals of California sea lions, northern elephant seals, and 

Steller sea lions, as well as non-age/sex class counts of Pacific harbor seals.

METHODS

SWFSC Surveys

Aerial photographic surveys at all Channel Islands were conducted during early to midJuly 2011-2015 (Table 1). California sea lions and Steller sea lions were photographed at all 
4

islands during 2011-2015. Northern elephant seals and Pacific harbor seals were photographed 

at SNI during 2011-2014, at SMI and SBI during 2012-2014, and at all Channel Islands in 2015

(Table 2). Pinniped counts for Castle Rock were included in counts of SMI and counts for Gull 

Island were included in counts of SCruzI, but counts for Richardson Rock are reported 

separately.

SWFSC Survey methods

Aerial photographic surveys were conducted with a twin-engine, high-winged Partenavia 

P-68 Observer model aircraft (Figure 2). The glass nose of the Partenavia P-68 Observer model 

aircraft provided the pilot with excellent forward and downward views for aligning the aircraft 

over beaches and rocks. The aircraft was flown at a ground speed of 185 km/h (100 knots) and 

244 m (800 ft) altitude for most islands, except at SBI and the north side of West AI where the 

aircraft was flown at 396 m (1300 ft) altitude. The low altitude and lens configuration ensured 

that California sea lions could be detected on rocky substrates (especially when animals were wet 

and consequently darkly colored), aided in identification of different pinniped species and 

age/sex classes, and enabled accurate counts from aerial photographs. The aircraft was flown 

directly over the coastline with minor adjustments to locate and photograph pinnipeds onshore. 

Multiple overlapping photographic passes were made over large rocks and portions of island 

coastlines and beaches to ensure that all hauled-out pinnipeds were photographed. Surveys were 

conducted without regard to tidal conditions and at any time of day between approximately 2 

hours after sunrise and 2 hours before sunset.

During 2011-2013, pinnipeds were photographed with a Canon EOS 1Ds Mark III, fullframe 21.1-megapixel digital single lens reflex (DSLR) camera. In 2014 and 2015, they were 

photographed with a Canon EOS 5D Mark III, full-frame 22.3-megapixel DSLR. A Zeiss 85-

mm-focal-length lens was used at 244 m altitude during 2011-2014. A Canon 135-mm-focallength lens was used during 2011-2013, and a Zeiss 135-mm-focal-length lens was used in 2014

and 2015 to photograph pinnipeds from 396 m altitude. Image motion compensation was 

achieved by using a custom-made rocking mechanism in the camera mount manufactured by 

Aerial Imaging Solutions1. The focus ring of the 85mm lens was immobilized with tape when 

 

1 Aerial Imaging Solutions, LLC, 5 Myrica Way, Old Lyme, CT 06371. 

info@aerialimagingsolutions.com
5

focused at 244 m, and the 135 mm lens was taped when focused at 396 m. A laptop computer 

was connected to the camera, along with a GPS receiver and radar altimeter, and software in the 

computer (developed by Aerial Imaging Solutions) controlled the camera’s forward motion 

compensation mechanism and fired the camera on command. A video camera and monitor 

provided a view through the camera’s viewfinder, which allowed the operator to see what was 

being photographed. For each photograph, the computer recorded the geographical position, 

date, and time the photograph was taken in a comma separated values (csv) file. 

The DSLR camera was attached to a gimbal camera-mount that faced the camera 

vertically downward over a camera port inside the aircraft, and the camera was manually leveled 

at the vertical position with a bubble level. The computer controlled all camera functions. 

Camera aperture was set at f/5.6 in aperture priority shooting mode and shutter speed was set at 

or above 1/800 second by changing the ISO image sensor setting between 100 and 1000. 

Photographs were overexposed by +1/3 f-stop (for sunny conditions) or +2/3 f-stop (for overcast 

conditions). White balance in the camera was set on automatic, and all photographs were taken 

in JPEG image file format set at fine image quality and a 3:2 aspect ratio. The camera was 

operated at a cycle rate that achieved 40% overlap between adjacent photographs, and 

occasionally 60% overlap for short photographic passes. 

Adobe Bridge CS5 was used to review and select digital photographs, and to initiate the 

photo-merging process. Adobe Photoshop CS5 Extended, version 12.1 x64 on Windows 7 64-bit 

operating system, received photographs from Adobe Bridge CS5 and was subsequently used to 

create photographic mosaics from multiple overlapping digital photographs of beach- and rocksections within the Adobe Photoshop software screen on a 24-inch or 27-inch Dell ultra-sharp 

computer monitor. Photographs were merged manually using the move and transpose tools. 

Under-exposed or over-exposed images were brightened or darkened, respectively, with image 

tools in Adobe Photoshop. The brush tool was used to draw a line to separate and mark animals 

and to code areas on the mosaic that would be counted. Adjacent mosaic files of photographs 

were compared, and a brush-line was inserted onto the mosaic to separate counted animals from 

uncounted ones, and to demarcate areas where animals should or should not be counted. As 

age/sex class categories were manually counted using the count tool in Adobe Photoshop 

Extended, each animal was automatically marked with a unique colored dot and number. The 

software maintained a running total of each age/sex class category. The total counted for each 
6

age/sex class category would then be recorded into a Microsoft Excel spreadsheet along with 

other data identifying the counts (e.g., island, date, area codes, and mosaic file name), then 

transferred into a Microsoft Access database.

Species identification

Identification of pinniped species from aerial photographs begins with differentiating otariids

and phocids by locating the position of the fore flipper. The fore flipper is approximately just 

forward of the midway point on the body in otariids, and near the head in phocids. California sea 

lions, Steller sea lions, northern fur seals, and Guadalupe fur seals are otariids. Northern 

elephant seals and Pacific harbor seals are phocids. Although not all species found at the 

Channel Islands were counted in this study, the counter must be capable of identifying all 

pinniped species in the aerial photographs to prevent miscounts. The following characteristics 

were used to identify each of the six pinniped species found in aerial photographs of the Channel 

Islands:

California sea lion:

 Adult females are blond, brown, or grey; males are brown or grey

 Long square-like muzzle on narrow head

 Hair on top of fore flipper

 Sub-adult and adult males have a distinct sagittal crest

 Pups are brown or tan (black when wet) with a noticeable neck, and larger than 

northern fur seal pups

 Short hind flipper

 Fore flipper not as wide as in Steller sea lions

Steller sea lion:

 Massive size

 Adults are blond; juveniles and pups are brown

 Very broad head, with short muzzle

 Fore flipper is very wide, especially in adults

 Sub-adult and adult males do not have a sagittal crest

 Short hind flipper
7

Northern fur seal:

 Very long hind flippers that can reach up to the fore flipper; one hind flipper is often 

raised vertical when resting

 No hair on top of fore flipper; distinct pelage line visible where fore flipper meets the 

body

 Pups are black with short neck

 Adults are dark brown or black; some have light-dark patterns from outer guard-hair 

loss

 Pointed head

Guadalupe fur seal:

 Very long pointed head and muzzle

 Hair on top of fore flipper

 Grey color

 Hind flipper longer than California sea lion, but shorter than northern fur seal

Northern elephant seal:

 Uniform grey or brown color

 Become very large

 Juvenile, young-male, and sub-adult male elephant seals have a pointed muzzle when 

viewed from above

 Sub-adult males and adult males have a proboscis

 Adult males have a chest-shield of thick skin, and rounded head when viewed from 

above

 Hind flippers are longer and wider than those of harbor seals

Pacific harbor seal:

 Spotted or mottled with white or cream pelage mixed with black or brown spots

 Head has a square-shaped muzzle when viewed from above

 Small compared to elephant seals, up to the size of an adult female California sea lion

 Hind flippers are shorter and narrower than hind flippers of elephant seals
8

Counting categories

Although California sea lions were photographed and counted at all Channel Islands 

during July 2011-2015, northern elephant seals, Pacific harbor seals, and Steller sea lions were 

not photographed at all islands nor were they counted during the entire study period. Northern 

fur seals and Guadalupe fur seals were not counted because other researchers count them 

regularly at SMI where those species occur. Determination of age/sex class for Pacific harbor 

seals from aerial photographic imagery is unreliable and was not included. However, California 

sea lions, northern elephant seals, and Steller sea lions were counted by age/sex class. The 

following characteristics were used to identify age/sex classes of these three species from aerial 

photographs:

California sea lion:

 Live-pup: Newborns, very small compared to other age/sex classes, dark to light brown 

in color when dry, black when wet, with a short neck and muzzle

 Dead pup: Pups that are decomposing, bloated, or partially covered with sand, scavenged 

upon by western gulls (Larus occidentalis) or ravens (Corvus corax sinuatus), or that are 

lying on their side with the head bent back toward the spine as a result of rigor mortis

 Juvenile: Larger than live-pups, about one-fourth to two-thirds the length of an adult 

female with brown or light-brown hair, elongated neck and muzzle; sometimes found 

suckling on adult female or lying next to one; looks like a miniature adult female

 Adult female: Most often pelage will be blond in color when dry, but sometimes are 

brown; they are dark grey when wet; cranial sagittal crest is not present

 Young male: Approximately the same size as an adult female California sea lion; cranial 

crest has not begun to develop, and pelage is dark brown or blackish in color; during the 

breeding season, rarely found within groups of breeding adult females but will be found 

at the periphery of adult female groups or will be within groups of “bachelor” males or 

juveniles; when in tide pools they will often wrestle with similar-sized sea lions

 Sub-adult male: Sagittal crest is present and may or may not be fully formed, tuft of 

white hair on sagittal crest may or may not be present; pelage is dark brown to grey in 

color; they do not have a wide chest and neck

 Adult male: Sagittal crest is fully formed and has tuft of white hair; pelage is dark 

brown to grey in color; has a wide chest and neck; will often be patrolling a territory 
9

when in water or on land during the breeding season; when stationary or near vertical in 

the water, the tuft of white hair on the sagittal crest will be visible

Northern elephant seal:

 Live-pup: Normally none are present at Channel Islands during July; during breeding 

season they are black or silver-grey after their first molt; in springtime they become 

cream colored with a dark grey or brown back

 Juvenile: Approximately same size as an adult female or sub-adult male California sea 

lion, and often is cream or yellowish in color

 Adult female: Normally none are present at Channel Islands during July; they have a 

dark brown or grey color and slightly pointed head; penile opening is not present when 

laying on their back

 Young male: Same size as an adult female elephant seal, but smaller than sub-adult 

male; dark grey or brown pelage; penile opening is visible when laying on their back

 Sub-adult male: Larger than a young male or adult female elephant seal; proboscis not 

fully developed and pointed; does not have a chest shield, and is dark grey or brown in 

color; penile opening is visible when laying on their back

 Adult male: Very large elephant seal that has a very wide chest with a shield, and has a 

well-developed proboscis; dark grey or brown pelage; head has a rounded appearance

when viewed from above; penile opening is visible when laying on their back

Steller sea lion: 

 Pup: Two to three times longer than a California sea lion pup; dark brown pelage (black 

when wet)

 Juvenile: Broad head (not pointed like that of a California sea lion), and is same size as a 

sub-adult or adult male California sea lion, but without wide chest and sagittal crest; 

pelage is dark brown 

 Adult female: Two to three times larger than an adult male California sea lion; pelage is 

blond or yellowish, or grey when wet

 Young male: Approximately the same size as an adult female Steller sea lion; pelage is 

blond color, during breeding season will be alone at the periphery of adult female groups 

or will be within groups of “bachelor” males or juveniles, or alone on a rock 

 Sub-adult male: No development of wide chest and neck
10

 Adult male: Very wide chest and neck, and large broad head, they are blond in color, 

during the summer breeding season, adult males will defend a territory within or near 

groups of adult females, but sometimes will be found alone or with sub-adult males

Intra-island distribution

The perimeter of each island was divided into small area-coded units to describe intraisland distribution of California sea lions, northern elephant seals, Pacific harbor seals, and 

Steller sea lions. These area-code units either followed the Bureau of Land Management (BLM) 

numerical system in Bonnell et al. (1980) or new alphabetical codes that were created to divide 

or group the BLM codes (Figures 3 and 4). Additionally, area H at SMI, which includes Point 

Bennett, was further divided into numerical haulout sites (Figure 5) because of its highly dense

population of pinnipeds whose distribution varies within that area.

RESULTS

California sea lions

California sea lions were found at all Channel Islands (Tables 3 and 4). During July 

2011-2015, between 99,279 (in 2015) and 149,838 (in 2012) California sea lions were counted 

from digital aerial photographs taken at the Channel Islands (Table 3). The highest count of 

California sea lion pups at the Channel Islands was recorded in 2012 (n=67,124; Table 3). After 

that year, there was a reduction in pup counts at the Channel Islands in 2013 (n=42,686; 63.6% 

of 2012 total), in 2014 (n=47,691; 71.0% of 2012 total), and in 2015 (n=28,348; 42.2% of 2012 

total). During the 2011-2015 period, the highest number of adult female California sea lions was

counted in 2013 (n=60,733), and the highest number of adult males was counted in 2014 (n= 

7,453). California sea lion pups and adult females made up the highest number of California sea 

lions present at each of the Channel Islands during July 2011-2015 (Table 3).

During July 2011-2015, SMI had the largest number of California sea lions at the 

Channel Islands, followed by SNI, SBI, SCI and other islands (Tables 3 and 4). California sea 

lions at SMI averaged 62,150.2 individuals per year (SD = 7,836.8) and at SNI they averaged

52,634.8 individuals per year (SD = 9,899.0), followed by SBI and SCI (Table 4). California sea 

lion adult females made up the greatest proportion by age/sex class at all Channel Islands (Tables 
11

3 and 4). SMI, SNI, SBI, and SCI accounted for 99.8% to 99.9% of California sea lion pups 

counted at the Channel Islands, with SMI and SNI having the most pups of those four islands.

California sea lions were not uniformly distributed around the perimeter of each of the 

Channel Islands (Tables 5, 6, and 7; Figures 6, 7, and 8). Area H at SMI had more California sea 

lions on island (65.4% of pups, 41.6% of non-pups) than any other island-area at SMI (Table 7; 

Figures 6 and 8). Within area H at SMI, haulout site 54 had the most sea lions on island, with 

nearly twice as many as any other haulout site within Area H (Table 8). Area 406 at SCI had the 

most California sea lion pups and non-pups on island, 75.1% and 58.5% of the total counted, 

respectively (Table 7, Figures 6 and 8). Area A at SBI had the most sea lion pups and non-pups

on island, 75.2% and 47.7%, respectively. Areas D, H, L and Q at SNI had the most total 

number of California sea lions on island.

Northern elephant seals

Northern elephant seals were found on island mostly at SMI, SNI, and SRI, but a few (≤ 

11) were also found on island at SBI and SCI (Tables 3 and 4). In July 2015 (when all Channel 

Islands were surveyed for elephant seals), there were 4,554 northern elephant seals counted at the 

Channel Islands (Table 3). Northern elephant seal sub-adult males made up the highest number 

of elephant seals at the Channel Islands during July 2011-2015 (Table 3).

During July 2011-2015, SMI had the largest on island number of northern elephant seals

at the Channel Islands (Tables 3 and 4). In 2015, when all islands were surveyed for elephant 

seals, 2790 were on island at SMI (61.3% of Channel Islands total), 932 at SNI (20.5% of total), 

and 816 at SRI (17.9% of total). Sub-adult male elephant seals made up the greatest proportion 

by age/sex class at each of the Channel Islands where they were observed (Tables 3 and 4).

Northern elephant seals were not uniformly distributed around the perimeter of each of 

the Channel Islands (Tables 5, 6, and 7; Figures 9 and 10). Area H at SMI had more northern 

elephant seals on island (32.5% of island total) than any other island-area at SMI (Table 7). Area 

K at SNI had the most elephant seals on island. Elephant seals at SRI were mostly found in areas 

622D, 625A, and 626.
12

Pacific harbor seals

In July 2015 (when all Channel Islands were surveyed for harbor seals), Pacific harbor seals 

were found at all of the Channel Islands except SCatI and AI (Table 3). There were 1367 Pacific 

harbor seals counted at the Channel Islands in July 2015 (Table 3). SMI had the largest number 

of Pacific harbor seals of all the Channel Islands (Tables 3 and 4). In 2015 there were 550 

counted at SMI (40.2% of total), 259 counted at SNI (18.9%), 247 at SRI (18.1%), and the 

remaining (22.8%) were counted at other islands (Table 3).

Pacific harbor seals were not uniformly distributed around the perimeter of each of the 

Channel Islands (Tables 5, 6, and 7; Figures 11 and 12). Most Pacific harbor seals at SMI were 

found in areas J and N, and at SNI they were mostly found in areas L, N, and Q. Area 656 at 

SCI and areas 615A and 626 at SRI had the most harbor seals at each of those two islands (Table 

3, Figure 13).

Steller sea lions

A single juvenile Steller sea lion was counted within area H at SNI in 2013 (Table 3). 

DISCUSSION

California sea lions were the most abundant pinniped species hauled out at the Channel 

Islands during July 2011-2015 surveys. Although northern elephant seals were present also at 

the Channel Islands during those surveys, very few were hauled out compared to what is 

normally present during their winter breeding season. Pacific harbor seals were also less 

abundant than during their spring molt period (Lowry et al., 2008). Steller sea lions are rare 

visitors to the Channel Islands (M. Lowry, unpublished data) and only one was seen during this 

study at SNI in 2013.

The July 2011-2015 intra-island distribution was very different from pinniped intra-island 

distributions described in previous studies conducted since the late 1970s (Bonnell et al., 1980, 

and Stewart and Yochem 1984, M. Lowry, unpublished data). As populations of California sea 

lions and northern elephant seals grew, coastal occupation of the islands increased and spread 

around each of the main rookery-islands. At SNI, sea lions and elephant seals increased

eastward along the southern shoreline, eventually rounding the east end and occupying the 
13

northeastern side of the island. At SMI, sea lions increased along the northwestern shoreline 

from Point Bennett to Otter Harbor (Areas I and J), and on the southeastern and eastern end of 

the island (Areas A, B, and C).

The data collected during the July 2011-2015 surveys not only show inter-island and 

intra-island variability in the number of pinnipeds occupying the Channel Islands during summer 

months, but they also show annual variability in how pinnipeds occupy each island. Changing 

oceanographic conditions, as occurred during 2011-2015 (Peterson et al., 2015; Jacox et al., 

2016), influenced pinniped use of the Channel Islands. The only way to capture the effects of 

changing oceanographic effects on pinniped distribution is by conducting surveys spanning 

multiple years and seasons. For example, the SCB and California coast were affected by 

abnormally warm-water in 2014 (e.g., the warm-water “blob”) and by the 2015 El Niño (Bond et 

al., 2015; Peterson et al., 2015; Jacox et al., 2016). These warm-water conditions had an adverse 

effect on California sea lions resulting in decreased pup production and decreased abundance of 

non-pups at the Channel Islands, as shown from our study. At this time, it is unknown how these 

conditions affected northern elephant seals and Pacific harbor seals.

There is a need for multi-year surveys for other seasons at the Channel Islands to 

document how pinnipeds utilize island coastal areas during other seasonal or monthly time 

periods. As pinniped species shift from breeding to non-breeding activities on the islands, their 

abundance and distributions change. Knowing how pinniped abundance and distribution differs 

seasonally, monthly, and yearly is therefore beneficial for managing island use.

California sea lions are the most abundant pinniped species found at the Channel Islands 

during the peak of their breeding season in July. California sea lion pupping and breeding 

season begins in mid-May, peaks at the end of June or beginning of July, and ends by midAugust when most or all sub-adult males and adult males leave the Channel Island rookeries

(Allen et al., 2011). During the sea lion non-breeding season, the Channel Islands are mostly 

inhabited by adult females, pups, and juveniles, although there is a slight increase in the numbers 

of males in the winter, possibly due to the arrival of northward migrating males from the 

California sea lion population in Baja California, Mexico. 

Northern elephant seals are very abundant at the Channel Islands from December to 

March when their pupping and breeding season occurs, with the peak occurring during the end of 

January (Le Boeuf and Bonnell, 1980; Stewart, 1989). The largest elephant seal rookeries in the 
14

U. S. in 2010 were at SMI (16,208 pups), SNI (10,882 pups), and SRI (5,946 pups; Lowry et al. 

2014). It is during this period that elephant seals are censused for estimating population trends 

and abundance (Lowry et al., 2014). Another peak in elephant seal abundance occurs during 

their molting periods (Le Boeuf and Bonnell, 1980; Stewart, 1989). Adult females mostly molt 

in May and consequently were not present in large numbers in July. Adult and sub-adult males 

molt in July and so these age/sex classes represented the largest group of elephant seals in the 

July 2011-2015 surveys. 

At the Channel Islands, harbor seals are most abundant on land during their molting 

season, which peaks between mid-May and early-June (Stewart and Yochem, 1994). It is during 

this period that harbor seal surveys are conducted for estimating population trends and 

abundance. In summer, harbor seals do not haul out in great numbers at the Channel Islands. 

Lowry et al. (2003 and 2005) lists geographical positions (latitude and longitude) of haulout sites 

used by harbor seals at the Channel Islands during their molt period.

The data tables and figures in this report provide information that may be useful for 

managing human activities along the coastline of each of the Channel Islands during the summer 

season. Pinniped surveys conducted during additional seasons, including months during which 

northern elephant seals and Pacific harbor seals are most abundant on the islands, would provide 

necessary data for managing the islands during other times of the year.

ACKNOWLEDGEMENTS

Aerial photographic surveys of pinnipeds at the Channel Islands were supported by John 

Ugoretz (Marine Resources Manager, San Nicolas Island, NAVAIR Ranges Sustainability 

Office, U.S. Navy) and Martin Ruanne (Ecologist, NAVFAC, Naval Base Ventura County, U.S. 

Navy), who provided chartered aircraft and funds for counting the animals from digital aerial 

photographs. James Coler, Natural Resources Office, San Clemente Island, U.S. Navy 

coordinated with SCORE for overflight approval at San Clemente Island. This report was 

reviewed by Sharon Melin and Jeffrey Moore. All surveys were conducted under Marine 

Mammal Research Permit 14097 and National Marine Sanctuary Permit MULTI-2008-003.
15

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Barbara Island, California, in the 1950 breeding season. California Fish and Game

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Barbara Museum of Natural History.

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northern elephant seals (Mirounga angustirostris) from large-format aerial photographs 
17

taken at rookeries in southern California during the breeding season. U.S. Fishery 

Bulletin. 94:176-185.

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Bight: 1981-2001. NOAA Technical Memorandum NMFS NOAA-TM-NMFS-SWFSC345. 63p.

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California during May-July 2002. NOAA Technical Memorandum NMFS NOAA-TMNMFS-SWFSC-353. 48p.

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California, December 1-3, 2003 (pp. 485-497). National Park Service Technical 

Publication CHIS-05-01, Institute for Wildlife Studies, Arcata, California.

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richardsi, census in California during May - July 2004. Administrative Report LJ-05-06, 

available from Southwest Fisheries Science Center, 8604 La Jolla Shores Drive, La Jolla, 

CA 92037. 38 p.
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Lowry, M. S., J. V. Carretta and K. A. Forney. 2008. Pacific harbor seal census in California 

during May-July 2002 and 2004. California Fish and Game: 94:180-193.

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Reiter. 2014. Abundance, distribution, and population growth of the northern elephant 

seal (Mirounga angustirostris) in the United States from 1991-2010. Aquatic Mammals, 

40: 20-31. doi 10.1578/AM.40.1.2014.20.

Lowry, M. S., S. R. Melin, and J. L. Laake. 2017. Breeding season distribution and population 

growth of California sea lions, Zalophus californianus, in the United States during 1964-

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on San Nicolas Island, California. (Unpublished doctoral dissertation). University of 

California, Los Angeles.

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population at San Miguel Island, California during 2010 and 2011. Pp. 41-58, In: Testa, J. 

W. (ed.), Fur seal investigations, 2010-2011. U.S. Department of Commerce, NOAA 

Technical Memorandum NMFS-AFSC-241. 77 pp.
19

Perterson, W., M. Robert, and N. Bond. 2015. The warm blob – Conditions in the northeastern 

Pacific Ocean. PICES Press, 23:36-38.

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angustirostris Gill 1866, on the southern California Channel Islands. Ph. D. dissertation, 

University of California, Los Angeles.

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California, 1980-1982. Bulletin of the Southern California Academy of Sciences.

83:121-132.

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Bight. In W. L. Halvorson and G. J. Maender (editors), The Fourth California Islands 

Symposium: Update on the status of resources, p. 123-134. Santa Barbara Museum of 

Natural History, Santa Barbara, CA.
20

Table 1. Dates of aerial photographic surveys at the Channel Islands during 2011-2015.

Island/Rock 2011 2012 2013 2014 2015

Anacapa Island July 11 July 13 July 8 July 8 July 10

Richardson Rock July 13 July 14 Missed July 10 July 7

San Clemente Island July 11 July 13 July 13 July 07 July 12

San Miguel Island July 13 July 14 July 11 July 10 July 7

San Nicolas Island July 18 July 13 July 17 July 9 July 8

Santa Barbara Island July 18 July 13 July 11 July 8 July 9

Santa Catalina Island July 11 July 13 July 12 July 7 July 9

Santa Cruz Island July 11 July 13 July 8 July 8 July 9 & 10

Santa Rosa Island July 11 July 13 July 11 July 10 July 9 & 10
21

Table 2. Years in which California sea lions, northern elephant seals, and Pacific harbor seals 

were surveyed and counted at the Channel Islands during aerial photographic surveys conducted 

in July 2011-2015. NP = Not present when survey was conducted.

California sea lion Northern elephant seal Pacific harbor seal

Island Year Surveyed Counted Surveyed Counted Surveyed Counted

Anacapa Island 2011 Yes Yes No No

2012 Yes Yes No No

2013 Yes Yes No No

2014 Yes Yes No No

2015 Yes Yes Yes Yes Yes Yes

Richardson Rock 2011 Yes Yes Yes NP Yes NP

2012 Yes Yes Yes NP Yes NP

2013 No No No

2014 Yes Yes Yes NP Yes NP

2015 Yes Yes Yes NP Yes Yes

San Clemente Island 2011 Yes Yes Yes No Yes Yes

2012 Yes Yes Yes Yes Yes Yes

2013 Yes Yes Yes Yes Yes Yes

2014 Yes Yes Yes Yes Yes Yes

2015 Yes Yes Yes Yes Yes Yes

San Miguel Island 2011 Yes Yes No No

2012 Yes Yes Yes Yes Yes Yes

2013 Yes Yes Yes Yes Yes Yes

2014 Yes Yes Yes Yes Yes Yes

2015 Yes Yes Yes Yes Yes Yes

San Nicolas Island 2011 Yes Yes Yes Yes Yes Yes

2012 Yes Yes Yes Yes Yes Yes

2013 Yes Yes Yes Yes Yes Yes

2014 Yes Yes Yes Yes Yes Yes

2015 Yes Yes Yes Yes Yes Yes

Santa Barbara Island 2011 Yes Yes Yes Yes Yes Yes

2012 Yes Yes Yes Yes Yes Yes

2013 Yes Yes Yes Yes Yes Yes

2014 Yes Yes Yes Yes Yes Yes

2015 Yes Yes Yes Yes Yes Yes

Santa Catalina Island 2011 Yes Yes No No

2012 Yes Yes No No

2013 Yes Yes No No

2014 Yes Yes No No

2015 Yes Yes Yes NP Yes NP

Santa Cruz Island 2011 Yes Yes No No

2012 Yes Yes No No

2013 Yes Yes No No

2014 Yes Yes No No

2015 Yes Yes Yes NP Yes Yes
22

Table 2. (Continued)

California sea lion Northern elephant seal Pacific harbor seal

Island Year Surveyed Counted Surveyed Counted Surveyed Counted

Santa Rosa Island 2011 Yes Yes No No

2012 Yes Yes No No

2013 Yes Yes No No

2014 Yes Yes No No

2015 Yes Yes Yes Yes Yes Yes
23

Table 3. Counts of each age-sex class and category totals with the percentage represented by each island of the Channel Islands total 

for California sea lions, northern elephant seals, Pacific harbor seals, and Steller sea lions during aerial photographic surveys 

conducted in July 2011-2015.

Pups Juveniles

Adult

females

Young

males

Sub-adult

males

Adult

males

Non-pup

total Total

Year Island/Rock count % count % count % count % count % count % count % count %

California sea lion

2011 Anacapa Island 32 0.1 323 2.1 579 1.2 127 3.8 12 0.2 24 0.4 1,065 1.3 1,097 0.8

Richardson Rock 0 0.0 53 0.3 186 0.4 4 0.1 23 0.5 16 0.3 282 0.4 282 0.2

San Clemente Island 2,883 4.7 343 2.2 3,243 6.6 104 3.1 57 1.2 225 3.6 3,972 5.0 6,855 4.9

San Miguel Island 26,953 43.5 10,094 64.8 26,109 53.1 2,003 59.4 2,853 58.4 3,401 54.5 44,460 56.1 71,413 50.6

San Nicolas Island 28,087 45.4 3,629 23.3 15,191 30.9 924 27.4 1,755 35.9 2,316 37.1 23,815 30.1 51,902 36.8

Santa Barbara Island 3,941 6.4 359 2.3 2,414 4.9 165 4.9 134 2.7 244 3.9 3,316 4.2 7,257 5.1

Santa Catalina Island 17 0.0 118 0.8 251 0.5 22 0.7 2 0.0 6 0.1 399 0.5 416 0.3

Santa Cruz Island 1 0.0 285 1.8 683 1.4 16 0.5 38 0.8 3 0.0 1,025 1.3 1,026 0.7

Santa Rosa Island 0 0.0 365 2.3 515 1.0 6 0.2 9 0.2 5 0.1 900 1.1 900 0.6

Channel Islands total 61,914 100.0 15,569 100.0 49,171 100.0 3,371 100.0 4,883 100.0 6,240 100.0 79,234 100.0 141,148 100.0

2012 Anacapa Island 50 0.1 458 2.9 418 0.8 113 3.2 15 0.2 14 0.2 1,018 1.2 1,068 0.7

Richardson Rock 1 0.0 51 0.3 135 0.3 2 0.1 20 0.3 7 0.1 215 0.3 216 0.1

San Clemente Island 3,220 4.8 689 4.3 2,634 5.3 60 1.7 176 2.9 269 3.8 3,828 4.6 7,048 4.7

San Miguel Island 28,289 42.1 7,972 49.8 21,664 43.4 1,508 42.1 3,064 49.8 3,163 45.1 37,371 45.2 65,660 43.8

San Nicolas Island 31,972 47.6 5,317 33.2 20,171 40.4 1,527 42.7 2,612 42.4 3,251 46.4 32,878 39.7 64,850 43.3

Santa Barbara Island 3,558 5.3 452 2.8 2,862 5.7 221 6.2 208 3.4 271 3.9 4,014 4.9 7,572 5.1

Santa Catalina Island 31 0.0 74 0.5 147 0.3 6 0.2 4 0.1 7 0.1 238 0.3 269 0.2

Santa Cruz Island 0 0.0 402 2.5 1,078 2.2 56 1.6 20 0.3 15 0.2 1,571 1.9 1,571 1.0

Santa Rosa Island 3 0.0 609 3.8 835 1.7 87 2.4 38 0.6 12 0.2 1,581 1.9 1,584 1.1

Channel Islands total 67,124 100 16,024 100 49,944 100 3,580 100 6,157 100 7,009 100 82,714 100 149,838 100

20131 Anacapa Island 48 0.1 261 1.4 642 1.1 179 5.8 38 0.6 26 0.4 1,146 1.2 1,194 0.9

San Clemente Island 2,458 5.8 777 4.1 3,703 6.1 83 2.7 184 2.8 223 3.5 4,970 5.2 7,428 5.4

San Miguel Island 21,014 49.2 8,563 45.1 26,826 44.2 1,708 55.7 3,402 51.2 2,878 45.0 43,377 45.3 64,391 46.5

San Nicolas Island 16,225 38.0 8,037 42.4 24,277 40.0 956 31.2 2,688 40.4 2,881 45.0 38,839 40.5 55,063 39.8

Santa Barbara Island 2,918 6.8 615 3.2 3,495 5.8 100 3.3 258 3.9 351 5.5 4,819 5.0 7,737 5.6

Santa Catalina Island 20 0.0 109 0.6 294 0.5 5 0.2 10 0.2 8 0.1 426 0.4 446 0.3

Santa Cruz Island 0 0.0 450 2.4 935 1.5 31 1.0 34 0.5 19 0.3 1,469 1.5 1,469 1.1

Santa Rosa Island 3 0.0 155 0.8 561 0.9 5 0.2 32 0.5 15 0.2 768 0.8 771 0.6
24

Table 3. (Continued)

Pups Juveniles

Adult

females

Young

males

Sub-adult

males

Adult

males

Non-pup

total Total

Year Island/Rock count % count % count % count % count % count % count % count %

California sea lion (continued)

2013 Channel Islands total 42,686 100 18,967 100 60,733 100 3,067 100 6,646 100 6,401 100 95,814 100 138,499 100

2014 Anacapa Island 52 0.1 189 1.9 400 0.7 230 7.8 49 0.9 20 0.3 888 1.1 940 0.7

Richardson Rock 0 0.0 78 0.8 387 0.7 17 0.6 19 0.3 12 0.2 513 0.6 513 0.4

San Clemente Island 1,927 4.0 696 7.1 4,064 7.1 83 2.8 121 2.2 265 3.6 5,229 6.3 7,156 5.5

San Miguel Island 23,607 49.5 4,075 41.6 23,410 41.1 1,223 41.5 2,700 48.8 3,490 46.8 34,898 42.2 58,505 44.9

San Nicolas Island 19,587 41.1 4,205 42.9 23,363 41.0 1,082 36.8 2,446 44.2 3,350 44.9 34,446 41.7 54,033 41.4

Santa Barbara Island 2,498 5.2 296 3.0 3,785 6.6 111 3.8 153 2.8 284 3.8 4,629 5.6 7,127 5.5

Santa Catalina Island 19 0.0 36 0.4 247 0.4 24 0.8 3 0.1 12 0.2 322 0.4 341 0.3

Santa Cruz Island 0 0.0 119 1.2 650 1.1 56 1.9 32 0.6 13 0.2 870 1.1 870 0.7

Santa Rosa Island 1 0.0 109 1.1 651 1.1 118 4.0 12 0.2 7 0.1 897 1.1 898 0.7

Channel Islands total 47,691 100 9,803 100 56,957 100 2,944 100 5,535 100 7,453 100 82,692 100 130,383 100

2015 Anacapa Island 40 0.1 324 3.1 795 1.8 61 1.4 20 0.3 19 0.3 1219 1.7 1259 1.3

Richardson Rock 0 0.0 59 0.6 93 0.2 8 0.2 15 0.2 12 0.2 187 0.3 187 0.2

San Clemente Island 385 1.4 449 4.3 1,947 4.5 214 4.9 126 1.9 170 2.8 2,906 4.1 3291 3.3

San Miguel Island 17,084 60.3 4,733 45.0 20,746 48.0 1,705 38.7 3,442 52.0 3,072 50.3 33,698 47.5 50,782 51.2

San Nicolas Island 9,963 35.1 4,053 38.5 16,477 38.1 1,570 35.6 2,740 41.4 2,523 41.3 27,363 38.6 37,326 37.6

Santa Barbara Island 864 3.0 348 3.3 1,552 3.6 203 4.6 215 3.2 271 4.4 2,589 3.7 3,453 3.5

Santa Catalina Island 11 0.0 157 1.5 445 1.0 78 1.8 11 0.2 4 0.1 695 1.0 706 0.7

Santa Cruz Island 1 0.0 200 1.9 1098 2.5 335 7.6 27 0.4 14 0.2 1,674 2.4 1,675 1.7

Santa Rosa Island 0 0.0 197 1.9 92 0.2 237 5.4 25 0.4 17 0.3 568 0.8 568 0.6

Channel Islands total 28,348 100 10,521 100 43,245 100 4,411 100 6,621 100 6,102 100 70,899 100 99,247 100

Northern elephant seal

20112 San Nicolas Island 0 4 0 3 332 273 612 615

Santa Barbara Island 0 0 0 0 1 3 4 4

20122 San Clemente Island 0 0 0 1 4 2 7 7

San Miguel Island 0 20 0 129 1,388 395 1,932 1,932

San Nicolas Island 0 9 0 58 389 346 802 802

Santa Barbara Island 0 0 0 0 3 2 5 5

20132 San Clemente Island 0 0 0 0 0 0 0 0

San Miguel Island 0 66 0 303 1,364 305 2,038 2,038
25

Table 3. (Continued)

Pups Juveniles

Adult

females

Young

males

Sub-adult

males

Adult

males

Non-pup

total Total

Year Island/Rock count % count % count % count % count % count % count % count %

Northern elephant seal (Continued)

20132 San Nicolas Island 0 28 0 91 489 125 733 733

Santa Barbara Island 0 2 0 2 3 1 8 8

20142 San Clemente Island 0 0 0 1 3 2 6 6

San Miguel Island 0 11 0 421 1,248 958 2,638 2,638

San Nicolas Island 0 3 0 122 395 295 815 815

Santa Barbara Island 0 0 0 2 6 0 8 8

2015 San Clemente Island 0 0 0.0 0 2 0.3 2 0.1 1 0.2 5 0.1 5 0.1

San Miguel Island 0 21 72.4 0 434 58.3 1,976 62.6 359 57.4 2,790 61.3 2,790 61.3

San Nicolas Island 0 6 20.7 0 208 28.0 591 18.7 127 20.3 932 20.5 932 20.5

Santa Barbara Island 0 1 3.4 0 3 0.4 7 0.2 0 0.0 11 0.2 11 0.2

Santa Rosa Island 0 1 3.4 0 97 13.0 580 18.4 138 22.1 816 17.9 816 17.9

Channel Islands total 0 29 100 0 744 100 3,156 100 625 100 4,554 100 4,554 100

Pacific harbor seal

20112 San Nicolas Island 229

20122 San Miguel Island 559

San Nicolas Island 326

Santa Barbara Island 18

20132 San Miguel Island 565

San Nicolas Island 605

Santa Barbara Island 8

20142 San Clemente Island 16

San Miguel Island 673

San Nicolas Island 610

2015 Anacapa Island 2 0.1

Richardson Rock 3 0.2

San Clemente Island 116 8.5

San Miguel Island 550 40.2

San Nicolas Island 259 18.9

Santa Barbara Island 9 0.7

Santa Cruz Island 181 13.2
26

Table 3. (Continued)

Pups Juveniles

Adult

females

Young

males

Sub-adult

males

Adult

males

Non-pup

total Total

Year Island/Rock count % count % count % count % count % count % count % count %

Pacific harbor seal (Continued)

2015 Santa Rosa Island 247 18.1

Channel Islands total 1,367 100

Steller sea lion

2013 San Nicolas Island 0 1 100.0 0 0 0 0 1 100.0 1 100

Channel Islands total 0 1 0 0 0 0 1 1

1Richardson Rock was not photographed.

2Not all Channel Islands were censused for northern elephant seals and Pacific harbor seals, therefore cannot compute percentage of 

all Channel Islands.
27

Table 4. Mean and standard deviation (SD) of counts represented by each age/sex class and category total for California sea lions, 

northern elephant seals, and Steller sea lions counted from aerial photographs taken during surveys conducted in July 2011-2015. 

Note: n = number of years of data; blank = no data collected.

Pups Juveniles

Adult

females

Young

males

Sub-adult 

males

Adult

males

Non-pup

total Total

Island/Rock n Mean Std Mean Std Mean Std Mean Std Mean Std Mean Std Mean Std Mean Std

California sea lion

Anacapa

 Island

5 44.4 8.3 311.0 99.1 566.8 164.2 142.0 64.7 26.8 16.0 20.6 4.7 1,067.2 126.3 1,111.6 122.6

Richardson

 Rock

4 0.3 0.5 60.3 12.3 200.3 130.2 7.8 6.7 19.3 3.3 11.8 3.7 299.3 148.0 299.5 147.8

San Clemente

 Island

5 2,174.6 1,111.2 590.8 185.0 3,118.2 845.3 108.8 60.8 132.8 51.0 230.4 40.1 4,181.0 937.4 6,355.6 1,725.6

San Miguel

 Island

5 23,389.4 4,531.9 7,087.4 2,579.6 23,751.0 2,670.1 1,629.4 287.8 3,092.2 327.9 3,200.8 248.0 38,760.8 4,906.0 62,150.2 7,836.8

San Nicolas

 Island

5 21,166.8 8,903.4 5,048.2 1,783.3 19,895.8 4,034.7 1,211.8 313.4 2,448.2 403.1 2,864.2 448.0 31,468.2 5,928.9 52,634.8 9,899.0

Santa Barbara

 Island 5 2,755.8 1,195.8 414.2 125.5 2,821.6 889.0 160.0 53.8 193.6 50.0 284.2 40.1 3,873.4 928.1 6,629.2 1,792.1

Santa Catalina

 Island

5 19.6 7.3 98.8 45.9 276.8 108.4 27.0 29.8 6.0 4.2 7.4 3.0 416.0 172.3 435.6 166.1

Santa Cruz 

 Island

5 0.4 0.5 291.2 137.4 888.8 212.8 98.8 133.1 30.2 6.9 12.8 5.9 1,321.8 353.6 1,322.2 353.6

Santa Rosa

 Island

5 1.4 1.5 287.0 204.3 530.8 274.2 90.6 95.8 23.2 12.5 11.2 5.1 942.8 381.5 944.2 382.4

Northern elephant seal

San Clemente

 Island

4 0.0 0.0 0.0 0.0 0.0 0.0 1.0 0.8 2.3 1.7 1.3 1.0 4.5 3.1 4.5 3.1

San Miguel

 Island

4 0.0 0.0 29.5 24.7 0.0 0.0 321.8 141.4 1,494.0 327.1 504.3 304.8 2,349.5 427.6 2,349.5 427.6

San Nicolas

 Island

5 0.0 0.0 10.0 10.3 0.0 0.0 96.4 76.4 439.2 101.8 233.2 101.4 778.8 117.5 779.4 116.5

Santa Barbara

 Island

5 0.0 0.0 0.6 0.9 0.0 0.0 1.4 1.3 4.0 2.4 1.2 1.3 7.2 2.8 7.2 2.8

Santa Rosa

 Island

1 0.0 1.0 0.0 97.0 580.0 138.0 816.0 816.0
28

Table 4. (Continued)

Pups Juveniles

Adult

females

Young

males

Sub-adult 

males

Adult

males

Non-pup

total Total

Island/Rock n Mean Std Mean Std Mean Std Mean Std Mean Std Mean Std Mean Std Mean Std

Pacific harbor seal

Anacapa

 Island

1 2.0

Richardson

Rock

1 3.0

San Clemente

 Island

2 66.0 70.7

San Miguel

 Island

4 586.8 57.8

San Nicolas

 Island

5 405.8 187.5

Santa Barbara

 Island

3 11.7 5.5

Santa Cruz

 Island

1 181.0

Santa Rosa

 Island

1 247.0

Steller sea lion

San Nicolas

 Island

1 0.0 1.0 0.0 0.0 0.0 0.0 1.0 1.0
29

Table 5. Island-area counts by age-sex class and category total for California sea lions, northern 

elephant seals, and Pacific harbor seals from aerial photographs taken at the Channel Islands 

during July 2011-2015. Counts are provided only for island-areas having animals. Refer to 

Table 1 for survey date and to Figures 3 and 4 for location of island-areas.

Island Year Area

PupsJuvenilesAdult femalesYoung malesSub-adult malesAdult malesNon-pup totalTotal

California sea lion

Anacapa Island 2011 680 32 323 579 127 12 24 1,065 1,097

2012 680 50 458 418 113 15 14 1,018 1,068

2013 680 48 261 642 179 38 26 1,146 1,194

2014 680 52 189 400 230 49 20 888 940

2015 680 40 324 795 61 20 19 1,219 1,259

Richardson Rock1 2011 103 0 53 186 4 23 16 282 282

2012 103 1 51 135 2 20 7 215 216

2014 103 0 78 387 17 19 12 513 513

2015 103 0 59 93 8 15 12 187 187

San Clemente Island 2011 404 0 8 27 17 13 10 75 75

406 2,300 174 1,804 19 21 131 2,149 4,449

407 583 131 846 67 20 69 1,133 1,716

411 0 31 566 1 3 15 616 616

2012 406 2,521 288 1,644 12 48 157 2,149 4,670

407 671 135 620 48 118 99 1,020 1,691

410 0 25 6 0 0 0 31 31

411 28 241 364 0 10 13 628 656

2013 404 1 44 55 9 20 3 131 132

406 1,844 247 1,842 14 63 132 2,298 4,142

407 603 221 1,041 59 91 76 1,488 2,091

411 10 265 765 1 10 12 1,053 1,063

2014 404 1 43 30 15 13 7 108 109

406 1,416 363 2,061 16 47 153 2,640 4,056

407 493 156 1,224 45 54 92 1,571 2,064

411 17 134 749 7 7 13 910 927

2015 404 0 8 22 37 7 2 76 76

406 266 168 999 34 39 109 1,349 1,615

407 113 79 503 114 69 56 821 934

410 0 21 30 7 2 0 60 60

411 6 173 393 22 9 3 600 606

San Miguel Island 2011 A 24 4,341 1,896 154 228 77 6,696 6,720

B 0 0 1 0 4 1 6 6

C 376 1,652 2,521 28 58 50 4,309 4,685

D 0 0 1 0 0 4 5 5

E 0 0 0 2 23 23 48 48

F 0 0 1 184 454 787 1,426 1,426

G 3,133 164 2,072 68 17 145 2,466 5,599

H 17,986 1,279 13,788 749 827 1,431 18,074 36,060

I 0 1 0 160 316 418 895 895

J 4,477 1,075 4,372 656 920 362 7,385 11,862

K 0 0 0 0 0 0 0 0

L 7 1,468 478 2 6 16 1,970 1,977

M 0 0 0 0 0 0 0 0

N 0 0 0 0 0 0 0 0
30

Table 5. (Continued)

Island Year Area

PupsJuvenilesAdult femalesYoung malesSub-adult malesAdult malesNon-pup totalTotal

California sea lion (Continued)

San Miguel Island 2011 O 950 114 979 0 0 87 1,180 2,130

(Continued) 2012 A 9 1,853 1,108 53 204 72 3,290 3,299

B 0 0 0 0 7 6 13 13

C 429 740 2,003 72 70 45 2,930 3,359

D 0 0 0 0 0 6 6 6

E 0 0 0 7 25 26 58 58

F 0 10 12 131 595 731 1,479 1,479

G 3,216 358 2,083 75 34 141 2,691 5,907

H 19,277 2,363 11,633 565 751 1,162 16,474 35,751

I 0 7 17 97 382 435 938 938

J 4,535 1,283 3,460 421 948 443 6,555 11,090

L 4 1,287 623 87 47 32 2,076 2,080

N 0 0 0 0 0 1 1 1

O 819 71 725 0 1 63 860 1,679

2013 A 8 1,155 1,830 125 153 42 3,305 3,313

B 7 529 831 26 33 20 1,439 1,446

C 624 1,165 2,614 17 19 47 3,862 4,486

D 0 0 2 0 4 10 16 16

E 0 0 4 4 17 20 45 45

F 0 24 9 156 415 288 892 892

G 2,325 700 2,141 137 294 311 3,583 5,908

H 13,645 3,203 13,185 585 858 1,202 19,033 32,678

I 6 36 45 264 840 472 1,657 1,663

J 3,717 1,160 4,586 362 737 371 7,216 10,933

K 0 0 1 0 5 5 11 11

L 35 536 764 32 25 16 1,373 1,408

N 0 0 1 0 0 2 3 3

O 647 55 813 0 2 72 942 1,589

2014 A 15 865 1,368 204 191 65 2,693 2,708

B 22 390 1,518 30 43 25 2,006 2,028

C 763 235 2,034 32 41 67 2,409 3,172

D 0 0 1 1 14 26 42 42

E 0 0 2 3 15 33 53 53

F 3 8 23 50 304 424 809 812

G 2,616 152 1,737 52 217 269 2,427 5,043

H 14,922 1,108 10,127 387 655 1,351 13,628 28,550

I 25 28 118 230 708 687 1,771 1,796

J 4,622 719 4,317 224 482 406 6,148 10,770

K 0 0 1 0 2 15 18 18

L 62 525 1,398 2 20 21 1,966 2,028

M 0 0 0 3 3 8 14 14

N 0 3 7 4 4 4 22 22

O 557 42 759 1 1 89 892 1,449

2015 A 8 793 793 219 216 62 2,083 2,091

B 22 962 1,637 76 27 25 2,727 2,749

C 546 352 1,672 40 42 70 2,176 2,722

D 0 0 0 1 13 13 27 27

E 0 1 0 4 22 31 58 58
31

Table 5. (Continued)

Island Year Area

PupsJuvenilesAdult femalesYoung malesSub-adult malesAdult malesNon-pup totalTotal

California sea lion (Continued)

San Miguel Island 2015 F 6 21 23 45 299 376 764 770

(Continued) G 1,819 141 1,437 82 204 265 2,129 3,948

H 10,972 842 10,070 484 950 1,220 13,566 24,538

I 80 40 306 304 924 509 2,083 2,163

J 3,090 1,009 3,687 361 704 406 6,167 9,257

K 0 0 0 0 4 6 10 10

L 60 526 556 85 29 18 1,214 1,274

M 0 0 0 0 1 0 1 1

N 0 3 2 2 3 3 13 13

O 481 43 563 2 4 68 680 1,161

San Nicolas Island 2011 A 192 632 525 10 15 15 1,197 1,389

B 552 66 472 0 2 23 563 1,115

C 770 22 305 41 174 166 708 1,478

D 4,927 241 2,064 15 9 153 2,482 7,409

E 998 251 659 159 216 160 1,445 2,443

F 2,989 219 1,371 15 11 136 1,752 4,741

G 303 90 191 119 222 144 766 1,069

H 5,085 259 2,284 76 67 295 2,981 8,066

I 1,527 137 576 78 113 141 1,045 2,572

J 3,344 248 1,946 63 132 242 2,631 5,975

K 0 1 0 17 93 178 289 289

L 5,388 337 2,728 56 67 267 3,455 8,843

M 1,955 137 1,138 50 241 243 1,809 3,764

N 0 0 0 0 0 6 6 6

Q 57 989 932 225 393 147 2,686 2,743

2012 A 285 237 941 80 101 32 1,391 1,676

B 686 96 547 7 6 40 696 1,382

C 720 35 274 76 189 245 819 1,539

D 5,894 250 2,304 2 9 201 2,766 8,660

E 1,245 176 873 154 258 227 1,688 2,933

F 3,613 220 1,589 47 29 203 2,088 5,701

G 385 84 255 175 328 242 1,084 1,469

H 5,800 426 2,347 120 111 386 3,390 9,190

I 1,788 205 730 137 200 193 1,465 3,253

J 3,709 473 2,257 162 206 274 3,372 7,081

K 0 2 4 31 209 223 469 469

L 5,933 587 3,923 126 176 373 5,185 11,118

M 1,854 268 1,726 150 236 326 2,706 4,560

Q 60 2,258 2,401 260 554 286 5,759 5,819

2013 A 114 537 1,129 12 64 20 1,762 1,876

B 459 156 525 5 4 30 720 1,179

C 609 235 591 92 322 235 1,475 2,084

D 3,005 835 2,301 5 26 160 3,327 6,332

E 564 340 854 93 251 199 1,737 2,301

F 1,679 581 1,576 0 19 193 2,369 4,048

G 121 194 327 66 336 284 1,207 1,328

H 2,466 813 2,262 29 91 339 3,534 6,000

I 825 489 706 73 196 154 1,618 2,443
32

Table 5. (Continued)

Island Year Area

PupsJuvenilesAdult femalesYoung malesSub-adult malesAdult malesNon-pup totalTotal

California sea lion (Continued)

San Nicolas Island 2013 J 1,853 809 2,481 48 130 237 3,705 5,557

(Continued) K 0 2 3 80 194 126 405 405

L 3,333 879 3,713 39 135 330 5,096 8,429

M 1,136 357 2,119 69 308 296 3,149 4,285

N 0 0 0 0 0 1 1 1

Q 61 1,810 5,690 345 612 277 8,734 8,795

2014 A 125 370 415 163 47 20 1,015 1,140

B 490 138 743 9 2 36 928 1,418

C 592 191 476 125 234 239 1,265 1,857

D 3,177 310 2,442 21 9 191 2,973 6,150

E 639 399 934 101 261 221 1,916 2,555

F 2,025 364 1,857 18 25 206 2,470 4,495

G 143 187 295 153 289 293 1,217 1,360

H 3,189 406 2,551 56 98 342 3,453 6,642

I 886 179 694 77 182 202 1,334 2,220

J 2,359 407 2,578 35 125 261 3,406 5,765

K 0 1 9 39 190 230 469 469

L 4,262 386 3,839 18 139 399 4,781 9,043

M 1,568 238 1,993 45 215 381 2,872 4,440

N 0 0 1 0 4 17 22 22

O 0 0 0 0 0 1 1 1

Q 132 629 4,536 222 626 311 6,324 6,456

2015 A 63 331 421 110 44 16 922 985

B 178 64 408 3 3 25 503 681

C 277 102 301 170 357 194 1,124 1,401

D 1,281 229 1,354 29 8 123 1,743 3,024

E 266 153 479 115 255 144 1,146 1,412

F 982 140 836 173 42 150 1,341 2,323

G 46 48 106 82 303 225 764 810

H 1,787 213 1,523 56 103 266 2,161 3,948

I 379 98 392 99 204 144 937 1,316

J 1,447 184 1,802 60 120 190 2,356 3,803

K 0 0 5 37 207 223 472 472

L 2,430 243 2,921 59 142 296 3,661 6,091

M 779 249 1,817 58 269 262 2,655 3,434

N 0 0 0 0 5 3 8 8

Q 48 1,999 4,112 519 678 262 7,570 7,618

Santa Barbara Island 2011 A 2,922 124 1,371 9 11 92 1,607 4,529

B 17 82 145 96 55 45 423 440

C 282 57 298 9 8 29 401 683

D 720 54 532 20 7 40 653 1,373

E 0 42 68 31 53 38 232 232

2012 A 2,686 108 1,393 8 7 91 1,607 4,293

B 15 73 297 71 61 53 555 570

C 225 86 395 23 11 22 537 762

D 632 104 663 15 27 51 860 1,492

E 0 81 114 104 102 54 455 455

A 2,193 225 2,076 19 65 147 2,532 4,725
33

Table 5. (Continued)

Island Year Area

PupsJuvenilesAdult femalesYoung malesSub-adult malesAdult malesNon-pup totalTotal

California sea lion (Continued)

Santa Barbara Island 2013 B 3 91 214 13 73 62 453 456

(Continued) C 147 136 356 1 12 23 528 675

D 575 137 801 34 44 65 1,081 1,656

E 0 26 48 33 64 54 225 225

2014 A 1,913 199 2,107 6 13 114 2,439 4,352

B 6 30 292 79 64 41 506 512

C 234 20 410 0 0 21 451 685

D 345 38 864 16 18 52 988 1,333

E 0 9 112 10 58 56 245 245

2015 A 644 101 904 26 29 108 1,168 1,812

B 1 66 85 46 63 28 288 289

C 37 59 165 12 12 19 267 304

D 182 89 398 54 44 65 650 832

E 0 33 0 65 67 51 216 216

Santa Catalina Island 2011 502 17 117 221 21 2 4 365 382

523 0 0 0 1 0 1 2 2

528 0 1 30 0 0 1 32 32

2012 502 0 31 11 0 0 1 43 43

523 31 32 94 6 4 5 141 172

524 0 5 30 0 0 0 35 35

528 0 6 12 0 0 1 19 19

2013 502 20 102 281 5 10 8 406 426

522 0 1 3 0 0 0 4 4

528 0 6 10 0 0 0 16 16

2014 502 17 26 194 22 3 11 256 273

522 2 10 53 2 0 1 66 68

2015 502 11 139 442 29 11 4 625 636

522 0 10 0 30 0 0 40 40

528 0 8 3 19 0 0 30 30

Santa Cruz Island 2011 641 0 203 198 5 0 0 406 406

648 0 13 10 0 0 0 23 23

655 1 69 475 11 38 3 596 597

2012 641 0 170 611 27 2 1 811 811

655 0 232 467 29 18 14 760 760

2013 641 0 8 30 0 0 1 39 39

643 0 30 64 0 0 0 94 94

655 0 412 841 31 34 18 1,336 1,336

2014 641 0 45 147 27 2 0 221 221

655 0 74 503 29 30 13 649 649

2015 641 0 17 0 22 0 0 39 39

648 0 94 324 3 8 3 432 432

655 1 89 774 310 19 11 1,203 1,204

Santa Rosa Island 2011 617 0 166 388 0 5 2 561 561

621 0 181 82 0 1 1 265 265

624 0 18 45 6 3 2 74 74

2012 617 0 458 731 0 10 1 1,200 1,200

621 0 7 1 24 8 3 43 43

624 3 144 103 63 20 8 338 341
34

Table 5. (Continued)

Island Year Area

PupsJuvenilesAdult femalesYoung malesSub-adult malesAdult malesNon-pup totalTotal

California sea lion (Continued)

Santa Rosa Island 2013 617 0 37 172 0 5 3 217 217

(Continued) 621 0 42 23 0 2 0 67 67

624 3 76 366 5 25 12 484 487

2014 617 0 47 259 88 4 2 400 400

621 0 39 84 22 6 1 152 152

624 1 23 308 8 2 4 345 346

2015 617 0 164 92 139 9 6 410 410

621 0 33 0 95 8 3 139 139

622 0 0 0 1 0 0 1 1

624 0 0 0 1 8 7 16 16

625A 0 0 0 1 0 1 2 2

Northern elephant seal

San Clemente Island 2012 406 0 0 0 1 4 2 7 7

2013 406 0 0 0 0 0 0 0 0

2014 406 0 0 0 1 3 2 6 6

2015 406 0 0 0 2 0 1 3 3

407 0 0 0 0 2 0 2 2

San Miguel Island 2012 A 0 1 0 0 67 94 162 162

B 0 0 0 0 5 0 5 5

C 0 0 0 1 117 80 198 198

D 0 0 0 5 43 4 52 52

E 0 0 0 2 78 40 120 120

F 0 4 0 17 30 10 61 61

G 0 4 0 18 126 49 197 197

H 0 6 0 44 614 59 723 723

I 0 1 0 1 1 0 3 3

J 0 3 0 17 262 48 330 330

K 0 0 0 21 7 0 28 28

L 0 1 0 2 29 11 43 43

N 0 0 0 1 9 0 10 10

2013 D 0 1 0 3 0 0 4 4

E 0 1 0 6 48 6 61 61

F 0 7 0 11 54 8 80 80

G 0 3 0 20 136 32 191 191

H 0 17 0 140 404 109 670 670

I 0 4 0 19 89 8 120 120

J 0 5 0 24 235 51 315 315

K 0 4 0 16 38 5 63 63

L 0 1 0 4 40 11 56 56

N 0 2 0 8 12 2 24 24

A 0 9 0 4 67 23 103 103

B 0 3 0 3 50 8 64 64

C 0 9 0 40 167 41 257 257

D 0 0 0 5 24 1 30 30

2014 A 0 3 0 11 59 71 144 144

B 0 0 0 10 15 23 48 48

C 0 0 0 51 117 81 249 249

D 0 0 0 18 32 5 55 55
35

Table 5. (Continued)

Island Year Area

PupsJuvenilesAdult femalesYoung malesSub-adult malesAdult malesNon-pup totalTotal

Northern elephant seal (Continued)

San Miguel Island 2014 E 0 0 0 24 49 37 110 110

(Continued) F 0 0 0 17 40 33 90 90

G 0 2 0 46 120 54 222 222

H 0 1 0 59 334 416 810 810

I 0 4 0 97 205 40 346 346

J 0 0 0 43 109 135 287 287

K 0 0 0 17 67 12 96 96

L 0 0 0 12 16 44 72 72

M 0 1 0 14 83 6 104 104

N 0 0 0 2 2 1 5 5

2015 A 0 0 0 6 51 3 60 60

B 0 1 0 7 59 32 99 99

C 0 4 0 73 244 20 341 341

D 0 0 0 15 10 0 25 25

E 0 3 0 22 89 10 124 124

F 0 0 0 20 64 3 87 87

G 0 4 0 37 117 29 187 187

H 0 2 0 95 553 160 810 810

I 0 2 0 79 294 19 394 394

J 0 0 0 38 246 35 319 319

K 0 4 0 31 109 17 161 161

L 0 1 0 2 61 6 70 70

M 0 0 0 7 71 25 103 103

N 0 0 0 2 8 0 10 10

San Nicolas Island 2011 C 0 0 0 0 13 10 23 23

D 0 0 0 0 23 17 40 40

E 0 2 0 0 55 51 108 108

F 0 0 0 0 1 12 13 13

G 0 0 0 0 0 2 2 2

H 0 1 0 0 1 4 6 6

J 0 0 0 0 2 7 9 9

K 0 1 0 3 125 76 205 208

M 0 0 0 0 49 31 80 80

Q 0 0 0 0 63 63 126 126

2012 A 0 1 0 0 5 2 8 8

B 0 0 0 0 7 45 52 52

C 0 0 0 0 6 4 10 10

D 0 1 0 0 20 20 41 41

E 0 0 0 19 70 53 142 142

F 0 1 0 0 7 1 9 9

G 0 0 0 4 2 3 9 9

H 0 1 0 1 1 1 4 4

I 0 2 0 0 2 0 4 4

J 0 0 0 0 2 0 2 2

K 0 0 0 28 159 95 282 282

L 0 1 0 1 1 0 3 3

M 0 0 0 1 36 60 97 97

Q 0 2 0 4 71 62 139 139
36

Table 5. (Continued)

Island Year Area

PupsJuvenilesAdult femalesYoung malesSub-adult malesAdult malesNon-pup totalTotal

Northern elephant seal (Continued)

San Nicolas Island 2013 A 0 3 0 1 30 8 42 42

(Continued) B 0 1 0 1 8 1 11 11

C 0 0 0 4 23 3 30 30

D 0 3 0 10 13 6 32 32

E 0 3 0 12 53 24 92 92

F 0 2 0 4 22 2 30 30

G 0 1 0 1 0 1 3 3

H 0 3 0 1 1 0 5 5

I 0 2 0 1 7 2 12 12

J 0 0 0 0 11 3 14 14

K 0 4 0 26 122 20 172 172

M 0 3 0 9 82 25 119 119

N 0 0 0 7 32 1 40 40

Q 0 3 0 14 85 29 131 131

2014 A 0 0 0 2 4 7 13 13

B 0 0 0 0 8 7 15 15

C 0 0 0 10 13 6 29 29

D 0 1 0 6 7 10 24 24

E 0 0 0 9 43 36 88 88

F 0 0 0 5 4 2 11 11

G 0 0 0 1 3 4 8 8

H 0 0 0 0 13 2 15 15

I 0 0 0 0 10 19 29 29

J 0 0 0 0 9 17 26 26

K 0 0 0 46 95 63 204 204

L 0 0 0 2 3 0 5 5

M 0 0 0 22 82 50 154 154

N 0 0 0 2 13 6 21 21

O 0 0 0 5 35 22 62 62

Q 0 2 0 12 53 44 111 111

2015 A 0 0 0 2 5 4 11 11

B 0 0 0 1 3 0 4 4

C 0 1 0 7 31 2 41 41

D 0 0 0 18 18 3 39 39

E 0 1 0 53 43 11 108 108

F 0 0 0 11 21 0 32 32

G 0 0 0 3 7 0 10 10

H 0 0 0 2 7 0 9 9

I 0 0 0 6 19 5 30 30

J 0 1 0 2 15 6 24 24

K 0 2 0 37 172 57 268 268

L 0 0 0 5 0 0 5 5

M 0 0 0 33 140 11 184 184

N 0 0 0 4 17 2 23 23

Q 0 1 0 24 93 26 144 144

Santa Barbara Island 2011 D 0 0 0 0 1 3 4 4

2012 A 0 0 0 0 3 2 5 5

2013 A 0 0 0 0 2 0 2 2
37

Table 5. (Continued)

Island Year Area

PupsJuvenilesAdult femalesYoung malesSub-adult malesAdult malesNon-pup totalTotal

Northern elephant seal (Continued)

Santa Barbara Island 2013 D 0 2 0 2 1 1 6 6

(Continued) 2014 D 0 0 0 2 6 0 8 8

2015 B 0 1 0 0 0 0 1 1

D 0 0 0 3 7 0 10 10

Santa Rosa Island 2015 611 0 0 0 2 0 0 2 2

621 0 1 0 5 40 4 50 50

622 0 0 0 12 148 33 193 193

624 0 0 0 33 140 19 192 192

626 0 0 0 14 103 40 157 157

625A 0 0 0 23 92 31 146 146

625B 0 0 0 7 6 0 13 13

625C 0 0 0 1 51 11 63 63

Pacific harbor seal

Anacapa Island 2015 680 0 0 0 0 0 0 0 2

Richardson Rock 2015 103 0 0 0 0 0 0 0 3

San Clemente Island 2014 406 8

411 8

2015 402 13

404 64

406 22

407 2

411 15

San Miguel Island 2012 A 7

B 45

C 17

D 34

E 77

F 29

G 37

H 27

J 108

L 68

N 110

2013 A 50

B 10

C 20

D 64

E 56

F 29

G 1

H 14

J 112

L 87

N 122

2014 A 45

B 10

C 50

D 86
38

Table 5. (Continued)

Island Year Area

PupsJuvenilesAdult femalesYoung malesSub-adult malesAdult malesNon-pup totalTotal

Pacific harbor seal (Continued)

San Miguel Island 2014 E 70

(Continued) F 28

G 1

H 21

J 133

L 38

M 9

N 182

2015 A 19

B 7

C 57

D 100

E 54

F 29

H 1

J 60

M 17

N 206

San Nicolas Island 2011 D 8

E 2

F 6

I 11

J 6

L 73

M 22

Q 101

2012 D 27

F 5

J 10

L 119

M 47

Q 118

2013 A 16

C 25

D 46

E 12

F 50

I 7

J 12

K 2

L 86

M 58

N 111

Q 180

2014 A 15

C 47

D 20

E 31
39

Table 5. (Continued)

Island Year Area

PupsJuvenilesAdult femalesYoung malesSub-adult malesAdult malesNon-pup totalTotal

Pacific harbor seal (Continued)

San Nicolas Island 2014 F 43

(Continued) I 4

J 12

L 139

M 19

N 71

O 38

Q 171

2015 A 1

C 37

D 3

E 31

F 14

I 3

J 6

L 1

M 5

N 60

Q 98

Santa Barbara Island 2012 B 5

C 4

D 9

2013 A 2

D 6

2015 B 5

C 1

D 3

Santa Cruz Island 2015 643 28

647 2

655 9

656 142

Santa Rosa Island 2015 615 83

618 19

624 55

626 90

Steller sea lion

San Nicolas Island 2013 H 0 1 0 0 0 0 1 1

1Richardson Rock not photographed in 2013.
40

Table 6. Island-area mean and standard deviation (SD) of age/sex class counts and category total counts of California sea lions, 

northern elephant seals, and Pacific harbor seals obtained from aerial photographs taken during surveys of the Channel Islands

conducted during July 2011-2015. Refer to Figures 3 and 4 for location of island-areas. Only island-areas with animals and islands 

having multiple years of data are included. No counts made where blanks appear.

Pups Juveniles

Adult

females

Young

males

Sub-adult

males

Adult

males

Non-pup

total Total

Area Mean SD Mean SD Mean SD Mean SD Mean SD Mean SD Mean SD Mean SD

California sea lion

Anacapa Island

680 44.4 8.3 311.0 99.1 566.8 164.2 142.0 64.7 26.8 16.0 20.6 4.7 1,067.2 126.3 1,111.6 122.6

Richardson Rock

103 0.3 0.5 60.3 12.3 200.3 130.2 7.8 6.7 19.3 3.3 11.8 3.7 299.3 148.0 299.5 147.8

San Clemente Island

404 0.5 0.6 25.8 20.5 33.5 14.7 19.5 12.2 13.3 5.3 5.5 3.7 97.5 27.1 98.0 27.6

406 1,669.4 892.6 248.0 81.7 1,670.0 403.5 19.0 8.8 43.6 15.3 136.4 19.4 2,117.0 473.9 3,786.4 1,238.3

407 492.6 221.5 144.4 51.3 846.8 295.6 66.6 27.9 70.4 37.1 78.4 17.4 1,206.6 316.6 1,699.2 467.0

410 0.0 0.0 23.0 2.8 18.0 17.0 3.5 4.9 1.0 1.4 0.0 0.0 45.5 20.5 45.5 20.5

411 12.2 10.8 168.8 93.1 567.4 189.6 6.2 9.3 7.8 2.9 11.2 4.7 761.4 207.4 773.6 208.6

San Miguel Island

A 12.8 6.9 1,801.4 1,480.2 1,399.0 470.5 151.0 66.6 198.4 28.9 63.6 13.4 3,613.4 1,795.2 3,626.2 1,801.2

B 10.2 11.1 376.2 403.0 797.4 789.8 26.4 31.1 22.8 16.8 15.4 11.2 1,238.2 1,211.0 1,248.4 1,221.5

C 547.6 154.7 828.8 587.0 2,168.8 392.0 37.8 20.8 46.0 19.3 55.8 11.8 3,137.2 921.4 3,684.8 857.1

D 0.0 0.0 0.0 0.0 0.8 0.8 0.4 0.5 6.2 6.9 11.8 8.7 19.2 15.5 19.2 15.5

E 0.0 0.0 0.2 0.4 1.2 1.8 4.0 1.9 20.4 4.2 26.6 5.4 52.4 5.9 52.4 5.9

F 1.8 2.7 12.6 9.8 13.6 9.5 113.2 62.9 413.4 122.2 521.2 223.4 1,074.0 349.1 1,075.8 347.2

G 2,621.8 580.3 303.0 239.3 1,894.0 300.8 82.8 32.3 153.2 121.7 226.2 78.1 2,659.2 553.8 5,281.0 824.6

H 15,360.4 3,340.1 1,759.0 993.1 11,760.6 554.0 134.1 808.2 111.4 1,273.2 113.2 1,709.0 16,155.0 2,507.8 31,515.4 4,935.2

I 22.2 33.9 22.4 17.5 97.2 125.1 211.0 82.8 634.0 272.3 504.2 108.0 1,468.8 528.0 1,491.0 555.7

J 4,088.2 665.2 1,049.2 211.1 4,084.4 483.8 404.8 158.0 758.2 188.3 397.6 32.3 6,694.2 579.9 10,782.4 950.0

K 0.0 0.0 0.0 0.0 0.5 0.6 0.0 0.0 2.8 2.2 6.5 6.2 9.8 7.4 9.8 7.4

L 33.6 27.8 868.4 469.1 763.8 369.8 41.6 42.3 25.4 14.9 20.6 6.7 1,719.8 395.7 1,753.4 381.2

M 0.0 0.0 0.0 0.0 0.0 0.0 1.0 1.7 1.3 1.5 2.7 4.6 5.0 7.8 5.0 7.8

N 0.0 0.0 1.2 1.6 2.0 2.9 1.2 1.8 1.4 1.9 2.0 1.6 7.8 9.5 7.8 9.5

O 690.8 192.0 65.0 29.8 767.8 150.4 0.6 0.9 1.6 1.5 75.8 11.6 910.8 180.0 1,601.6 354.5
41

Table 6. (Continued)

Pups Juveniles

Adult

females

Young

males

Sub-adult

males

Adult

males

Non-pup

total Total

Area Mean SD Mean SD Mean SD Mean SD Mean SD Mean SD Mean SD Mean SD

California sea lion (Continued)

San Nicolas Island

A 155.8 85.6 421.4 160.1 686.2 328.2 75.0 65.6 54.2 31.5 20.6 6.8 1,257.4 334.4 1,413.2 368.0

B 473.0 186.5 104.0 41.7 539.0 126.0 4.8 3.5 3.4 1.7 30.8 7.2 682.0 164.6 1,155.0 294.8

C 593.6 192.1 117.0 94.0 389.4 138.2 100.8 49.1 255.2 81.0 215.8 34.3 1,078.2 315.7 1,671.8 288.4

D 3,656.8 1,797.1 373.0 260.1 2,093.0 434.9 14.4 11.2 12.2 7.7 165.6 31.2 2,658.2 597.2 6,315.0 2,094.9

E 742.4 383.2 263.8 105.2 759.8 187.8 124.4 30.4 248.2 18.4 190.2 36.8 1,586.4 298.2 2,328.8 563.6

F 2,257.6 1,047.4 304.8 174.3 1,445.8 382.1 50.6 70.5 25.2 11.6 177.6 32.3 2,004.0 463.8 4,261.6 1,241.0

G 199.6 139.7 120.6 65.8 234.8 88.1 119.0 46.0 295.6 45.3 237.6 59.5 1,007.6 227.6 1,207.2 266.2

H 3,665.4 1,715.1 423.4 236.3 2,193.4 391.7 67.4 33.8 94.0 16.8 325.6 46.3 3,103.8 568.5 6,769.2 2,006.8

I 1,081.0 569.0 221.6 154.9 619.6 140.4 92.8 26.7 179.0 37.8 166.8 28.6 1,279.8 284.7 2,360.8 699.8

J 2,542.4 963.4 424.2 244.7 2,212.8 334.4 73.6 50.6 142.6 35.7 240.8 32.0 3,094.0 571.6 5,636.2 1,181.7

K 0.0 0.0 1.2 0.8 4.2 3.3 40.8 23.5 178.6 48.5 196.0 44.3 420.8 78.9 420.8 78.9

L 4,269.2 1,438.7 486.4 252.9 3,424.8 557.3 59.6 40.5 131.8 39.7 333.0 54.1 4,435.6 818.3 8,704.8 1,793.4

M 1,458.4 495.1 249.8 78.6 1,758.6 379.0 74.4 43.2 253.8 35.9 301.6 54.6 2,638.2 502.0 4,096.6 479.0

N 0.0 0.0 0.0 0.0 0.3 0.5 0.0 0.0 2.3 2.6 6.8 7.1 9.3 9.0 9.3 9.0

O 0.0 0.0 0.0 0.0 0.0 1.0 1.0 1.0

Q 71.6 34.2 1,537.0 695.1 3,534.2 1,873.5 314.2 124.8 572.6 109.7 256.6 63.8 6,214.6 2,283.4 6,286.2 2,284.1

Santa Barbara Island

A 2,071.6 891.4 151.4 56.7 1,570.2 514.5 13.6 8.6 25.0 23.9 110.4 22.8 1,870.6 590.2 3,942.2 1,202.7

B 8.4 7.2 68.4 23.4 206.6 92.3 61.0 32.3 63.2 6.5 45.8 12.8 445.0 101.3 453.4 105.2

C 185.0 95.9 71.6 43.0 324.8 99.3 9.0 9.4 8.6 5.1 22.8 3.8 436.8 110.3 621.8 181.1

D 490.8 221.5 84.4 39.5 651.6 191.2 27.8 16.5 28.0 16.2 54.6 10.6 846.4 194.5 1,337.2 309.1

E 0.0 0.0 38.2 26.8 68.4 47.6 48.6 36.7 68.8 19.3 50.6 7.3 274.6 101.4 274.6 101.4

Santa Catalina Island

502 13.0 8.0 83.0 51.5 229.8 155.6 15.4 12.3 5.2 5.0 5.6 3.9 339.0 213.0 352.0 217.2

522 0.7 1.2 7.0 5.2 18.7 29.8 10.7 16.8 0.0 0.0 0.3 0.6 36.7 31.1 37.3 32.1

523 15.5 21.9 16.0 22.6 47.0 66.5 3.5 3.5 2.0 2.8 3.0 2.8 71.5 98.3 87.0 120.2

524 0.0 5.0 30.0 0.0 0.0 0.0 35.0 35.0

528 0.0 0.0 5.3 3.0 13.8 11.5 4.8 9.5 0.0 0.0 0.5 0.6 24.3 7.9 24.3 7.9
42

Table 6. (Continued)

Pups Juveniles

Adult

females

Young

males

Sub-adult

males

Adult

males

Non-pup

total Total

Area Mean SD Mean SD Mean SD Mean SD Mean SD Mean SD Mean SD Mean SD

California sea lion (Continued)

Santa Cruz Island

641 0.0 0.0 88.6 91.2 197.2 245.3 16.2 12.8 0.8 1.1 0.4 0.5 303.2 322.0 303.2 322.0

643 0.0 30.0 64.0 0.0 0.0 0.0 94.0 94.0

648 0.0 0.0 53.5 57.3 167.0 222.0 1.5 2.1 4.0 5.7 1.5 2.1 227.5 289.2 227.5 289.2

655 0.4 0.5 175.2 148.5 612.0 180.5 82.0 127.7 27.8 9.0 11.8 5.5 908.8 337.8 909.2 337.8

Santa Rosa Island

617 0.0 0.0 174.4 170.1 328.4 250.4 45.4 64.7 6.6 2.7 2.8 1.9 557.6 379.2 557.6 379.2

621 0.0 0.0 60.4 68.8 38.0 42.1 28.2 39.1 5.0 3.3 1.6 1.3 133.2 87.0 133.2 87.0

622 0.0 0.0 0.0 1.0 0.0 0.0 1.0 1.0

624 1.4 1.5 52.2 58.6 164.4 163.0 16.6 26.1 11.6 10.4 6.6 3.8 251.4 198.3 252.8 199.6

625A 0.0 0.0 0.0 1.0 0.0 1.0 2.0 2.0

Northern elephant seal

San Clemente Island

406 0.0 0.0 0.0 0.0 0.0 0.0 1.0 0.8 1.8 2.1 1.3 1.0 4.0 3.2 4.0 3.2

407 0.0 0.0 0.0 0.0 2.0 0.0 2.0 2.0

San Miguel Island

A 0.0 0.0 3.3 4.0 0.0 0.0 5.3 4.6 61.0 7.7 47.8 42.0 117.3 45.5 117.3 45.5

B 0.0 0.0 1.0 1.4 0.0 0.0 5.0 4.4 32.3 26.3 15.8 14.4 54.0 39.0 54.0 39.0

C 0.0 0.0 3.3 4.3 0.0 0.0 41.3 30.1 161.3 60.0 55.5 30.1 261.3 59.2 261.3 59.2

D 0.0 0.0 0.3 0.5 0.0 0.0 11.5 6.0 27.3 13.9 2.5 2.4 41.5 14.4 41.5 14.4

E 0.0 0.0 1.0 1.4 0.0 0.0 13.5 11.1 66.0 20.7 23.3 17.7 103.8 29.1 103.8 29.1

F 0.0 0.0 2.8 3.4 0.0 0.0 16.3 3.8 47.0 15.0 13.5 13.3 79.5 13.0 79.5 13.0

G 0.0 0.0 3.3 1.0 0.0 0.0 30.3 13.5 124.8 8.4 41.0 12.4 199.3 15.7 199.3 15.7

H 0.0 0.0 6.5 7.3 0.0 84.5 42.7 476.3 129.5 186.0 158.8 0.0 753.3 69.0 753.3 69.0

I 0.0 0.0 2.8 1.5 0.0 0.0 49.0 46.2 147.3 128.7 16.8 17.3 215.8 185.4 215.8 185.4

J 0.0 0.0 2.0 2.4 0.0 0.0 30.5 12.1 213.0 70.2 67.3 45.7 312.8 18.3 312.8 18.3

K 0.0 0.0 2.0 2.3 0.0 0.0 21.3 6.8 55.3 43.4 8.5 7.5 87.0 56.6 87.0 56.6

L 0.0 0.0 0.8 0.5 0.0 0.0 5.0 4.8 36.5 19.1 18.0 17.5 60.3 13.5 60.3 13.5

M 0.0 0.0 0.5 0.7 0.0 0.0 10.5 4.9 77.0 8.5 15.5 13.4 103.5 0.7 103.5 0.7

N 0.0 0.0 0.5 1.0 0.0 0.0 3.3 3.2 7.8 4.2 0.8 1.0 12.3 8.2 12.3 8.2
43

Table 6. (Continued)

Pups Juveniles

Adult

females

Young

males

Sub-adult

males

Adult

males

Non-pup

total Total

Area Mean SD Mean SD Mean SD Mean SD Mean SD Mean SD Mean SD Mean SD

Northern elephant seal (Continued)

San Nicolas Island

A 0.0 0.0 1.0 1.4 0.0 0.0 1.3 1.0 11.0 12.7 5.3 2.8 18.5 15.8 18.5 15.8

B 0.0 0.0 0.3 0.5 0.0 0.0 0.5 0.6 6.5 2.4 13.3 21.4 20.5 21.5 20.5 21.5

C 0.0 0.0 0.2 0.4 0.0 0.0 4.2 4.4 17.2 9.8 5.0 3.2 26.6 11.3 26.6 11.3

D 0.0 0.0 1.0 1.2 0.0 0.0 6.8 7.6 16.2 6.3 11.2 7.2 35.2 7.2 35.2 7.2

E 0.0 0.0 1.2 1.3 0.0 0.0 18.6 20.4 52.8 11.1 35.0 17.9 107.6 21.3 107.6 21.3

F 0.0 0.0 0.6 0.9 0.0 0.0 4.0 4.5 11.0 9.8 3.4 4.9 19.0 11.1 19.0 11.1

G 0.0 0.0 0.2 0.4 0.0 0.0 1.8 1.6 2.4 2.9 2.0 1.6 6.4 3.6 6.4 3.6

H 0.0 0.0 1.0 1.2 0.0 0.0 0.8 0.8 4.6 5.4 1.4 1.7 7.8 4.4 7.8 4.4

I 0.0 0.0 1.0 1.2 0.0 0.0 1.8 2.9 9.5 7.1 6.5 8.6 18.8 12.8 18.8 12.8

J 0.0 0.0 0.2 0.4 0.0 0.0 0.4 0.9 7.8 5.7 6.6 6.4 15.0 10.1 15.0 10.1

K 0.0 0.0 1.4 1.7 0.0 0.0 28.0 16.1 134.6 30.9 62.2 27.7 226.2 46.7 226.8 46.4

L 0.0 0.0 0.3 0.6 0.0 0.0 2.7 2.1 1.3 1.5 0.0 0.0 4.3 1.2 4.3 1.2

M 0.0 0.0 0.6 1.3 0.0 0.0 13.0 14.2 77.8 40.3 35.4 19.6 126.8 42.3 126.8 42.3

N 0.0 0.0 0.0 0.0 0.0 0.0 4.3 2.5 20.7 10.0 3.0 2.6 28.0 10.4 28.0 10.4

O 0.0 0.0 0.0 5.0 35.0 22.0 62.0 62.0

Q 0.0 0.0 1.6 1.1 0.0 0.0 10.8 9.3 73.0 16.2 44.8 17.5 130.2 12.8 130.2 12.8

Santa Barbara Island

A 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 2.5 0.7 1.0 1.4 3.5 2.1 3.5 2.1

B 0.0 1.0 0.0 0.0 0.0 0.0 1.0 1.0

D 0.0 0.0 0.5 1.0 0.0 0.0 1.8 1.3 3.8 3.2 1.0 1.4 7.0 2.6 7.0 2.6

Pacific harbor seal

San Clemente Island

402 13.0

404 64.0

406 15.0 9.9

407 2.0

411 11.5 4.9

San Miguel Island

A 30.3 20.6
44

Table 6. (Continued)

Pups Juveniles

Adult

females

Young

males

Sub-adult

males

Adult

males

Non-pup

total Total

Area Mean SD Mean SD Mean SD Mean SD Mean SD Mean SD Mean SD Mean SD

Pacific harbor seal (Continued)

San Miguel Island

B 18.0 18.1

C 36.0 20.4

D 71.0 28.8

E 64.3 11.1

F 28.8 0.5

G 13.0 20.8

H 15.8 11.2

J 103.3 30.8

L 64.3 24.7

M 13.0 5.7

N 155.0 46.3

San Nicolas Island

A 10.7 8.4

C 36.3 11.0

D 20.8 17.0

E 19.0 14.4

F 23.6 21.3

I 6.3 3.6

J 9.2 3.0

K 2.0

L 83.6 53.1

M 30.2 21.7

N 80.7 26.8

O 38.0

Q 133.6 39.1

Santa Barbara Island

A 2.0

B 5.0 0.0

C 2.5 2.1
45

Table 6. (Continued)

Pups Juveniles

Adult

females

Young

males

Sub-adult

males

Adult

males

Non-pup

total Total

Area Mean SD Mean SD Mean SD Mean SD Mean SD Mean SD Mean SD Mean SD

Pacific harbor seal (Continued)

Santa Barbara Island (Continued)

D 6.0 3.0
46

Table 7. Percentage mean (Mean %) and standard deviation (SD) of island-area counts for each 

age/sex class and category total for California sea lions, northern elephant seals, and Pacific 

harbor seals found in aerial photographs taken at the Channel Islands during July 2011-2015. 

Refer to Figures 3 and 4 for location of area codes. Pacific harbor seals were not counted by 

age/sex class. Areas with no animals are excluded.

Island

/Area

Pups Juveniles Adult

females

Young

males

Sub-adult

males

Adult

males

Non-pup 

total Total

Mean 

% SD

Mean 

% SD

Mean 

% SD

Mean 

% SD

Mean 

% SD

Mean 

% SD

Mean

% SD

Mean 

% SD

California sea lion

Anacapa Island

680 100.0 0.0 100.0 0.0 100.0 0.0 100.0 0.0 100.0 0.0 100.0 0.0 100.0 0.0 100.0 0.0

Richardson Rock

103 100.0 100.0 0.0 100.0 0.0 100.0 0.0 100.0 0.0 100.0 0.0 100.0 0.0 100.0 0.0

San Clemente Island

404 0.0 0.0 4.0 2.3 1.0 0.3 15.6 3.3 12.5 7.3 2.4 1.5 2.3 0.4 1.7 0.5

406 75.1 4.2 42.8 8.6 54.0 5.2 18.1 1.7 33.6 4.6 59.5 2.6 50.7 4.5 58.5 7.1

407 24.1 3.7 25.2 8.3 26.7 2.5 64.6 11.4 50.2 11.9 33.8 2.3 28.7 1.4 26.9 2.2

410 0.0 0.0 4.2 0.7 0.9 0.9 1.6 2.3 0.8 1.1 0.0 0.0 1.4 0.9 1.1 1.0

411 0.7 0.6 27.2 12.6 18.1 2.7 4.2 4.8 5.9 0.7 4.7 1.8 18.2 2.6 12.8 3.9

San Miguel Island

A 0.1 0.0 23.5 11.5 5.8 1.4 9.6 5.2 6.5 1.3 2.0 0.3 9.1 3.5 5.7 2.1

B 0.1 0.1 7.2 8.4 3.5 3.6 1.7 1.9 0.7 0.6 0.5 0.4 3.4 3.5 2.2 2.3

C 2.5 0.9 10.5 4.4 9.1 0.7 2.4 1.5 1.5 0.7 1.7 0.4 8.0 1.3 5.9 0.8

D 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.2 0.2 0.4 0.2 0.1 0.0 0.0 0.0

E 0.0 0.0 0.0 0.0 0.0 0.0 0.3 0.1 0.7 0.1 0.8 0.1 0.1 0.0 0.1 0.0

F 0.0 0.0 0.2 0.2 0.1 0.0 6.7 3.1 13.5 4.2 16.1 6.4 2.8 0.8 1.7 0.4

G 11.2 0.4 4.2 2.5 8.0 1.0 5.1 1.8 4.9 3.8 7.2 2.8 6.9 1.0 8.5 0.7

H 65.4 2.0 24.9 9.8 49.5 4.1 33.8 3.9 26.1 2.1 39.8 2.2 41.6 2.3 50.6 2.4

I 0.1 0.2 0.4 0.4 0.4 0.6 13.3 5.7 20.3 7.8 15.7 2.9 3.9 1.7 2.5 1.2

J 17.6 1.4 15.9 4.0 17.2 0.9 24.3 5.9 24.6 6.5 12.5 1.3 17.3 0.7 17.4 0.8

K 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.0 0.3 0.1 0.0 0.0 0.0 0.0

L 0.2 0.1 12.2 3.8 3.2 1.6 2.6 2.7 0.8 0.5 0.6 0.2 4.5 1.1 2.8 0.5

M 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.2 0.1 0.1 0.1 0.2 0.0 0.0 0.0 0.0

N 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.2 0.1 0.1 0.1 0.0 0.0 0.0 0.0 0.0

O 2.9 0.4 0.9 0.2 3.2 0.4 0.0 0.1 0.1 0.0 2.4 0.3 2.3 0.3 2.6 0.3

San Nicolas Island

A 0.7 0.1 9.1 4.9 3.4 1.3 5.9 5.7 2.1 1.1 0.7 0.2 4.0 0.9 2.7 0.5

B 2.2 0.4 2.1 0.7 2.7 0.4 0.4 0.3 0.1 0.1 1.1 0.1 2.2 0.4 2.2 0.3

C 2.9 0.5 2.3 1.7 1.9 0.4 8.3 3.3 10.3 2.3 7.5 0.4 3.4 0.7 3.2 0.6

D 16.7 2.3 7.0 2.2 10.6 2.0 1.2 0.8 0.5 0.3 5.8 0.7 8.5 1.4 11.7 2.4

E 3.4 0.5 5.5 2.6 3.8 0.6 10.7 3.8 10.3 1.3 6.6 0.5 5.1 0.8 4.4 0.4

F 10.5 0.5 5.9 2.2 7.3 1.5 3.5 4.4 1.0 0.4 6.2 0.3 6.4 1.0 8.0 1.2

G 0.8 0.3 2.4 1.3 1.2 0.3 10.1 3.9 12.1 0.7 8.2 1.4 3.2 0.3 2.3 0.2

H 17.1 1.3 8.0 2.0 11.2 2.4 5.6 2.4 3.8 0.3 11.4 1.0 10.0 1.7 12.7 2.1

I 4.9 0.7 4.1 1.3 3.1 0.6 7.7 1.1 7.3 0.5 5.8 0.3 4.1 0.4 4.4 0.6

J 12.3 1.3 8.0 2.3 11.2 1.0 5.9 3.0 5.9 1.6 8.5 1.2 9.9 0.9 10.7 0.6

K 0.0 0.0 0.0 0.0 0.0 0.0 3.6 2.7 7.2 1.1 6.9 1.6 1.4 0.3 0.8 0.3

L 20.9 2.3 9.3 2.0 17.4 1.6 4.8 2.5 5.3 1.1 11.6 0.2 14.1 1.1 16.5 0.7

M 7.1 0.9 5.0 0.9 8.9 1.3 6.1 2.5 10.6 2.1 10.5 0.5 8.4 0.8 7.9 0.9

N 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.1 0.2 0.2 0.0 0.0 0.0 0.0

O 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
47

Table 7. (Continued)

Island

/Area

Pups Juveniles Adult

females

Young

males

Sub-adult

males

Adult

males

Non-pup 

total Total

Mean 

% SD

Mean 

% SD

Mean 

% SD

Mean 

% SD

Mean 

% SD

Mean 

% SD

Mean

% SD

Mean 

% SD

California sea lion (Continued)

San Nicolas Island (Continued)

Q 0.4 0.2 31.3 14.2 17.2 8.0 26.2 8.1 23.3 1.8 8.9 1.5 19.5 6.1 12.5 5.9

Santa Barbara Island

A 75.2 0.9 38.3 16.9 55.8 4.2 9.3 6.5 11.8 8.3 38.6 3.2 47.8 5.3 58.7 4.1

B 0.3 0.2 16.6 4.7 7.1 2.0 39.4 24.5 34.0 6.8 16.1 3.7 11.6 1.7 7.0 1.0

C 6.4 2.0 16.1 5.8 11.6 1.5 4.6 4.2 4.3 2.5 8.2 2.1 11.3 1.5 9.3 0.6

D 18.1 2.7 19.7 5.5 23.3 1.4 18.8 11.2 13.5 5.8 19.2 2.8 22.0 2.0 20.6 2.2

E 0.0 0.0 9.3 6.0 2.2 1.6 28.0 14.6 36.5 9.1 17.9 2.2 7.3 2.7 4.4 1.6

Santa Catalina Island

502 97.9 4.7 79.3 22.5 85.1 14.2 84.9 26.9 100.0 0.0 86.0 15.9 83.1 14.6 84.3 12.7

522 3.5 6.1 11.7 14.2 7.5 12.1 15.6 20.2 0.0 0.0 2.8 4.8 9.1 10.2 8.8 9.9

523 0.0 0.0 20.9 29.6 3.7 5.3 2.3 3.2 0.0 0.0 15.5 1.7 9.3 12.4 8.2 11.0

524 0.0 6.8 20.4 0.0 0.0 0.0 14.7 13.0

528 0.0 0.0 4.9 3.0 6.0 5.0 6.1 12.2 0.0 0.0 7.7 9.0 6.0 2.3 5.6 2.0

Santa Cruz Island

641 0.0 0.0 32.3 28.0 22.3 22.9 26.8 22.7 3.3 4.6 2.4 3.3 24.3 22.0 24.3 22.0

643 6.7 6.8 0.0 0.0 0.0 6.4 6.4

648 0.0 0.0 25.8 30.0 15.5 19.8 0.5 0.6 14.8 21.0 10.7 15.2 14.0 16.7 14.0 16.7

655 100.0 0.0 56.0 24.7 70.1 17.1 73.0 22.5 90.8 12.2 93.3 8.8 68.8 16.3 68.8 16.3

Santa Rosa Island

617 0.0 0.0 54.2 24.5 66.7 30.2 26.6 36.9 33.4 14.7 26.4 12.6 56.7 20.0 56.6 20.0

621 0.0 0.0 26.1 18.4 6.6 7.4 17.3 17.5 24.1 17.5 15.4 9.4 16.5 11.0 16.4 11.0

622 0.0 0.0 0.4 0.0 0.0 0.2 0.2

624 100.0 0.0 19.7 19.3 26.7 28.1 55.9 49.1 42.6 23.6 57.0 17.0 26.8 24.5 26.9 24.5

625A 0.0 0.0 0.4 0.0 5.9 0.4 0.4

Northern elephant seal

San Clemente Island

406 100.0 0.0 66.7 57.7 100.0 0.0 86.7 23.1 86.7 23.1

407 0.0 100.0 0.0 40.0 40.0

San Miguel Island

A 11.5 11.9 1.3 1.1 4.3 1.1 9.9 9.8 5.3 2.6 5.3 2.6

B 2.3 2.7 1.2 1.0 2.1 1.5 3.5 3.8 2.2 1.5 2.2 1.5

C 8.2 9.7 10.7 6.9 10.6 2.0 11.9 6.4 11.1 1.5 11.1 1.5

D 0.3 0.7 2.9 1.4 1.6 1.3 0.4 0.4 1.5 1.0 1.5 1.0

E 4.0 6.9 3.6 2.1 4.4 0.9 4.7 3.7 4.5 1.3 4.5 1.3

F 7.7 9.6 6.4 4.6 3.1 0.7 2.4 1.1 3.4 0.4 3.4 0.4

G 15.4 7.3 10.0 3.2 8.6 1.9 9.2 2.9 8.7 1.5 8.7 1.5

H 18.6 10.9 29.1 14.1 32.2 8.1 34.7 13.7 32.5 3.6 32.5 3.6

I 14.2 14.9 12.1 10.3 9.5 7.6 3.0 2.3 8.3 6.6 8.3 6.6

J 5.6 7.2 10.0 2.3 14.3 4.6 13.2 3.0 13.7 3.0 13.7 3.0

K 6.3 9.0 8.2 5.5 3.5 2.4 1.9 2.0 3.5 1.8 3.5 1.8

L 2.8 2.5 1.5 1.0 2.3 0.8 3.2 1.2 2.6 0.2 2.6 0.2

M 4.5 6.4 2.5 1.2 5.1 2.2 3.8 4.5 3.8 0.2 3.8 0.2

N 0.8 1.5 1.1 1.0 0.5 0.3 0.2 0.3 0.6 0.4 0.6 0.4

San Nicolas Island

A 5.5 6.3 0.9 0.7 2.3 2.5 3.1 2.4 2.4 2.2 2.4 2.2
48

Table 7. (Continued)

Island

/Area

Pups Juveniles Adult

females

Young

males

Sub-adult

males

Adult

males

Non-pup 

total Total

Mean 

% SD

Mean 

% SD

Mean 

% SD

Mean 

% SD

Mean 

% SD

Mean 

% SD

Mean

% SD

Mean 

% SD

Northern elephant seal (Continued)

San Nicolas Island (Continued)

B 0.9 1.8 0.4 0.5 1.5 0.7 4.0 6.1 2.6 2.7 2.6 2.7

C 3.3 7.5 3.2 3.4 3.7 1.4 2.2 1.0 3.4 1.3 3.4 1.2

D 11.0 13.6 4.9 5.0 3.9 2.1 4.5 1.6 4.6 1.3 4.6 1.3

E 15.5 20.6 15.8 13.3 12.7 4.4 14.8 4.4 14.1 3.4 14.0 3.3

F 3.7 5.2 2.8 2.6 2.2 1.8 1.4 1.8 2.4 1.3 2.4 1.3

G 0.7 1.6 2.1 2.8 0.5 0.5 0.8 0.5 0.8 0.4 0.8 0.4

H 9.4 10.3 0.8 0.7 1.0 1.3 0.5 0.6 1.0 0.5 1.0 0.5

I 7.3 10.5 1.0 1.4 1.9 1.2 3.0 2.8 2.2 1.4 2.2 1.4

J 3.3 7.5 0.2 0.4 1.6 1.0 3.1 2.2 1.9 1.1 1.9 1.1

K 14.5 14.9 46.5 32.0 31.3 7.6 27.5 10.9 29.2 5.1 29.2 5.2

L 3.7 6.4 1.9 0.4 0.3 0.4 0.0 0.0 0.5 0.1 0.5 0.1

M 2.1 4.8 9.1 8.1 17.0 5.6 14.9 4.7 16.0 3.4 16.0 3.4

N 0.0 0.0 3.8 3.4 4.2 2.0 1.5 0.6 3.5 1.7 3.5 1.7

O 0.0 4.1 8.9 7.5 7.6 7.6

Q 23.3 25.6 8.7 5.8 16.8 2.2 19.9 3.5 17.0 2.6 17.0 2.6

Santa Barbara Island

A 0.0 0.0 83.3 23.6 50.0 70.7 62.5 53.0 62.5 53.0

B 100.0 0.0 0.0 9.1 9.1

D 50.0 70.7 100.0 0.0 83.3 33.3 100.0 0.0 91.5 11.8 91.5 11.8

Santa Rosa Island

611 0.0 2.1 0.0 0.0 0.3 0.3

621 100.0 5.2 6.9 2.9 6.1 6.1

622 0.0 12.4 25.5 23.9 23.7 23.7

624 0.0 34.0 24.1 13.8 23.5 23.5

626 0.0 14.4 17.8 29.0 19.2 19.2

625A 0.0 23.7 15.9 22.5 17.9 17.9

625B 0.0 7.2 1.0 0.0 1.6 1.6

625C 0.0 1.0 8.8 8.0 7.7 7.7

Pacific harbor seal

Anacapa Island

680 100.0

Richardson Rock

103 100.0

San Clemente Island

402 11.2

404 55.2

406 34.5 21.9

407 1.7

411 31.5 26.2

San Miguel Island

A 5.1 3.4

B 3.1 3.3

C 6.1 3.5

D 12.1 5.0

E 11.0 1.9
49

Table 7. (Continued)

Island

/Area

Pups Juveniles Adult

females

Young

males

Sub-adult

males

Adult

males

Non-pup 

total Total

Mean 

% SD

Mean 

% SD

Mean 

% SD

Mean 

% SD

Mean 

% SD

Mean 

% SD

Mean

% SD

Mean 

% SD

Pacific harbor seal (Continued)

San Miguel Island (Continued)

F 4.9 0.5

G 2.3 3.7

H 2.7 1.9

J 17.5 4.4

L 11.1 5.0

M 2.2 1.2

N 26.4 8.0

San Nicolas Island

A 1.8 1.3

C 8.7 5.2

D 4.8 3.1

E 5.0 5.0

F 5.0 2.9

I 1.9 1.9

J 2.4 0.5

K 0.3

L 21.2 14.4

M 7.7 5.2

N 17.7 5.8

O 6.2

Q 35.2 6.5

Santa Barbara Island

A 25.0

B 41.7 19.6

C 16.7 7.9

D 52.8 21.0

Santa Cruz Island

643 15.5

647 1.1

655 5.0

656 78.5

Santa Rosa Island

615 33.6

618 7.7

624 22.3

626 36.4

Steller sea lion

San Nicolas Island

H 100.0 100.0 100.0

1Only one northern elephant seal census conducted at Santa Rosa Island, in 2015.
50

Table 8. Number of California sea lions, northern elephant seals, and Pacific harbor seals 

counted by age/sex class and category total from photographs of haulout sites within Area H at 

San Miguel Island taken during aerial photographic surveys conducted in July 2011-2015. No 

counts obtained for blank cells and only sites with animals are included. Refer to Figure 5 for 

location of haulout sites.

Haulout 

site Year Pups Juveniles Adult females

Young 

males

Subadult 

males

Adult 

males

Non-Pup 

total Total

California sea lion

40 2011 1,988 77 1,329 11 9 99 1,525 3,513

2012 2,055 164 1,286 7 5 127 1,589 3,644

2013 1,366 290 1,287 6 8 120 1,711 3,077

2014 1,600 57 1,148 1 7 141 1,354 2,954

2015 999 66 1,049 0 12 89 1,216 2,215

41 2011 731 33 559 1 1 41 635 1,366

2012 879 67 524 0 1 42 634 1,513

2013 635 82 532 0 2 43 659 1,294

2014 772 10 482 0 0 50 542 1,314

2015 425 16 373 0 7 43 439 864

52 2011 527 52 634 0 1 45 732 1,259

2012 498 76 461 1 0 35 573 1,071

2013 377 62 606 1 3 35 707 1,084

2014 396 47 494 0 0 48 589 985

2015 285 28 434 4 2 40 508 793

53 2011 1,339 131 1,347 7 10 111 1,606 2,945

2012 1,649 207 1,140 10 10 95 1,462 3,111

2013 1,071 199 1,359 7 10 99 1,674 2,745

2014 1,335 79 1,024 1 4 108 1,216 2,551

2015 944 83 1,048 25 16 98 1,270 2,214

54 2011 6,359 203 4,145 67 112 307 4,834 11,193

2012 6,971 436 3,626 142 83 281 4,568 11,539

2013 4,882 829 3,878 93 86 275 5,161 10,043

2014 5,403 162 2,809 30 85 281 3,367 8,770

2015 4,344 127 3,330 87 168 312 4,024 8,368

55 2011 166 63 320 0 0 35 418 584

2012 152 119 241 0 0 24 384 536

2013 116 162 423 1 8 28 622 738

2014 123 148 513 0 0 39 700 823

2015 61 15 218 8 1 24 266 327

56 2011 2,432 288 2,370 4 14 203 2,879 5,311

2012 3,031 338 2,021 1 11 179 2,550 5,581

2013 2,244 409 2,451 1 12 182 3,055 5,299

2014 2,178 204 1,810 0 1 199 2,214 4,392

2015 1,736 116 1,848 13 12 186 2,175 3,911

57 2011 99 17 156 0 0 19 192 291

2012 102 33 124 0 1 16 174 276

2013 67 42 183 0 4 14 243 310

2014 82 35 142 0 0 29 206 288

2015 56 11 85 1 0 16 113 169
51

Table 8. (Continued)

Haulout 

site Year Pups Juveniles Adult females

Young 

males

Subadult 

males

Adult 

males

Non-Pup 

total Total

California sea lion (Continued)

58 2011 2,676 321 1,898 275 126 183 2,803 5,479

2012 2,213 626 1,196 195 271 145 2,433 4,646

2013 1,777 859 1,522 9 27 90 2,507 4,284

2014 1,834 221 993 39 69 134 1,456 3,290

2015 1,260 264 1,035 25 23 86 1,433 2,693

59 2011 421 5 310 0 0 29 344 765

2012 414 29 256 0 0 29 314 728

2013 372 23 301 0 2 28 354 726

2014 415 5 265 1 2 32 305 720

2015 308 4 222 0 0 22 248 556

60 2011 1,248 89 720 384 554 359 2,106 3,354

2012 1,313 268 758 209 369 189 1,793 3,106

2013 738 246 643 467 696 288 2,340 3,078

2014 784 140 447 315 487 290 1,679 2,463

2015 554 112 428 321 709 304 1,874 2,428

Northern elephant seal

41 2012 0 2 0 0 0 0 2 2

52 2012 0 1 0 0 0 0 1 1

2013 0 1 0 0 0 0 1 1

2015 0 0 0 6 0 0 6 6

53 2012 0 1 0 0 0 0 1 1

2014 0 0 0 1 0 0 1 1

2015 0 0 0 6 0 0 6 6

54 2012 0 1 0 22 366 20 409 409

2013 0 6 0 97 308 85 496 496

2014 0 0 0 31 263 314 608 608

2015 0 1 0 39 450 148 638 638

56 2012 0 0 0 2 2 0 4 4

2013 0 1 0 1 8 0 10 10

2014 0 0 0 0 2 2 4 4

2015 0 0 0 10 5 0 15 15

58 2012 0 0 0 20 231 29 280 280

2013 0 3 0 40 77 19 139 139

2014 0 0 0 26 64 97 187 187

2015 0 1 0 24 93 12 130 130

60 2012 0 1 0 0 15 10 26 26

2013 0 6 0 2 11 5 24 24

2014 0 1 0 1 5 3 10 10

2015 0 0 0 10 5 0 15 15

Pacific harbor seal

40 2013 1

54 2015 1

56 2012 21

2013 13

2014 17
52

Table 8. (Continued)

Haulout 

site Year Pups Juveniles Adult females

Young 

males

Subadult 

males

Adult 

males

Non-Pup 

total Total

Pacific harbor seal (Continued)

57 2012 6

2014 4
53

Figure 1. The Channel Islands within the Southern California Bight (SCB). Not shown are 

Castle Rock (located 1 km from the NW shoreline of SMI), Richardson Rock (located 10 km 

NW from Point Bennett, SMI), and Gull Island (located 1.4 km from Punta Arena, SCruzI).
54

Figure 2. Partenavia P-68 Observer used by SWFSC to conduct aerial photographic surveys of 

pinnipeds at the Channel Islands.
55

Figure 3. Area codes for Santa Barbara Island, San Clemente Island, San Miguel Island, and San 

Nicolas Island. Area codes for San Clemente Island are from Bonnell et al. (1980). Refer to 

Appendix 1 for geographical positions (i.e., latitude and longitude) of area boundaries.
56

Figure 4. Area codes for Santa Catalina Island, Santa Cruz Island, Anacapa Island, and Santa 

Rosa Island from Bonnell et al. (1980). Areas 615, 621, 622, 624, and 625 at Santa Rosa Island 

and area 502 at Santa Catalina Island (Bonnell et al., 1980) were divided into subareas areas. 

Area 502C at Santa Catalina Island includes area 523 from Bonnell et al. (1980). Refer to 

Appendix 1 for geographical positions (i.e., latitude and longitude) of area boundaries.
57

Figure 5. Haulout site codes within Area H (Point Bennett and southwest shoreline) at San 

Miguel Island, California.
58

Figure 6. Mean number of California sea lion pups, non-pups, and total (pups + non-pups) 

counted (±1 SD) at areas of (A) San Miguel Island, (B) San Nicolas Island, (C) Santa Barbara

Island, and (D) San Clemente Island, California during July 2011-2015. Refer to Figure 3 for 

location of areas.
59

Figure 7. Mean number of California sea lion pups, non-pups, and total counted (±1 SD) at areas 

of (A) Santa Catalina Island, (B) Santa Rosa Island, (C) Santa Cruz Island, and (D) Anacapa 

Island, California during July 2011-2015. Only areas with sea lions are shown. Refer to Figure 

4 for location of areas.
60

Figure 8. Mean percentage distribution (±1 SD) of California sea lion pups, non-pups, and total

(pups + non-pups) counted at areas of (A) San Miguel Island, (B) San Nicolas Island, (C) Santa 

Barbara Island, and (D) San Clemente Island, California during July 2011-2015. Refer to Figure 

3 for location of areas.
61

Figure 9. Mean number of northern elephant seals counted (±1 SD) at areas of (A) San Miguel 

Island and (B) San Nicolas Island, California during July 2011-2015; and (C) number of northern 

elephant seals counted at areas of Santa Rosa Island, California in July 2015 (only areas with 

seals are shown for Santa Rosa Island). Refer to Figures 3 and 4 for location of areas.
62

Figure 10. Mean percentage (±1 SD) of northern elephant seals counted at areas of (A) San 

Miguel Island and (B) San Nicolas Island, California during July 2011-2015; and (C) percentage 

of northern elephant seals counted at areas of Santa Rosa Island, California in July 2015 (only 

areas with seals are shown for Santa Rosa Island). Refer to Figures 3 and 4 for location of areas.
63

Figure 11. Mean number of Pacific harbor seals counted (±1 SD) at areas of (A) San Miguel 

Island, (B) San Nicolas Island, and (C) Santa Barbara Island, California during July 2011-2015, 

and counts of Pacific harbor seals at areas of (D) San Clemente Island, California in July 2015. 

Refer to Figure 3 for location of areas.
64

Figure 12. Number of Pacific harbor seals counted at areas of (A) Santa Cruz Island and (B) 

Santa Rosa Island, California during July 2015. Only areas with seals are shown. Refer to 

Figure 4 for location of areas.