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A CENSUS OF THE
CALIFORNIA GRAY WHALE

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..vii

SPECIAL SCIENTIFIC REPOKT-FISHERIES Na 342

United States Department of the Interior, Fred A. Seaton, Secretary-
Fish and Wildlife Service, Arnie J. Suomela, Commissioner
Bureau of Commercial Fisheries, Donald L. McKernan, Director

A CENSUS OF THE CALIFORNIA GRAY WHALE

Raymond M. Gilmore
Formerly, Biologist, Marine Mammal Research

[Edited by Dale W. Rice]

United States Fish and Wildlife Service
Special Scientific Report: Fisheries No. 342

Washington, D. C.
May I960

HUMP

BLOWING

".* —

CRENULATIONS

Frontispiece: Identification features of the gray whale.
ii

CONTENTS

Page

Summary ^

Introduction ^

Objectives ^

Acknowledgments ^

Taxonomy and distribution of the gray whale 3

Taxonomy ^

Distribution 4

Distribution and migration of the California population 6

Summer range o

Bering -Chukchi area 6

California-Oregon area 6

Southward migration 7

Winter range 1

Areas of migrating and wandering 9

Calving areas 9

Northward migration 14

Behavior studies 15

Behavior during migration 15

Orientation to land 15

Daily cycle of observations 15

Social behavior 16

Behavior on the winter range 16

Outer and intermediate area 16

Inner nursery area 18

Reproduction and mortality 18

Reproduction 18

Mortality 18

History of the California gray whale population, 1850-1952 19

Shore census of the southward migration, 1952-53 to 1956-57 20

Methods 20

Areas 20

Procedure 21

Extrapolations 21

Results 22

Census of 1952-53 22

Census of 1953-54 22

Census of 1954-55 23

Census of 1955-56 23

Census of 1956-57 23

Summary of shore censuses 23

Aerial surveys of the wintering grounds, 1952-57 25

Methods 25

Areas 25

Procedure 25

Results 26

Survey of 1 952 26

Survey of 1953 26

Survey of 1954 28

Survey of 1955 28

Survey of 1956 28

Survey of 1957 28

Summary of aerial surveys 29

Literature cited 29

Page

FIGURES

Frontispiece: Identification features of the gray whale ii

1. Distribution of the gray whale 5

2. Migratory routes of the gray whale (southern part) 8

3. Daily counts and extrapolations of gray whales passing San Diego during

the southward migration, 1954-55 9

4. Gray whale winter grounds 10

5. Northern area of migrating and wandering 11

6. Vizcaino area of migrating and wandering 11

7. San Juanico area of migrating and wandering 11

8. Cabo San Lucas area of migrating and wandering 11

9. Former San Diego calving area 12

10. Vizcaino -Scammon calving area 13

11. San Ignacio calving area 13

12. Magdalena calving area (northern part) 13

13. Magdalena calving area (southern part) 13

14. Yavaros calving area 14

15. Reforma calving area 14

TABLES

1. Frequency distribution of group size of gray whales during the south-

ward migration past San Diego 17

2. Frequency distribution of group size of gray whales on the breeding

ground 18

3. Counts and extrapolations of gray whales passing San Diego, California,

during daylight hours, 1956-57 24

4. Summary of shore censuses of gray whales in southward migration,

1952-53 to 1956-57 25

5. Summary of air censuses of gray whales on winter range, 1952-57 .... 27

SUMMARY

Gray v/hsil e s, Eschrichtius gibhosus
(Erxleben) 1777, were originally three
isolated stocks, termed the Atlantic,
California, and Korean populations.
The Atlantic population has long been
extinct; the Korean population has been
severely reduced in numbers. The
present study concerns only the Cali-
fornia population.

Most California gray whales spend
the summer (June through September)
in the northwestern Bering Sea and
the Chukchi Sea. A few summer along
the coast of northern California and
southern Oregon.

The southward migrating whales
strike the Pacific coast of North
America between Vancouver Island
and San Francisco. They then travel
within about 4 miles of the shore
until they reach Baja California. A
few are believed to leave the coast
at Point Conception, moving past the
offshore side of the Channel Islands
before striking the coast again south
of San Diego. Most southbound whales
pass San Diego between the middle
of December and the middle of Feb-
ruary.

In winter (early January to the end
of February) gray whales are scat-
tered along the Pacific coast from
about San Diego to Cabo San Lucas,
and in the southern end of the Gulf
of California. A few stragglers have
been observed in the northern Gulf
and at Guadalupe and Clarion Islands
as well as at various points as far
north as the coast of British Columbia.

Calving takes place in shallow la-
goons, bays, and esteros. The five
important calving areas are: (1) Viz-
caino-Scammon; (2) San Ignacio and
(3) Magdalena, along the Pacific Coast
of Baja California; and (4) Yavaros
and (5) Reforma, on the east shore of

the Gulf of California. San Diego Bay,
California, is no longer a calving
area.

The northbound migrants pass San
Diego mainly in March and April.
They move along the coast, and many
pass the west side of Vancouver Island
before turning off into the North Pacific,

The rate of migration is fairly uni-
form throughout the day. Movement
apparently is slightly greater in the
afternoon, when the fog tends to lift.
No data are available on rate of mi-
gration at night. For census purposes,
movement at night is held to be 50
percent of the daylight rate of 4 knots.

Gray whales are not strongly gre-
garious during migration. They usu-
ally travel singly or in groups of two
or three. Singles, presumably pregnant
females, are common in the early
stages of the southward migration.

Immature individuals and nonbreed-
ing adults predominate in the outer
channels near the entrances of breed-
ing lagoons; pairs and trios of courting
adults predpminate in the intermediate
areas, and cows with calves predomi-
nate in the inner "nursery" areas.

Adult cows bear one calf at 2 -year
(or longer) intervals. Gestation ap-
parently lasts 11 to 12 months.

Ehiring a 4 -season study in Laguna
Scammon, 12 dead calves and 2 dead
adults were found. The mean length
of 7 calves, measured in January and
February, was 13.25 feet.

From 1850 to 1890, whaling opera-
tions along the coast of California and
Baja California reduced the California
gray-whale population of 25,000 to
50,000 to perhaps a few thousand.
From 1890 to 1924, the population

increased. From 1924 to 1937, whaling
was again carried on. Since 1937, the
species has had complete legal pro-
tection.

Counts of gray whales during their
southward migration past San Diego,
in the seasons 1952-53 through 1956-
57, suggest that the population is in-
creasing, possibly as much as 10
percent a year. The estimated popu-
lation, including corrections for whales
passing unseen during periods of dark-
ness and poor visibility, and whales

passing offshore, was 2,894 in 1952-53
and 4,454 in 1956-57.

Aerial censuses of the winter range
indicate the extent of the breeding
grounds and their relative use by
whales. The most important areas
are: (1) Vizcaino -Scammon, with 1 ,500
to 2,000 whales (about half the total
population); (2) San Ignacio, with about
500 whales (one -eighth to one-sixth the
total population); and (3) Magdalena,
with 1,000 to 1,500 whales (about one-
third the total population).

A CENSUS OF THE CALIFORNIA GRAY WHALE

INTRODUCTION

OBJECTIVES

The main objectives of this study
have been ( 1 ) to estimate the size
of the total population and its pres-
ent rate of increase, (2) to deter-
mine the extent of the breeding
grounds and their relative impor-
tance, (3) to determine the time and
nature of the southward migration
past California, and (4) to establish
a basis for detecting, in the future,
any unusual changes in population
size.

The study was carried on by the
author for five years. With minor
exceptions, biological information
based on specimens was not obtained.
The International Convention for the
Regulation of Whaling, which protects
the gray whale, provides for taking
scientific specimens. Exact informa-
tion on age and reproduction can be
obtained in the future from specimens.
Observations in Bering and Chukchi
Seas will be needed to provide infor-
mation on food habits as well as
refinements in knowledge of migration
routes.

ACKNOWLEDGMENTS

The help of the following individuals
is gratefully acknowledged: G. Bara-
cott, Patricia Barton, O. Beasley, J.
Berdegue', D. Brown, C. Caito, C.
Chamberlain, W. Clinkscales, R.
Coughlin, Mr. and Mrs. D. E. Day,
L. Dean, D. Douglas, G. C. Ewing,
L. Farrar, A, Flechsig, R. Grom,
D. Hall, W. Hapgood, W. Harder, K.
Harris, E. Hess, R. Hoffman, A.
Hourston, C. L. Hubbs, J. Isaacs, J.
Jenks, S. Jewell, A. Kelly, R. L. King,
R. Lankford, D. Lear, C. Limbaugh,
J. McFall, R. Menzies, R. Meryman,
J. H. Millard, D. Miller, Madeline
Miller, Gladys Niebur, F. Nolan, K.
Norris, Grace Orton, F. Phleger, G. C.
Pike, A, B. Rechnitzer, D. Robinson,
A. Rodriguez, W. E. Schevill, M. Shear-
son, J, Snodgrass, J. Stackleberg, H.
Stewart, C. Tuthill, S. Z. Varnes, A. M.
Vrooman, T. Walker, P. D. White,
J. Whitehead, and T. Widrig.

Special thanks are due to C. L. Hubbs
and G. C. Ewing, both of Scripps Insti-
tution of Oceanography. The contribu-
tions of these two will be explained in
the text.

TAXONOMY AND DISTRIBUTION OF THE GRAY WHALE

TAXONOMY

The scientific name of the gray
whale has been changed several times
in the past 30 years. The living species
commonly called the gray whale was
long known by the specific name Agaphelas
glaucus, given by Cope (1868). Later
(1869) Cope placed the species ^Zaucus
in the new genus Rhachianectes. Rhachia-
nectes glaucus means "the gray swimmer

along the rocky shore," and a more
fitting name hardly could have been
coined. However, a prior name existed
which would eventually be recognized
to include glaucus and by the interna-
tionally recognized rule of priority,
Rhachianectes has been superseded. To
Tomilin (1957), Cope's name for the
living gray whales of the Pacific is
antedated by the name Balaena agamachschik
Pallas, 1811.

In 1937, subfossil bones of gray
whales, believed identical with the
living species, were described in de-
tail by van Deinse and Junge, from
Recent deposits in the drained polders
of the Zuider Zee, Holland, These
investigators identified earlier -de-
scribed fossils from Sweden and
England, which possess names that
antedate glaucus, as those of the living
species of gray whale.

One of these early names for a fossil
gray whale from Gras6, Sweden, in
the Gulf of Bothnia, was Balaenoptera robusta
Lilljeborg, 1861. Three years later
Gray (1864) set up a subgenus Eschrichtius
with robusta as type species. Later
(1865), Gray raised Eschrichtius to ge-
neric rank, and Lilljeborg followed
suit, calling the Graso whale Eschrichtius
robustus.

Van Deinse and Junge, however,
discovered an even earlier name,
Balaena gibbosa Erxleben, Mil, based on
the "scrag" whale of New England
origin and first mentioned by Dudley
in 1725 with a description suspiciously
like the gray whale, which stated, "A
Scrag Whale. Is near akin to the Fin-back,
but instead of a fin upon its back is
scragged with half a dozen knobs or
knuckles. He is nearest the Right
Whale in figure and quantity of oil.
His bone [whalebone] is white but wont
split." Van Deinse and Junge applied
the name Eschrichtius gibbosus to all popu-
lations of gray whale, living and ex-
tinct, thus assuming that the gray
whale lived on the New England coast
in the 18th Century. The gray whale
has never been known, either from
other reports or from specimens, to
inhabit the entire western North At-
lantic .

This action proved too much for
Schevill ( 1 954), who termed the "scrag"
whale and its name gibbosa a "literary
curiosity." In a neat turn of logic, he
stated that if the fossil gray whales
could not be shown different from the
living form, as stated by van Deinse
and Junge, then, neither could they
be shown identical, presumably because
soft parts were not examined and
complete fossil skeletons were not

available. Schevill thereby held Eschrich-
tius robustus to be the proper name for
the fossil specimens from the north-
eastern Atlantic, and E. glaucus for the
living form of the Pacific. In this he
was followed by Miller and Kellogg
(1955).

Such reasoning can lead only to
taxonomic chaos. Until nnorphological
differences have been demonstrated
between the extinct Atlantic and the
living Pacific populations, a single
name must be applied to all popula-
tions. It is unlikely that the populations
were miore than subspecifically dis-
tinct, at most. At any rate, the name
glaucus Cope would be invalid for the
Pacific populations because the name
agamachschik Pallas has priority.

The name Eschrichtius gibbosus Erxle-
ben, \in , has been adopted by most
recent authors (e.g., Cederlund 1939;
Ellerman and Morrison-Scott 1951;
Tomilin 1957; Slijper 1958). Although
this name rests on a somewhat debat-
able basis, it is used by the present
writer. If this name were rejected,
the correct name would become fscAric^.-
tius agamachschik Pallas, 1811. Such ac-
tion would be unfortunate as Pallas'
name was overlooked for many years
and has never been used by other
authors.

DISTRIBUTION

There are two distinct populations
of living gray whales: one known as
the California population, in the eastern
North Pacific; the other, known as the
Korean population, in the western North
Pacific. A third population, now ex-
tinct, occupied the eastern North At-
lantic (fig. 1 ).

There is some evidence that the
two Pacific populations have not mixed
in the 20th Century (Andrews, 1914).
Zenkovich (1934) believed that the east
coast of Kamchatka was, in his time,
unoccupied by gray whales in summer
and constituted a large unbridged gap
between the respective summer ranges.
Risting (1928), however, reported a
catch of gray whales made on the east

Figure 1.— Distribution of gray whale.

coast of Kamchatka. Thirty -one whales
(19 males, 12 females) taken from
July 27 to August 22, 1925, with Na-
thalia Bay as a base, ranged from
25 to 36 feet in length. This was a
smaller and younger group of whales
than was taken by the same vessel
from Bahfa Magdalena, Mexico. Risting
believed they had migrated from Mexi-
can, rather than Korean, breeding
grounds. Sleptsov (1955) stated that
the populations "probably nnixed before
each herd was reduced to very low
figures."

Distribution and migration of the
California population will be discussed
in detail in the next chapter.

Gray whales of the Korean popula-
tion spend the summer in Okhotsk Sea.
The same whales were reported by
Scammon (1874), Andrews (1914), and
Mizue (1951) to spend the winter in
the waters of South Korea, and per-
haps the Yellow Sea. These whales
apparently calve in the channels, in-

lets, and bays along the rocky coast
of South Korea.

Fraser (1937) reported that gray
whales were taken with nets by the
Japanese as far back as the 17th
century, but the harvest was unim-
portant. After 1903, gray whales were
captured in unrestricted numbers by
modern whaling equipment and by 1938
the population was so low that all
further whaling ceased because it was
unprofitable. There are no estimates
of the number remaining when whaling
stopped.

Subfossil remains of gray whales of
the Atlantic population have been un-
earthed from Recent deposits at three
localities in Europe: (1) Grisd, Swe-
den; (2) Cornwall and Devon, England;
and (3) Zuider Zee, Holland (van Deinse
and Junge 1937). The gray whale ap-
parently survived into historical times
off the coast of New England, where
it was captured by early 18th century
whalers under the name "scrag" whale
(Dudley, 1725).

DISTRIBUTION AND MIGRATION OF
THE CALIFORNIA POPULATION

SUMMER RANGE

Most California gray whales appar-
ently spend the summer in the Arctic --
in the Bering and Chukchi seas. No
gray whales have ever been followed
from one ground to the other, nor
marked in one area and recovered in
the other. However, the times of dis-
appearance and reappearance of gray
whales in the winter grounds off Baja
California and in the summer Arctic
grounds, along with the direction of
movement, lead to the assumption that
these whales are of the same herd.
A few have recently been found in
summer on the coast of northern Cali-
fornia and southern Oregon.

cording to Zenkovich ( 1 934) and Sleptsov
(1955), gray whales arrive in north-
western Bering Sea and Chukchi Sea
in June and stay through September,
Ichihara (1958) reported a single gray
whale in Unimak Pass on May 29,
1957, and another seen from a whale
catcher on July 28, west of St. Law-
rence Island. Also, on August 2, be-
tween 63034'N., 172°48'W. and 63°
54'N,, 170°50'W. (west of St. Lawrence
Island) three groups consisting of 3,
20, and about 150 gray whales, 36 to
41 feet in length, were seen and photo-
graphed by Keiji Nasu of the Whales
Research Institute. The larger ag-
gregations were divided into smaller
groups of one to three whales.

Bering-Chukchi Area

No studies of gray whales were con-
ducted in the Bering -Chukchi area
during the present investigations. Ac-

California -Oregon Area

A whaling company operating out of
Humboldt Bay, California, in the 1940's,
found a small herd of gray whales

spending the summer around Crescent
City, St. George Reef, and Pelican
Bay, Oregon, 75 to 100 miles north
of Humboldt Bay. In September 1947
and June 1948, the writer saw 12 to
15 gray whales in Pelican Bay.

SOUTHWARD MIGRATION

California gray whales, in the course
of their southward migration, are as-
sumed to move across the open waters
of the North Pacific from the vicinity
of the Aleutian Islands to the coast of
the United States. They reach the
coast at points well north of San Diego,
and even north of San Francisco. Gor-
don C. Pike (in lit.) has stated that
south-migrating gray whales strike
the North American coast at a point
south of Vancouver Island. Most of
them travel close to shore. The main
migratory path is several miles wide
and usually within one to three miles
from shore. Gray whales have not
been recorded migrating south at sea,
far off the coast of southern Cali-
fornia or off Baja California (figs.
1 and 2).

However, some gray whales do mi-
grate southward offshore, since they
have been seen at Isla Guadalupe and
Isla Clarion. The route used in reach-
ing these islands is not known. It has
been suggested, with little factual
basis, that the same whales may move
along the Santa Barbara (or Channel)
Islands, San Miguel, Santa Rosa, Santa
Cruz, Santa Barbara, Santa Catalina,
and San Clemente. Gray whales have
been seen approaching land at La Jolla,
and off the Coronado Islands, 12 miles
south of Point Loma. Others have
been seen from aircraft, making their
way southward toward the mainland
from the tip of San Clemente Island.
Records of offshore movements are
so few that any attempt to outline
routes must be largely speculative.

Southbound gray whales are usually
seen at San Diego during the latter
half of November, though not com-
monly until after the middle of De-
cember. The bulk of the population
passes in January, mainly during the

middle two weeks of the month. By
mid -February, the southward migra-
tion is virtually over, although a few
stragglers have been seen moving
south as late as March 25.

The intensity and duration of the
southward migration are illustrated
in figure 3. Here are shown the num-
ber of whales counted daily at San
Diego, with extrapolation for whales
passing unseen during the day because
of bad weather, during the period from
December 19, 1954, to February 15,
1955. (In preparing this figure, no
extrapolation was made for whales
passing unseen at night. See page 21.)
Earlier, from November 19 to Decem-
ber 18, 28 whales were seen and
another 56 estimated, or a total of 84.
Later, from February 16 to 28, 8
whales were seen and another 8 esti-
mated, or a total of 16. The whaling
vessel Vega (Risting 1928) began whal-
ing on November 14, 1924, in Bahia
Magdalena but took only humpback
whales until December 27, when the
first gray whale was captured. In 1925
and 1926, the first gray whales were
taken on December 29 and December
28, respectively. Migrants began to
arrive regularly on January 4, the
migration reached its height on Jan-
uary 22, and the last whale was taken
on February 16. The first arrivals
were pregnant females. Males gradu-
ally became numerous in January.
Gray whales (82) taken here ranged
from 30 to 42 feet in length.

WINTER RANGE

From early January to the end of
February, the California gray whale
population is concentrated in the
coastal area from about San Diego
southeast to Cabo San Lucas and the
southern end of the Gulf of California.
For convenience, the winter range
may be divided into ( 1 ) migrating and
wandering areas which are utilized by
nonbreeding whales and by whales en
route to more southern parts of the
winter range, and (2) calving areas,
utilized by whales for mating and
calving (fig. 4).

Figure 2.~Migratory routes of the gray whale (southern part).

^ WHALES COUNTED

EEl EXTRAPOLATION FOR

WHALES UNSEEN

Figure 3.— Daily counts and extrapolations of gray
whales passing San Diego during the southward mi-
gration, 1954-55.

Areas of Migrating and Wandering

For census purposes, areas of mi-
grating and wandering have been broken
down as follows:

Northern area. --The northern area
extends for 350 miles from San Diego
along the west coast of northern Baja
California to Punta Santo Domingo, at
the northeast periphery of the huge, open
Bahia de Sebastian Vizcaino (fig. 5).

Vizcaino area. --The Vizcaino area
extends from Punta Malarrimo on the
south shore of Bahia de Sebastian
Vizcaino, not far from Laguna Scam-
mon, west and then south around the
Peninsula de Vizcaino to Punta Abreo-
jos at the northern end of Bahia
Ballenas, near Lagiina San Ignacio.
A few gray whales were seen at Isla
de Cedros and the Benitos, 30 miles
northwest. Bahia San Bartolome was
never seen occupied by gray whales
during the period of the censuses
(fig. 6).

San Juanico area. - -A 75 -mile stretch
of low, sandy coast extends from Boca
Querante to Boca Las Animas, and
includes the important open bay, or
bight, of San Juanico. No whales were
seen within the small, but apparently
deep Laguna San Gregorio at any time
during the censuses. Cows and calves
were seen in Bahia San Juanico and
it was possible that the calves were

born there, although the area was not
considered a true calving ground (fig.
7).

Cabo San Lucas area. --The large
Cabo San Lucas area comprises the
entire coastline of the "Cape Area"
of the Peninsula of Baja California,
from Boca Santa Marina to near La
Paz, around Cabo San Lucas. Before
the discovery of calving grounds in
the Gulf in February 1954, whales
seen in this area were thought to be
nonbreeding wanderers, but it is real-
ized now that the gray whales seen in
the Cape area were, at least in part,
migrants to and from the Gulf (fig. 8),

Extralimital areas. --Gray whales
were observed a number of times in
winter outside their normal range,
in the Gulf of California and near
offshore islands in the Pacific.

In the Gulf, north of the regularly
used La Paz and Y^varos areas, 10
gray whales have been seen (1) four
adults at Canal San Lorenzo near
La Paz; (2) a cow and calf at Bahia
Concepcidn, 250 miles north on the
east side of the Gulf; (3) two adults,
slightly north of Santa Rosalia; (4) one
adult, 100 miles north of Santa Rosalia;
and (5) one adult at Punta Final, 500
miles north of Cabo San Lucas, on
the east side of the Gulf.

In the Pacific, gray whales have
been seen at Isla Guadalupe, 125 miles
off northern Baja California, and at
Isla Clarion, the westernmost island
of the Revilla Gigedo group, 375 miles
southwest of Cabo San Lticas. One
whale was seen within 100 yards of
the beach of the northeast bay on
Isla Guadalupe, on February 15, 1957,
by Arthur Flechsig, zoologist from
Scripps Institution of Oceanography.
On March 13, 1957, Daniel Brown,
also from Scripps, saw 1 5 gray whales,
4 of which were calves, at the south-
west end of Isla Clari<4n.

Calving Areas

The female California gray whale
normally resorts to lagoons, bays.

Figure 4.— Gray whale winter grounds.

ISLA DE
SAN BENITO "^ XeBASTIAN VlZCAINo/

LAGUNA GUERRERO
NEGRO

SALT CAMP

LAGUNA
SCAMMON

<■■"■ ABREOJOS

115°

Figure 5.--Northem area of migrating and wandering. figure 6.-- Vizcaino area of migrating and wandering.

\t_A^ BAHIA

\ ri ISLA OE
\ B.MIA V»^

nAPAZ^"'^

PARTI OA
5»NL0«Nl°

YL ISL* OE CEHRALVO

^^A PAZ

Un /''

^^a^'MgCENTES

BUENA ^'^W^ ^
VISTA " - ■^^Vi ^

h\ /

NTOS I )t '

N JOSE -J
EL CkBO ^^^^y'

•

CABO SAN LUCAS

Figure 8.— Cabo San Lucas area of migrating and
wandering.

Figure 7.— San Juanico area of migrating and
wandering.

and esteros* to bear her calf. Occa-
sionally, calves are born in shallow,
open water close to shore. Calving
occurs, or formerly occurred, in six
general areas: (1) San Diego (aban-
doned), (2) Vizcaino -Scammon, (3) San
Ignacio, (4) Magdalena, along the Pa-
cific Coast of southern California and
Baja California, (5) Yivaros, and
(6) Reforma, along the east shore of
the Gulf of California in the states of
Sonora and Sinaloa (figs. 2 and 4).

San Diego area. --Gray whales used
to breed in large numbers in San
Diego Bay, but these were largely
exterminated by two whaling stations
at the entrance in the 1850's, 1860's,
and 1870's. Subsequently, boat traffic,
water pollution, and harbor improve-
ments have effectively prevented re-
occupation. However, gray whales
occasionally calve, and more often
mate, in open waters just outside the
bay. A lobster fisherman, visiting his
pots in kelp beds south of La Jolla in
January 1955, saw "many times'* a
gray whale cow and calf. This account
was recorded by Carr Tuthill of the
aquarium of Scripps Institution of
Oceanography. During the 1955-56
season, two calves were bornin waters
off the San Diego area (fig. 9).

Two bays in northern Baja Cali-
fornia, Bahia de Todos Santos (in-
cluding Estero de Punta Banda) near
Ensenada, and Bahia San Quintin, near
San Quintin, also appear to be suitable
as calving areas for gray whales. No
whales were seen in either bay. Gray
whales surely inhabited both areas,
although no historical evidence to this
effect has been uncovered (fig. 5).

Vizcaino -Scammon area. --The Viz-
caino-Scammon area includes ( 1 ) the
shoreline of Bahia Vizcaino from Punta
Santo Domingo to Punta Malarrimo,
(2) Laguna Guerrero Negro, and

lAn estero is a long, narrow body of water parallel to
the coast and separated from the sea by a barrier beach.
A channel between an estero and the sea is a boca. A
lagoon (lagunaj, as the term is used here, is a large body
of water which extends several miles inland and is par-
tially cut off from the sea by a bar across its mouth. A
bay (bahia) is a marked indentation of the coastline not
usually separated from the sea.

Figure 9. --Former San Diego calving area.

(3) Laguna Scammon. It includes about
30 miles of coastline and bars, and
100 to 200 square miles of channels
navigable by gray whales, in Laguna
Guerrero Negro and Laguna Scammon.
Laguna Manuela was not occupied by
gray whales during the period of the
censuses (fig. 10).

San Ignacio area. --Included in the
San Ignacio area are (1) the open bight
of Bahia Ballenas; (2) the large and
important Laguna San Ignacio; and
(3) the small, as yet unnamed, lagoon
farther south, called here "Laguna
Querante" (from a nearby ranch so
marked on the U. S. Navy hydrographic
chart 1493, based on surveys made in
1890-95). Perhaps 30 to 50 square
miles of lagoon channels are navi-
gable to the gray whale in San Ignacio
and Querante. Gray whales were never
seen in Laguna Coyote during the
censuses (fig. 11).

Magdalena area.- -A distinct calving
and mating ground, the Magdalena area

Figure 10.--Vizcarno-Scammon calving area.

Figure 11. --San Ignacio calving area.

includes (l)the long esteros (Las
Animas, Santo Domingo, and Soledad)
north of Bahia Magdalena, parallel to
the ocean beach but separated from
the ocean by a continuous sand barrier
with three bocas, (2) the upper reaches
of the bay, such as Canal San Carlos,
(3) the wide and deep Bahia Magdalena
itself, and (4) Bahia Almejas, the south
arm of Bahia Magdalena. This entire
area includes 130 miles of low or

rocky coast, and also sonne 200 to 2 50
square miles of esteros, lagoons, and
bays accessible to the gray whale
(figs. 12 and 13).

Figure 12.— Magdalena calving area (northern part).

Figure 13. —Magdalena calving area (southern part).

In the 19th century, the enormous
and complex Magdalena area was
probably the principal breeding ground
of the California gray whale. However,
because its central waters were ac-
cessible to sailing ships and its shal-
lower tributaries to whaleboats, its
whale population was soon exploited.
From 1952 through 1957, boat traffic
was often seen in the main bay. Gray
whales consorted in numbers only in
the more inaccessible tributaries.

Yavaros area. --In February 1953,
an aerial survey of the Yavaros area
disclosed breeding grounds at Yavaros
and Bahia Refornna, on the eastern
side of the Gulf of California. Whales
had never before been found here,
even by early whalers.

The Yavaros area is about 6 to 8
miles south of the port and bay of
Yavaros, Sonora. It seems to have
no distinctive feature which would
attract gray whales. The water is only
2 to 5 fathoms deep. The whales
observed were from 200 to 800 yards
from the beach, leaving mud trails
behind them as they swam in waters
believed to be as shallow as 2 fathonns
(fig. 14).

There are perhaps 10 to 20 square
miles of lagoon in the northern part
well suited to gray whales (fig. 15).

Figure 14.~Yavaros calving area.

Reforma area.--Bahia Reforma is a
huge lagoon-like bay 120 nautical miles
southeast of Yavaros, in the State of
Sinaloa. It is about 35 miles long and
is navigable by whales and small boats.

Figure 15.— Reforma calving area.

NORTHWARD MIGRATION

The northward migration first passes
San Diego in mid -February, is in full
swing in March and April, and tapers
off in early May. Gray whales going
north seem to veer off the coast at
Point Loma, passing La Jolla several
miles at sea, as though on direct
course across the great bight of the
coast of southern California from San
Diego to Palos Verdes Peninsula.
Because movement apparently is away
from the coast, it does not seem
possible to count the migration north
with the same accuracy possible for
the southward migration. From Palos
Verdes Peninsula, most whales mi-
grate parallel to the coast on their
way north.

Vessels engaged in fur-seal research
for the Bureau of Commercial Fish-
eries, in 1958 and 1959, sighted gray
whales during March from 36°46'N.
in Monterey Bay to 41°23'N. off
Gold Bluffs, California. April obser-
vations ranged from 40°47'N. off the
Eel River in California to 47°54'N.
off James Island, Washington. On April

24, 1959f personnel on the vessel
Tacoma saw more than 200 gray whales
from about 19 miles off Destruction
Island to near James Island. On that
day they saw a bloated, dead gray
whale rise to the surface. On April
25 the vessel ran out of the gray-whale
concentration 9 miles off James Island
(C. H. Fiscus, T. C. Juelson, and
K. Niggol, in lit.). Observers on the
Canadian research vessel Pacific Ocean
saw gray whales off Cape Flattery,
Washington during the last 2 weeks
in May (Gordon C. Pike, in lit.).

Annually, large numbers of whales
concentrate close to the west shore
of Vancouver Island in March and
April, many passing through the mile-
wide channel between Solander Island
and Cape Cook on the northern part
of Vancouver Island. After passing
along the west coast of Vancouver

Island, the whales disappear in a
westerly direction into the North
Pacific Ocean. As late as May 17,
1959, gray whales were observed off
the north end of Vancouver Island
by whalers from the station at Coal
Harbour, Quatsino Sound.

Nine gray whales were taken for
scientific purposes in April 1952 from
the station at Coal Harbour under
special permit issued in accordance
with the provisions of the International
Convention for the Regulation of Whal-
ing. Northward migrating whales were
too thin to be of commercial value.

Eight gray whales, in pairs, were
seen on May 11, 1957, moving very
close to the kelp between Kodiak and
Ugak Islands toward Narrow Cape,
Alaska (F. Wilke, in lit.).

BEHAVIOR STUDIES

BEHAVIOR' DURING MIGRATION

Actions which will enable them to
arrive quickly at the breeding grounds
seem completely to dominate the be-
havior of gray whales as they swim
past San Diego. They do not wander
or feed. Occasionally, whales stop
and attempt to court or mate, but even
these rarely stay long or wander from
the migration route.

Orientation to Land

Close adherence to the coasts of
southern California and Baja Cali-
fornia is an outstanding feature of
their migratory behavior. The herd
passes along the coast, skirting head-
lands and sometimes cutting across
bays, generally remaining within three
miles from shore. Such behavior must
help them find the entrance of shallow
bays and lagoons for calving and mat-
ing.

A gray whale will often thrust its
head completely out of the water,
almost to the flippers, and hold it out
for about 10 seconds. Or when "blow-

ing" at the surface, the whale will
merely raise its head out as far as
the eyes. Subsequently, the whale's
movennents will suggest reorientation
based on visual stimuli. Gray whales
sometimes follow the walls of deep
submarine canyons in La JoUa Bay
instead of the shoreline. This suggests
that they may be following, in pref-
erence to the coast, a bottom contour
of 100 to 150 feet depth.

The extent to which vision may aid
navigation along the shore, nor the
extent to which darkness may slow
travel, could not be measured. Fog is
believed by some observers to slow
travel but this has not been proved.

Daily Cycle of Observations

During a count in 1954-55 from
Point Loma, sightings of 1,319 whales
were recorded by hour of day. For
each consecutive hour between 7 a. m.
and 5 p. m., the following number of
sightings was recorded: 50, 145, 113,
103, 134, 99 (noon to 1 p. m.), 156,
189, 175, 155. The higher figures of
afternoon are probably the result of

improved visibility --lifting of haze.
The low values at 7 a. m. and noon
may (?) represent human errors of
some kind.

Increased visibility in late afternoon
was demonstrated again in 1956-57,
when the count of whales at La JoUa-
Scripps from 3 p. m. to 5 p. m.
equalled 29 percent of the count at Point
Loma from 7 a. m. to 5 p. m. (2 hours
against 10). Had whales been observed
at the same rate for the 2 hours as
for 10 hours, the proportion would
have been one -fifth or 20 percent.

Social Behavior

Gray whales, like most large whales,
travel singly or in small groups. The
frequency distribution of groups in the
1952-53, 1954-55, and 1956-57 seasons
is given in table 1 . Single animals
predominate in November and Decem-
ber. These are mostly large individ-
uals, presumably pregnant females,
traveling alone to the lagoons and
bays to calve, and presumably not
physiologically ready to mate. Most
single animals, traveling later, are
thought to be adult males, nonbreeding
females, or yearlings. Little is known
about differences in migratory behav-
ior according to age and sex.

Groups of two and three are com-
monest in January. At that time, the
animals are mating or courting en
route. Groups of three would perhaps
most logically be composed of two
males and one female. (See section,
below, on behavior on the winter
range.) Groups of four perhaps include
three males and one female, or two
pairs joined by coincidence. Pregnant
females are probably solitary, as are
the yearlings not yet integrated into
social groupings.

BEHAVIOR ON THE WINTER RANGE

Some observations of behavior were
made during the aerial census, when
animals were seen on the breeding
and calving grounds and wandering

nearby. Most behavior studies, how-
ever, were made at close range from
small boats propelled among the
whales during special visits to the
breeding lagoons.

Behavior studies on the winter
range were made at Estero Las Ani-
naas on February 22, 1953, and at
Laguna Scammon on February 17-25,
1954, February 4-14, 1955, January
25 to February 8, 1956, and February
9-18, 1957.

In and near the breeding lagoons,
gray whales appear to be segregated
by age, sex, and reproductive condi-
tion.

Outer and Intermediate Area

Most whales seen outside the en-
trances of lagoons are evidently idle
adults, courting adults, or imnnatures.
No calves and no recently parturient
females are found here.

The intermediate area consists of
channels within the entrance. Many
nuptial groups, some cows and their
newborn calves, and some wandering
singles are found in these locations.
Mating and courting is done between
adults without calves present. Pairs
of courting adults are the commonest
reproductive group, but groups of three
are also common. On one occasion,
three adults were identified by copu-
latory activity as a female, a dominant
male, and probably a complemental
male. The sex of the latter was not
definitely ascertained, but its nervous,
"sideline" participation suggested that
it was a male. (If only half the females
breed each year, as the author sus-
pects, and if the sex ratio is 50 : 50,
there will be twice as many eligible
males as females on the breeding
grounds.) Breeding pairs and trios
are most contimon near the outer en-
trance of the lagoon but also penetrate
the lagoon to its very head, and are
observed outside the lagoon. Segrega-
tion of courting groups and cows with
calves is more distinct in the Mag-
dalena area than in the Scammon area.

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In the Magdalena area, courting groups
are confined mainly to the outer waters,
and cows with calves to inner waters.

Inner Nursery Area

Most cows with calves retreat far
into the lagoon, although sonne occupy
the area in and around the entrance.
Cows and their calves gather in great
numbers in Laguna Scammon, 20 to 30
miles from the entrance. Some court-
ing pairs and a few trios may also
be seen here in the upper end. A cow

and her calf are rarely seen with
other whales. No cow with calf was
seen engaged in mating, although on
two occasions a cow with calf was seen
swimming in company with another
adult.

The count of whales during a trav-
erse of the three areas in Laguna
Scammon on January 25 and 26, 1956,
gives a quantitative idea of the distri-
bution of the groups. A total for the
entire 15 -day trip would be misleading
because the length of time spent in
the three areas differed (table 2),

TABLE 2.— FREQUENCY DISTRIBUTION OF GROUP SIZE OF GRAY WHALES ON BREEDING GROUNDS

Composition of group

Frequency

Outside bar

Intermediate

Inner nursery

and channel

area

10+

Single adult . . .

Two adults

Three adults . . .
Cow with calf. .
Cow-calf -adult .
Four or more . . .

1 (coast)

REPRODUCTION AND MORTALITY

REPRODUCTION

Pregnant female gray whales taken
by the Vega (Risting, 1928) ranged
from 34 to 50 feet in length; mean
length of 23 such females was 37.3
feet. The maximum of 50 feet is 5
feet longer than given in other rec-
ords. Cows with newborn calves do
not engage in courtship activity. Evi-
dently, therefore, recently parturient
cows are not in estrus, and likely do
not come into estrus until the following
winter, after the calf has been weaned.
Reproduction may thus be biennial. If
so, it would follow that some females
each year bear young and nurse while
the others mate. Since copulation and

parturition are observed at the same
time of year, the gestation period must
be 11 to 12 months. Two females
killed on March 13 and 14, 1912, at
Chan Chien Dogo, Korea, each con-
tained a fetus, one 7 and one 10 inches
long. Nearly grown fetuses found in
females at Magdalena Bay were re-
ported by Risting (1928) as 16 to 17
feet long. These fetuses seem im-
probably long. The observed number
of new offspring with an adult was
always one.

MORTALITY

Mortality is thought to be high in
the newborn class but not in any other

age group. Twelve dead calves were
found in Laguna Scammon: 5 in 1954,
2 in 1956, and 5 in 1957. Measure-
ments of seven are as follows (length
in feet): 11.6, 12.0, 12.5, 13.4, 13.9,
14.7, 14.8; mean 13.25 feet. The sex
of only two carcasses was identified,
a male 12.0 feet and a male 14.7 feet.
The causes of death among calves are

not known. Presumably, as in other
mammals, congenital defects, failure
of the female to provide adequate milk,
and accidents cause some mortality
among the newborn.

During four seasons of study in
Laguna Scammon, only two dead adults
were found; both were stranded.

HISTORY OF THE CALIFORNIA GRAY WHALE
POPULATION, 1850-1952

Annually, fronri the 1850's to the
1890's, the California gray whale was
captured systematically in winter along
the coast of California and Baja Cali-
fornia from shore stations and from
whaling ships. Ships entered the la-
goons and harassed the cows with
calves, as well as the breeding adults.
Unrestricted whaling on the breeding
grounds reduced the herd from a high of
perhaps 25,000 to 50,000 to a low of a
few thousand animals (Gilmore, 1955).

Andrews (1914), as well as Howell
and Huey (1930), and Zenkovich (1934),
considered the gray whale headed for
extinction. The smiall, residual Cali-
fornia herd at the turn of the century
escaped detection by zoologists be-
cause no serious effort was made to
look for them.

From the 1890's to the early 1920's,
gray whales off California were rela-
tively unmolested. Shore operations
from Monterey and San Pedro were
small. A Norwegian factory ship hunted
for a time off Baja California. The
California herd was actually increas-
ing, though at a rate unknown. A. W.
Anthony (1921) reported that gray
whales were "common" off San Diego.

From 1924 through 1937, the Cali-
fornia gray whale was hunted in
southern California and Baja Califor-
nia during winter, and off northern
Kamchatka and in the Chukchi Sea
during summer. Throughout this pe-
riod, the gray whale was thought to
be scarce, numbering perhaps a few
hundred individuals. From 1935 to
1938, Karl W. Kenyon (in lit.) fre-
quently observed gray whales off
southern California and did not con-
sider the species scarce in that area.

In 1936 (to take effect in 1937) the
United States Government prohibited
the capture of gray whales by Ameri-
cans in American waters. In 1937 (to
take effect in 1938) the International
Convention for the Regulation of
Whaling, signed in London, gave the
gray whale complete protection over
its entire range.

In August 1940, before Japan be-
came a party to the Convention, Japa-
nese nationals took 58 gray whales
in Chukchi Sea and Bering Strait from
the floating factory Tonan Maru (original
records). Since 1947, unrecorded num-
bers, though certainly few, have been
captured by aborigines of the U.S.S.R.
off northern Kamchatka and the
Chukotsk Peninsula.

From 1946-47 to 1951-52, Dr. Carl
L. Hubbs estinnated the numbers of
gray whales migrating southward past
La Jo 11a by instituting a "whale -watch"
atop a classroom building at Scripps
Institution of Oceanography. The
whale -watch was maintained by volun-
teers about 15 minutes out of each
daylight hour. The total estimated day-
light migrations for the first six years
are as follows (unpublished notes by
courtesy of Dr. Hubbs):

1946-47 250 whales

1947-48 500

1948-49 600

1949-50 600

1950-51 no estimate

1951-52 880 whales

In December 1952, the Fish and
Wildlife Service began a study of the
California gray whale population. It
continued until the end of the 1956-57
season. (See objectives, page 3).

SHORE CENSUS OF THE SOUTHWARD MIGRATION,
1952-53 to 1956-57

METHODS

Areas

A satisfactory count of whales mi-
grating south can be made from three
points of vantage at San Diego. Two
were used routinely by the writer.
The first is the summit of Point Loma,
a ridge of land separating curved San
Diego Bay from the sea at its north-
west side. The southern end of Point
Loma faces southeast over the en-
trance to the bay and over the entire
length of coast extending south to
Mexico, 15 miles away. It also faces
the Pacific Ocean to the southwest,
west, and northwest, and the coastline
to La Jolla, 10 miles to the north.
The panoramic view over the Pacific
is about 200 degrees. The elevation
is 510 feet above sea level, which
allows an observer to see about 15
miles to the horizon. Water of 300-
foot depth lies 4 to 4-1/2 miles off-
shore. Kelp beds, marking approxi-
mately the 100-foot depth contour,
are less than 1-1/2 miles out. Thus,
whales can skirt the point closely and
can be observed easily.

Counts were conducted from a mili-
tary bunker partly buried in the sum-
mit of the western cliff on Point Loma.
The bunker gave shelter from the
elements, as well as a place to sit
and write, and it offered good visual
sweep of the Pacific Ocean. From
this location, two seasonal assistants
carried on a count of gray whales
migrating south. Point Loma ridge
is the site of Cabrillo National Monu-
ment, and one of the most popular
attractions here in winter is the whale
migration. During the study, the Na-
tional Park Service maintained a
"public whale -watch" with the aid of
the Superintendent Donald Robinson
and Ranger-Naturalists Theodore
Walker and Robert Grom. Many tour-
ists looking for whales joined the
watch daily and their presence helped
to alert the regular watchers to
"spouts."

The second point of vantage, used
by the writer, was atop a classroom
building at Scripps Institution of Ocea-
nography in La Jolla, 12 miles north
of Point Loma. This lookout post was
protected from the weather by a small,
wooden structure, and housed a pair
of 18 -power binoculars on a stand.
The slight curvature of the coast and
the westward prolongation of nearby
Point La Jolla for one mile, to form
the bay of La Jolla, put this observa-
tion post at a greater distance from
the center of the path of migrating
gray whales than Point Loma or Point
La Jolla. The low elevation of the
Scripps lookout, which is about 100
feet above sea level, obliges the
watcher to look through more haze
and to scan the sea at a lower angle,
making whale "slicks" more difficult
to see.

The fact that the location at Scripps
is two hours or slightly more, "as
the gray whale swims," from Point
Loma, allows addition to the Point
Loma count of the numbers of whales
that pass Scripps from 3 p. m. to 5
p. m. Part of these whales do not
arrive at Point Loma until after dark.
The hours of whale watching at Point
Loma are thus increased, in effect,
by two, from 10 hours to 12.

The third point of vantage in the
San Diego area is Point La Jolla
itself. From here, either from the
crest of the sea-cliff some 25 feet
above high-tide mark, or from any
road parapet nearby, gray whales may
be easily seen as they pass along the
outer edge of the kelp beds just off
the point. The kelp beds, which grow
on the rocky bottom, extend to the
100-foot depth contour not more than
800 yards from shore.

Gray whales come closer to land at
Point La Jolla than at either of the
other posts, and permit the clearest
and most exciting views of the ani-
mals. However, lack of shelter limits
the use of this point as a whale -
counting station.

Procedure

Whale counters were usually sta-
tioned at Point Loma, where each
counted for five hours daily, either
fronn 7 a, m. to noon, or from noon
to 5 p. m. These periods cover the 10
daylight hours of midwinter at the
latitude of San Diego, 32°45'N. Five
hours are about the limit of endurance
of one counter; a longer period pro-
duces observational fatigue.

Each counter was equipped with a
logbook, a pair of binoculars, and a
watch. Each time a whale, or group
of whales was sighted, the time, num-
ber of whales, and visibility were
recorded.

Identifying characters of the gray
whales, of use to the watchers, are
the length of 30 to 45 feet, color dark
gray or nearly black, blotched with
white marks of roughly circular or
irregular outline up to a foot in diam-
eter, absence of dorsal fin which is
replaced by a low, thick ridge followed
by a series of 8 to 12 small sharp
knuckles and a convex rostrum. The
dorsal ridge and series of knuckles
are the most characteristic and easily
observed diagnostic feature of the gray
whale. The flukes are often thrown
conspicuously in the air on a "sound-
ing" dive. Although of characteristic
shape with small tips and prominent
rear curve, the smallish flukes are
not always seen clearly.

Extrapolations

In virtually all wildlife censuses,
some individuals escape detection and
are not counted. In estimating the
whale population, the writer has added
corrections for whales which passed
(1) during bad weather in daytime with
poor or no visibility, (2) at night, and
(3) beyond sight of land.

Extrapolations for poor visibility. --
Daytime bad -weather extrapolation
was based on three points: (1) degree
of visibility; (2) abundance of whales,
i. e., intensity of migration at the
time; and (3) density of fog (when

reduced visibility was caused by fog)
because fog was assumed to slow the
rate of travel.

When visibility was not zero, and
some whales were seen close to shore,
extrapolation was based directly and
entirely upon the estimated degree of
reduced visibility. For example, if the
haze settled so heavily that visibility
was lowered to 1,000 yards, or 25
percent of normal, and 10 whales were
seen, the number estimated to have
passed unseen was 30, or a total of 40.

When rain or fog reduced visibility
to zero, the nearest period of clear
visibility was taken as a basis for
extrapolation. For example, if visi-
bility was completely blanked out by
fog in morning (7 a, m. to noon) and
the afternoon hours (noon to 5 p. m.)
were clear, and 25 whales were seen,
the extrapolation value for the morn-
ing was 25. Or, if there had been three
days of heavy fog with visibility zero,
the past previous day of good visibility
was taken as a basis for extrapolation.
If 50 whales had been seen on that day,
the extrapolated value for each of the
three foggy days would be 50,

Persistent foggy weather was be-
lieved to slow down travel of whales.
If three foggy days occurred in a row,
the extrapolation was weighted down-
ward by 40 percent; the extrapolation
was further reduced if the fog con-
tinued. (Here the writer freely admits
the possibility of fairly serious error.)

Extrapolation for night migration. --
Gray whales are known to migrate at
night. They are seen occasionally from
boats, though the speed of night travel
has never been learned. Nevertheless,
suppositions which lead the writer to
conclude that gray whales slow down
considerably at night are as follows:

Whales presumably have occa-
sional rest periods. As whales were
not seen sleeping in daytime, they
must do so, if at all, at night.

If dependence is upon vision (in
air) for close navigation of the
shore, and light of sun or moon is

required, then dark nights could
slow migration greatly.

Whales may have some irregular
feeding activities, particularly noc-
turnal, but no whales migrating in
the day were seen feeding off south-
ern California.

The distance from northwestern
Bering Sea to San Diego is about
6,000 miles. If a little less than
three months is postulated as a
reasonable time for swimming this
distance, and four knots is an aver-
age swimming speed, then a gray
whale could sleep seven hours in
each 24 -hour period.

On the basis of these suppositions,
and lacking accurate information,
50 percent of daytime movement
was used as an extrapolation for
night movement.

In making extrapolation for night
migration, two methods of dividing the
day into hours of daylight and dark-
ness are evident. The time of sunrise
and sunset from late December to
mid -February at La JoUa divide the
day into 1 0 to 10-1/2 hours of daylight
and 13-1/2 to 14 hours of darkness.
If the 7 a. m. to 5 p. m. Point Loma
count and the 3 to 5 p. m. Scripps
count are added together, the day
consists of 12 hours of daylight and
12 hours of darkness. A count made
on this basis would be 5 to 6 percent
greater than if the sunrise-to-sunset
division of the day is used because of
the lesser movement assumed for night.
Compared with other unavoidable in-
accuracies in the whale count, this
difference is unimportant. For the
sake of simplicity, the 50 -percent
reduction in nnigratory rate for two
hours each day is ignored.

RESULTS
Census of 1952-53

In general, the weather was good in
1952-53 and counts were high. Ehiring
this first year, the census method
was experimental, although the writer
had profited from the experience of
Dr. Hubbs. Whales were counted in-
termittently at La Jolla from Decem-
ber 3-15 and, except for five days,
an intensive watch was maintained
from December 15 through February
15. At Point Lonna, the public whale-
watch was intensive only on weekends,
December 26 through February 15, and
then continued intermittently from Feb-
ruary 16 through March 13.

On this schedule, both crews counted
whales (mostly the same individuals)
from December 26 through February
15. The higher daily count, regardless
of locality, was recorded as the value
for that day.

The La Jolla -Scripps post could not
be manned for 10 continuous hours
every day, even with the help of volun-
teers.

The Point Loma post of the Cabrillo
National Monument was never nnanned
during the public whale -watch from
7 a. m. to 9 a. m., and often not until
10 a. m. On week days, it sometimes
was not manned at all because of other
time demands upon the small, regular
staff. Consequently, a 20-percent ad-
justment was made in the daily count
for the 2 hours out of 1 0 when whales
were not counted. Even when the La
Jolla -Scripps count was nearly perfect
in coverage and visibility, and ex-
ceeded the count at Point Loma, the
20-percent extrapolation was neces-
sary because the count from 7 a. nn. to
9 a. m. at Point Loma represented
whales which had passed La Jolla
during the night or early morning and
could not have been seen there.

Extrapolation for offshore migra-
tion.--As an arbitrary correction for
whales traveling offshore, the writer
added 5 percent of the total number
estimated to have passed San Diego
within sight of land.

Census of 1953-54

At Point Loma, the National Park
Service kept watch for southbound
whales when an observer was avail-
able and when the part-time watcher

of the Fish and Wildlife Service was
off duty. Shortage of manpower and
bad weather gave unsatisfactory re-
sults. The census could not be ana-
lyzed with confidence.

Census of 1954-55

The 1954-55 census was a success.
Good weather prevailed and one of the
two whale counters employed showed
special adeptness in his work. For
the first tinne, the whale -watching post
at Point Loma was manned throughout
the season by two Fish and Wildlife
Service employees. They were con-
tinually on duty from 7 a. m. to 5
p. m., or during the entire 10 hours
of daylight.

The post at Scripps Institution of
Oceanography was also manned for
the first time continually from 3 p. m.
to 5 p. m.

Census of 1955-56

Because the census of 1955-56 was
incomplete, its results cannot be com-
pared with those of other seasons.

In addition to the posts at Point
Loma and La Jolla, an additional
whale -watching post was established
at Del Mar, five miles north of La
Jolla, for the education of Boy Scouts
under the supervision of Donald Lear,
then a graduate student at Scripps
Institution of Oceanography, La Jolla,
The hours of watching were from 4
p. m. to 5 p. m., or slightly later as
daylight and visibility conditions per-
mitted. The Del Mar data are not
utilized in the present publication.

The count for this season was low,
partly because of poor visibility and
partly because the main herd arrived
late and straggling. Severe storms
on the North Pacific in early Decem-
ber 1955 (see Danielsen and others,
1957) may have disrupted the migra-
tion and caused the whales not only
to arrive late in southern waters but
to arrive in clumps. Great gaps ap-
peared in the line of migration; sev-
eral concentrations of unusual size
were seen near San Diego.

Census of 1956-57

The season of 1956-57 was the most
successful of the five. The weather
remained fairly good. The count, as
anticipated on the basis of previous
observations by Hubbs and the writer,
proved to be the highest thus far
obtained.

Counting of southward migrants at
Point Loma by the Fish and Wildlife
Service covered 10 hours each day
during the main migration. The Na-
tional Park Service helped before and
after the regular season and on week-
ends. The supplementary watch at
Scripps Institution of Oceanography
was active from 3 p. m. to 5 p. m. or
a little later.

Table 3, giving the count of gray
whales during daylight hours, from
November 2, 1956, to March 25, 1957,
at Point Loma and La Jolla, is in-
cluded in order to show the rise and
fall of the migration.

SUMMARY OF SHORE CENSUSES

Three of five annual counts of south-
bound whales were conducted under
favorable weather conditions and were
nearly complete. These, fortxmately,
were on alternate seasons: 1952-53,
1954-55, and 1956-57, The other two
counts (1953-54 and 1955-56), made
under unfavorable weather conditions,
were incomplete. Data from the three
successful censuses indicate a steady
upward trend in the population. In
1952-53, 1954-55, and 1956-57, the
estimated populations passing San
Diego were, respectively, 2,894, 3,603,
and 4,454 (table 4). These figures
represent an increase in the estimates
of about 24 percent in each of the
2 -year periods. Such increases seem
too large for the population as a whole
when it is considered that: (1) the pop-
ulation is probably 50 percent males,
(2) females are believed to bear young
only once in two years, (3) all females
are not of breeding age, and (4) some
mortality among both young and adults
has been observed.

TJfflLE 3. — COUNTS AND EXTRAPOLATIONS OF GRAT WHALES PASSING SAN DIEGO, CALIFORNIA, DURING DAnjGHT HOURS, 1956-57

Point

La Jolla-

Total

Cumula-

Per-

Addition

Reduction

Daily

Cumula-

Date

Loma

7 a. m. -

5 p. m.

Soripps

3 p. m. -

5 p. m.

daily
count

tive
count

cent
visibility

for

whales

not seen

for slow
migration"-

total
estimate

tive
estimate

1956

2 Nov.

102

15 Deo.

16 "

104

17 "

111

18 "

128

19 "

142

20 "

151

21 "

167

22 "

101

200

23 "

123

229

2U "

146

260

25 "

184

311

26 ■'

210

346

27 "

240

379

28 "

288

432

29 "

336

485

30 "

384

549

31 "

429

609

1957

1 Jan.

485

684

2 "

536

752

3 "

2 2+11

582

833

4 "

616

901

5 "

673

977

6 "

736

1,061

7 "

745

-25

1,120

8 "

1+7

763

3 33

-15

1,156

9 "

3+15

801

-15

1,202

10 "

842

1,257

11 "

901

1,323

12 "

959

1,400

13 "

992

1,466

U "

6+1

1,039

1,528

15 "

1,088

1,593

16 "

1,134

1,654

17 "

1,193

1,720

18 "

1,229

1,760

19 "

1,275

1,811

20 "

1,306

1,873

21 "

1,347

1,928

22 "

1,400

1,987

23 "

1,438

2,038

24 "

1,451

-10

2,080

25 "

1,501

2,147

26 "

1,517

-10

2,201

27 "

1,552

-10

2,261

28 "

1,582

-10

2,311

29 "

1,598

-15

2,360

30 "

1,639

2,406

31 "

1,655

2,427

1 Feb.

1,682

2,463

2 "

1,696

-10

2,509

3 "

1,706

2,522

4 "

1,717

2,544

5 "

1,721

2,552

6 ■•

1,726

-5

2,567

7 "

1,726

-10

2,577

8 "

1,726

-10

2,587

9 "

1,726

-10

2,597

10 "

1,726

-5

2,602

18 "

113

1,839

113

226

2,828

25 Mar.

Total

1,149

-160

Number of whales deducted from estimate because of persistent bad weather; see page 21.
^ Two whales seen at La Jolla-Scripps; 11 elsewhere. Extrapolation based on 35 whales only. Similar situations are
indicated by plus-marks further down in this column.

^ Seven whales were seen from boat In fog, but missed at Point Loma. Extrapolation as follows: (11/0.25 ) minus 15 = 36.

TABLE 4.— SUMMARY OF SHORE CENSUSES OF GRAY WHALES IN SOUTHWARD MIGRATION,

1952-53 TO 1956-57

1952-53 1953-5-; 1954-55 1955-56 1956-57

Actual daily count

Daily extrapolation (bad
weather)

Estimate, all whales passing
in day

Night extrapolation

Estimate, all whales passing
San Diego

Plus 5 percent for offshore
movement

Final estimate, size of

California pop\ilation

982

800

562

1,837

919

{')

2,756

(")

138

{')

2,89A.

{')

1,646

641

2,287
1,144

3,431

172

3,603

918

{')
{')

(")

(^)

1,839
989

2,828

1,414

4,242

212
4,454

■"" No extrapolations because of incomplete data.

^ Addition of 293 for 20 percent extrapolation for 2 ho\irs not covered at Point
Loma daily.

AERIAL SURVEYS OF THE WINTERING
GROUNDS, 1952-1957

At one time, the writer believed
that air -census methods could be
standardized in time and procedure
so that land censuses might be dis-
pensed with, but his effort to accom-
plish this was unsuccessful. Large
numbers of breeding whales shift from
place to place in a short time, or
from season to season, with the result
that they cannot be found in exactly
the sanne place fronn one visit to the
next.

METHODS

Areas

The regular air surveys covered
the entire west coast of Baja Cali-
fornia and the Gulf coast from Cabo
San Lucas to La Paz --also the east
side of the Gulf, from Guaymas to
Mazatlan (fig. 4). This coverage in-
cluded all bays and lagoons in actual

or potential use by breeding gray
whales. Coverage of the east coast
of Baja California, from La Paz to
the head of the Gulf, was spotty and
inconsistent from year to year, but
all portions were covered carefully
during one year or another. Any lo-
cality consistently used by numbers
of gray whales would surely have
been found. One survey on the coast
of the mainland of Mexico went as
far south as Puerto Vallarta, 200
miles south of Mazatlan, and another
to Manzanillo, another 1 25 nniles south,
in latitude 18°N. No gray whales were
definitely seen south of Reforma.

Procedure

The time selected for air surveys
was February, after most gray whales
had reached the breeding and calving
bays and lagoons, and when only a
few had departed for the north. Shore

counts, and estimates based on them,
of total southward migration, indicate
that over 90 percent of the northeast
Pacific migratory population are in
the aerial-census area at this time.
Air censuses in the first three weeks
of February appear to have been the
most successful. The most favorable
meteorological conditions for flight
census were a strong, high-pressure
area over the western United States
which brought an easterly, or land
breeze, from the interior to the coast
of southern California and Baja Cali-
fornia. This wind, locally called a
"Santa Ana," pushed away the usual
coastal fog and smoothed the water
surface by counteracting the prevailing
northwest wind. The best time of day
for air surveys was morning when air
was clearest, wind weakest, and sur-
face visibility best. The position of
the s\ui influenced visibility, but the
plane could often be maneuvered to
the sun-side of the migration path or
lagoon.

The first air survey was carried
out from a Cessna 170. Later a Cessna
180, or Piper Supercub with floats,
and finally a Grumman Widgeon, a
five -passenger amphibian, were used.
The success of all flights can be
attributed, in part, to the efforts of
Dr. Gifford C. Ewing, owner and pilot
of the aircraft.

The course of the aircraft in flight
along the coast was one to three miles
offshore, depending on the contour of
the coast. It was closer to the head-
lands, farther out across the open bays
and bights. The aircraft flew at about
90-knot speed at an elevation of 1,000
to 1,500 feet over the coastal waters.
This altitude over the ocean gave fair
coverage of a half mile or so on each
side and allowed quick recognition of
any whale below. When time pressed,
speed was increased to 110 or 120
knots, and the altitude to 2,000 feet,
without substantial loss of accuracy.

Over lagoons, the plane dropped to
500 or 750 feet. The lower altitude
was high enough for lateral coverage
because the channels were narrow,
and yet was low enough for recognition

of calves. Despite the low elevation,
however, a certain number of calves
were undoubtedly missed, even when
their mothers were in full view at the
surface. Rough water was particularly
disadvantageous for spotting calves.
Very young calves stayed close to the
mother's side and, when nursing, were
sometimes observed to be partially
hidden by her. It is assumed that a
few must have been entirely hidden.

In the lagoons, the period of time
spent by a gray whale under the sur-
face is extremely variable. A whale
averages about four minutes below
the surface, when it cannot be seen.
It spends about a minute at or near
the surface, blowing from two to four
times. About one -fourth of the whales
beneath the plane could perhaps be
seen by the observers at any time.

RESULTS

Survey of 1952

An air survey was made in 1952,
February 16-20, by Dr. Carl L. Hubbs
and Dr. Gifford C. Ewing. As it was
similar to later censuses, it has been
included here (table 5) with the kind
permission of Hubbs and Ewing. The
entire west coast of Baja California
was covered, including the principal
lagoons and the Gulf coast from Santa
Rosalia southward, although no gray
whales were seen in the Gulf of Cali-
fornia.

Survey of 1953

Two aerial surveys were made dur-
ing the 1952-53 season. The first was
made from January 31 through Feb-
ruary 3, 1953, Although the season
was early, the weather was excellent
and the results were good. The flight
was made in a Cessna 170. The entire
west coast of Baja California was
covered, except for the section from
Laguna Scammon to Laguna San Ignacio
and a small portion from Boca Las
Animas to Boca Soledad, north of
Bahia Magdalena.

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The second survey was made from
February 25 through 27, 1953, in a
Cessna 170. The entire west coast of
Baja California from Cabo San Lucas
to San Diego, was covered and also
the Gulf side from Santa Rosalia about
midway to the Cape.

Survey of 1954

The first air survey covered the
dates February 1 through 7, 1954, and
was made in a Piper Supercub with
floats. However, the survey was in-
complete because it was cut short at
Laguna San Ignacio on the way north
from La Paz.

A second air survey was carried out
from February 15 through 18 by Hubbs
and Ewing, who covered the same
course as the earlier flight and com-
pleted the survey back to San Diego.
About 1,200 adults and immatures and
200 calves were seen in this second
survey.

Survey of 1955

The survey of 1955 was incomplete.
The Grumman Widgeon developed
motor trouble on March 4 and the
survey was stopped just beyond San
Ignacio on the west coast of Baja
California. On February 26, a survey
was made of the "Northern" area
from San Diego to Ensenada. The
survey covered the Gulf at Yivaros
and Refornna, and the Cape, Magdalena,
San Juanico, and San Ignacio areas
from February 27 through March 3.

On February 4, 1955, Dr. Gifford C.
Ewing, Dr. Fred Phleger, and Mr.
Robert Lankford flew over Laguna
Scammon and counted 121 adult .or im-
mature gray whales and 69 calves.

Survey of 1956

The survey of 1956 was conducted
from February 14 through 17. The
Grumman Widgeon, a twin-engine am-
phibian, was used again. Vision from
the Widgeon was not as good as from

the Cessna 170, the Cessna 180, or
the Piper Supercub with floats. Opera-
tion of the plane required nearly all
of the pilot's time and he was, thus,
unable to participate in the census.
A second watcher on the port side
was added, although he was forced to
look through a small window which
limited his field of view.

During the 1955 flight, the plane had
been maneuvered so that most or all
of the whales could be viewed from
the starboard side, where the writer
sat. During the 1956 flight, attempts
to place both port and starboard ob-
servers in an advantageous position
resulted in fewer whales being seen
by the two observers than by one in
1955. To eliminate the blind spot under
the plane, a zigzag technique was tried
which involved weaving back and forth
in S-shaped curves over the channels
of the lagoons. This made the covmt
slow and interrupted as every other
turn placed the observer on the high
side of the plane where he was unable
to see the water. The zigzag technique
was thoroughly tested in Laguna Scam-
mon and perhaps 30 percent of the
whales, which otherwise would have
been visible, were missed. Zigzagging
was therefore abandoned.

Three areas were not covered during
the 1956 survey (1) the entire Vizcaino
area; (2) the 130 miles of coast from
Boca Las Animas to Boca Almejas
outside the Magdalena area; and
(3) about 50 miles of the coast on the
Cape, west of the La Paz area.

Results of this air survey, based on
a table prepared by the Fish and
Wildlife Service, were published by
Berdegue (1956).

Survey of 1957

The 1957 air survey of the winter
grounds of Baja California and the
Gulf of California was made by the
Fish and Wildlife Service in coopera-
tion with Scripps Institution of Ocea-
nography and the Richfield Oil Com-
pany from February 27 through March
3, 1957. The Grumman Widgeon was

again used. The flight was made in
good weather and provided excellent
coverage, but the number of whales
was disappointingly small.

SUMMARY OF AERIAL SURVEYS

Because the air -survey method in-
troduced many variable factors, and
information needed to apply corrections
was not available, it is unwise to
estimate the size of the total popula-
tion on air -survey data. However, an
air survey is the only way to deter-
mine the extent of breeding grounds,
the relative use of areas as calving
grounds, and changes from year to
year.

The breeding areas may, as a result
of the aerial surveys, be ranked as
follows :

Vizcaino -Scammon area. --This is
the most important of the winter calv-
ing areas. During the five years of
the surveys, it might have held numbers
of whales varying from 1,500 to 2,000,
or about half the total population.

Magdalena area. --This is the second
most important calving ground. Per-
haps 1,000 to 1,500 whales, or about

one-third the total population, visited
the area during each year of the 5-
year period of the surveys.

San Ignacio area. --This is the third
most important spot for calving and
mating, with perhaps 500 whales, or
between one-teighth and one -sixth the
total winter population.

Reforma area. --The highest count
made at one timie here was 18 adults
and 12 calves.

Yavaros area. --Evidently only small
numbers of whales used the Yavaros
area. The highest count was 10 adults
and 7 calves.

The area available for calving and
mating may be the most critical factor
in determining eventual size of the
population. Reduction of this area by
natural (geological) events or by man
may have a pronounced effect in lower-
ing the population ceiling. Man -modi-
fied or man -disturbed lagoons and bays
which should be carefully watched are
Bahia San Quintin, Laguna Guerrero
Negro, Bahia Magdalena, Bahia Re-
forma, and the Yavaros area. Continued
studies of these areas will help to
evaluate the relationship between gray
whales and man (see table 5).

LITERATURE CITED

ANDREWS, R. C.

1914. The California gray whale
(Rhachianectes glaucus). Memoirs
of the American Museum of
Natural History, l(5):227-287.

ANTHONY, A. W.

1921. The California gray whale
on the coast of southern Cali-
fornia. Journal of Mammalogy,
2(3):174.

BERDEGUE, J.

1956. Ultimo censo de la ballena
gris, Rhachianectea glaucus (Cope)
en aguas de Baja California.
Ciencia, l6(4-6):99-109.

CEDERLUND, B. A.

1939. A subfossil gray whale dis-
covered in Sweden in 1859.
Zoologiska Bidrag fr&n Uppsala,
18:269-286.

COPE, E. D.

1868. [Remarks on Cetacea at
meeting of 23 June.] Proceed-
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Sciences of Philadelphia,
20:159-160.

1869. Systemiatic synopsis of the
species of the cetaceans of the
west coast of North America.
Proceedings, Academy of Natu-
ral Sciences of Philadelphia,
21:14-32.

DANIELSEN, E. F., W. V. BURT,
AND M. RATTRAY
1957. Intensity and frequency of se-
vere storms in the Gulf of
Alaska. Transactions, Ameri-
can Geophysical Union, 38(1):44-
49.

DEINSE, A. B. VAN, AND G. C. A.

JUNGE.

1937. Recent and older finds of the

California gray whale in the

Atlantic. Temminckia, 2:161-

188.

DUDLEY, P.

1725. An essay upon the natural
history of whales. Philosophi-
cal Transactions of the Royal
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ELLERMAN, J. R., AND T. C.S.MOR-
RISON-SCOTT.
1951. Checklist of Palearctic and
Indian mammals. British Mu-
seum (Natural History), London,
810 pp.

ERXLEBEN, J. C. P.

1777. Systema regni animalis.
Lipsiae, 636 pp.

FRASER, F. C.

1937. Early Japanese whaling.
Proceedings of the Linnean So-
ciety, 150(l):19-20.

GILMORE, R. M.

1955. The return of the gray whale.
Scientific American, 192(1):62-
67.

GRAY, J. E.

1864. Notes on the whalebone -
whales; with a synopsis of the
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1865. Notice of a new whalebone
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shire. Proceedings of the Zoo-
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1865:40.

HOWELL, A. B., AND L. M. HUEY.
1930. Food of the gray and other
whales. Journal of Mammal-
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ICHIHARA, T.

1958. Gray whale observed in the
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LILLJEBORG, W.

1861. Hvalben, funna i jorden paa
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n a V i s k a Naturforskaremotet,
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MILLER, G. S., AND R. KELLOGG.
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MIZUE, K.

1951. Grey whales in the East Sea
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PALLAS, P. S.

1811. Zoographia Rosso-Asiatica.
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RISTING, S.

1928. Whales and whale foetuses.
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SCAMMON, C. M.

1874. The marine mammals of the
northwestern coast of North
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SCHEVILL, W. E.

1954. On the nomenclature of the
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7:1-3.

SLEPTSOV, M. M.

1955. Cetacea. IN Geographic dis-
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economically important animals
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Trudy, Akademiia Nauk SSSR,
Institut Okeanologii, vol. 14. (In
Russian).

SLIJPER, E. J.

1958. Walvissen. D. B. Centen's,
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TOMILIN, A. G.

1957. Mantunals of the U.S.S.R. and
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1934. Some data on whales of the far
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B.C.F. »02-4-60

GPO 8>II4S

""' -Smm

5 WHSE 01470

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