537

Pelagic Fur Seal Investigations, 1965

By Clifford H. Fiscus and Hiroshi Kajimura

Marine Biological Labora;ory

LIBRARY

JULl ''ilQG

WOODS HOLE, MASS.

SPECIAL SCIENTIFIC REPORT-FISHERIES Na 537

UNITED STATES DEPART/V\ENT OF THE INTERIOR

FISH AND WILDLIFE SERVICE
BUR E AtroTcOMMERciATF ISHERIE^

UNITED STATES DEPARTMENT OF THE INTERIOR

Stewart L. Udall, Secretary

Charles F. Luce, Under Secretary

Stanley A. Cain, Assistant Secretary for Fish and Wildlife and Parks

FISH AND WILDLIFE SERVICE, Clarence F. Pautzke, Commissioner

Bureau of Commercial Fisheries, Harold E. Crowther, Acting Director

Pelagic Fur Seal Investigations, 1965

by

CLIFFORD H. FISCUS and HIROSHI KAJIMURA

United States Fish and Wildlife Service
Special Scientific Report- -Fisheries No. 537

Washington, D.C.
February 1967

CONTENTS

Page

Introduction 1

Equipment, methods, and personnel 2

Research in 1965 2

Distribution off Washington 2

Distribution off California 2

Relative abundance of seals and size of groups 4

Distribution by age and sex 4

Tag recoveries 4

Size 4

Reproduction 4

Reproductive condition 8

Pregnancy rate 8

Uterine horn of conception and fetal sex ratio 8

Attached organisms (commensals) 8

Food 10

Relation of fur seals to commercial fisheries 13

Summary 13

Literature cited 14

Appendix A 16

Tables 16

Figures 25

Appendix B 33

Observation of Japanese pelagic fur seal research, 1965 33

Appendix C 40

Behavior notes 40

Appendix D 41

Injured, sick, and diseased fur seals collected pelagically by the U.S.A. in the eastern

Pacific in 1965 41

Appendix E 42

Fetal nnortality during the last 6 months of gestation 42

TABLES

1. Age and sex, by month and area, of fur seals collected pelagically by the U.S.A. in 1965. 6

2. Age and sex of fur seals collected pelagically off California, by month 7

3. Tag recoveries from fur seals collected pelagically by the U.S.A. in 1965 8

4. Number of female seals collected pelagically by the U.S.A. in the eastern Pacific and

(in parentheses) percentage pregnant, 1958-65 9

5. Number and percentage of seals collected off California in 1965 with algae or barnacles

growing on guard hairs 10

6. Stomach contents of fur seals collected off California, 1965 11

7. Stomach contents of fur seals collected off Washington, 1965 11

FIGURES

Number of seals observed (upper figure in each square) and collected (lower) fronn

lat. 46° N. to lat. 48° 40' N, The sides of each square measure 10 nautical miles. . . 3
Number of seals observed (upper figure in each square) and collected (lower) from

lat. 35° 20' N. to lat. 37° N. The sides of each square measure 10 nautical miles. . . 5
Number of seals observed (upper figure in each square) and collected (lower) from

lat. 37° N. to lat. 38° 30' N. The sides of each square measure 10 nautical miles. . . 5
Percentage of stomach content volume and percentage occurrence of principal food

species in fur seal stomachs, by area, in 1965 12

Page
APPENDIX TABLES

A-1, Distribution and migration studies: seals observed along transects, 1965 16

A-2. Number and relative abundance of seals seen, by 10-day periods, off California and

Washington, 2 April to 23 June 1965 16

A-3. Number and relative abundance of seals collected, by 10-day periods, off California

and Washington, 2 April to 23 June 1965 17

A-4. Number of seals per group among 1,627 seals sighted off California and Washington,

2 April to 23 June 1965 17

A-5. Monthly mean lengths of pregnant fur seals collected pelagically by the U.S.A. in

the eastern Pacific in 1965 18

A-6. Monthly mean weights of pregnant fur seals collected pelagically by the U.S.A. in

the eastern Pacific in 1965 18

A-7. Monthly mean lengths of nonpregnant female fur seals collected pelagically by the

U.S.A. in the eastern Pacific in 1965 19

A-8. Monthly mean weights of nonpregnant fennale fur seals collected pelagically by the

U.S.A. in the eastern Pacific in 1965 20

A-9. Monthly mean lengths of male fur seals collected pelagically by the U.S.A. in the

eastern Pacific in 1965 21

A- 10. Monthly mean weights of male fur seals collected pelagically by the U.S.A. in the

eastern Pacific in 1965 21

A- 11. Monthly mean lengths and weights of fur seal fetuses collected pelagically by the

U.S.A. in the eastern Pacific in 1965 21

A- 12. Reproductive condition, by month, of female fur seals collected pelagically by the

U.S.A. off California in 1965 22

A- 13. Reproductive condition of female fur seals collected pelagically by the U.S.A. off

Washington in April 1965 23

A- 14. Pregnancy rates of female seals collected pelagically by the U.S.A., by area and

month, in 1965 24

B-1. Harpoon vessels chartered for fur seal research by Japan in 1965 33

B-2. Number of seals seen and collected by the Nikko Maru, 10 April to 10 May 1965. . . 36
C-1. Observations by the U.S.A. of unusual fur seal behavior in the eastern Pacific in

1965 40

D-1. Injured, sick, and diseased fur seals collected pelagically by the U.S.A. in the

eastern Pacific in 1965 41

E-1. Eight-year summary of pregnancy rates of seals collected pelagically by the U.S.A.

from California to Alaska 42

APPENDIX FIGURES

A1-A8. Locations where fur seal stomachs collected in 1965 contained: 1. Trachurus
symmetricus, Myctophidae, Gonatopsis borealis , Lampetra tridentata; 2. Clu-
peidae, Loligo opalescens: 3. Onychoteuthis banksii, Clupea harengus pallasi,
Thaleichthys pacificus; 4. Engraulis mordax, Gonatus fabricii; 5. Abraliopsis sp.,
Gonatus magister, Moroteuthis robusta, Oncorhynchus spp.; 6. Cololabis saira,
Tremoctopus sp., Pleuronectidae, Gasterosteus aculeatus; 7. Merluccius pro-

ductus ; 8 . Sebastodes spp., Anoplopoma fimbria 25-32

B-1. Biologist, in front of field station laboratory at Akahama 33

B-2. Fishing villages visited by the Nikko Maru, 10 April to 10 May 1965 34

B-3. A harpoon vessel, the No. 5 Nikko Maru, of the type chartered for fur seal re-
search 35

B-4, Crew members of the chartered fur seal research vessel. No. 5 Nikko Maru .... 35

B-5. Hunters shooting fur seal from bow platform 35

B-6. The tiller, located on the stern, improves the maneuverability of the vessel 36

B-7. Deckhands ready to throw retrieving pole to recover dead seal 36

B-8. Calibrated board for measuring seals on vessel 37

B-9. Weighing fur seal with a graduated beam scale 37

B-10. Cutting off snout to preserve upper canine teeth for age determination 37

B-11. Sealskins being unloaded from vessel 38

B-12. Salted skins being folded and placed in burlap bags 38

B-13. Bundles of sealskins being prepared for shipment to processing plant 38

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Pelagic Fur Seal Investigations, 1965

By

CLIFFORD H. FISCUS, Wildlife Biologist, and
HIROSHI KAJIMURA, Fishery Biologist

Bureau of Commercial Fisheries

Marine Mammal Biological Laboratory

Seattle, Wash. 981 15

ABSTRACT

Pelagic fur seal research as required by the Interim Convention on Conserva-
tion of North Pacific Fur Seals was conducted off Washington (2-24 April) and off
California (11 April to 23 June). One hundred forty- seven fur seals (Callorhinus
ursinus) were taken off Washington and 269 off California, Off Washington, seals
were most numerous near Grays Harbor in mid-April. Off California, seals were
concentrated off Monterey fronn late April to early June and near Cordell Bank west
of Pt. Reyes in April and early May. Observation or transect lines extending from
10 to 80 miles offshore were established between Bodega Head and Pt, Sur, Calif.,
at 20-mile intervals, to study distribution and migration. Seals were most abundant
from 30 to 40 miles offshore. Of the 387 female seals taken, 44 percent were preg-
nant; the youngest pregnant females were 5 years old, A squid, Moroteuthis robusta,
is reported for the first time as fur seal food. By volume, the principal species of
fish eaten by seals off California was Merluccius productus and off Washington was
Engraulis mordax.

INTRODUCTION

The United States has engaged in pelagic
research on fur seals intermittently since
1883. In that year James G. Swan (1883), U.S.
Fish Commission, worked on seals brought
into Neah Bay, Wash., by Indian sealers.

Charles H. Townsend (1898) and A. B.
Alexander (1892)' of the U.S. FishConnmission
began pelagic studies in 1892 fronn the U.S.
Revenue Marine Cutter Corwin in the Bering
Sea and Gulf of Alaska. Townsend, Alexander,
and Frederic A. Lucas continued ocean inves-
tigations in 1896 under a commission headed
by David Starr Jordan (Jordan, 1 899). Between
1896 and 1952 no large-scale investigations
were carried out. Observations and collections
made by many observers during this time are
summarized by Taylor, Fujinaga, and Wilke
(1955).

As part of cooperative investigations by
Canada, Japan, and the United States in 1952,
Victor B, Scheffer collected seals offshore

'In Records of the United States Fish Commission,
prepared by General Services Administration, The National
Archives, Washington, D,C., 1953 (Record Group 22),
(Manuscript report by A. B, Alexander concerning fur
seals, 1892, 23 p.)

from California to Alaska (Taylor, Fujinaga,
and Wilke, 1955). Wilke and Kenyon (1957)
studied food habits of fur seals in the Bering
Sea in 1955.

Pelagic research under the Interim Conven-
tion on Conservation of North Pacific Fur
Seals began in 1958. Mennbers of the Conven-
tion are Canada, Japan, the U.S.S.R., and the
United States.

One objective of the Convention is to deter-
mine "what the relationship is between fur
seals and other living marine resources and
whether fur seals have detrimental effects on
other living marine resources substantially
exploited by any of the Parties, and, if so, to
what extent." The first part of this objective
will probably never be entirely satisfied, and
though we have acquired detailed knowledge
about the food of fur seals, the effects result-
ing from their feeding are obscure and likely
to remain so indefinitely.

Other research required by the Convention
is partly completed. The migration routes of
fur seals and their wintering areas are gen-
erally known, but relatively little information
is available on far-offshore distribution and
the movements of seal pups during their first
months at sea. The age and sex of seals mov-
ing and feeding off the coast during different

months are generally known, but little progress
has been nriade on estimating the numbers of
seals on migration routes and in wintering
areas in the eastern Pacific. Sampling indi-
cates, however, that few seals under age 8
originating from Robben Island or the Com-
mander Islands migrate along the coast of
North America.

The most dependable data on pregnancy and
mortality rates are obtained from seals col-
lected at sea. These data are essential for
population and recruitment estimates for the
Pribilof seal herd.

Investigations off California from April to
June 1965 expanded studies carried on in the
spring of 1964. A collection of seals on the
salmon trolling grounds off Washington pro-
vided information about these animals in an
area where a salmon population was present
during the time of the study.

EQUIPMENT, METHODS, AND PERSONNEL

Vessels, boats, equipnnent, and methods used
in hunting and in collecting data were described
by Fiscus, Baines, and Wilke (1964). Equip-
ment and methods are now standardized, al-
though specialized equipment and techniques
are used dependent on collecting requirements.
The frontispiece shows a dory equipped for
sealing. Equipment carried in dories has been
selected on the basis of experience at sea
since 1958.

Seals are taken frona the vessel, or from a
dory, with 12-gage shotguns, loaded with buck-
shot. Seals are weighed, measured, and skinned,
and the stomachs, reproductive tracts, and
right upper canine teeth are saved for exami-
nation in the laboratory (ages are determined
from longitudinal sections of the canine teeth).

A study of the accuracy of determining age
from upper canine teeth of fur seals is in
progress at the Marine Mammal Biological
Laboratory. Preliminary results in reading
the ages of sectioned teeth of seals of known
age indicate the following percent error: males
age 2 through 5, error by three readers (33
teeth) ranged from 9 to 24 percent with the
greatest error of tl year; females age 1
through 7, error for three readers (93 teeth)
ranged from 9 to 25 percent with 99 percent
differing by no more than +1 year and a
greatest error of +2 years; females 8 through
13, error for two readers (39 teeth) ranged
from 41 to 59 percent with 91 percent within
i\ year and a greatest error of -4to +2 years.
The sample of known- age males age 6 and
females age 14 and older was too small to
use in this study.

The method of handling skins described by
Fiscus and Kajimura (1965) was modified in
1965 to include blubbering (the act of removing
fat, muscle, and connective tissue from the
skin) prior to salting. This was done to deter-
mine if differences in quality of curing existed

between skins blubbered soon after collecting
and those blubbered several weeks to several
months after they were taken. After a skin was
stripped from the seal carcass and washed, it
was soaked in clean sea water overnight, then
blubbered on a portable fleshing beam, drained,
and cured in salt for 2 weeks before barreling.

Observations of marine mammals and col-
lections of fur seals in 1965 were made off
Washington from the chartered purse seiners
M/V St. Michael' 2-4 April and M/V Har-
mony' 6-24 April; the St. Michael was also
used off central California 11 April to 23 June.

Records for three female seals are not
complete. These three animals are included in
the sections on distribution of seals by date
and locality, and relative abundance and size
of groups, only.

Biologists aboard the St. Michael were Clif-
ford H, Fiscus and Hiroshi Kajimura. Biolo-
gists on the Harmony were Raymond E, Anas,
Alton Y. Roppel, and Ford Wilke. Assistants
on the vessels and in the Seattle laboratory
were Richard K. Stroud and James A. Wood.
Allan H. Vogel assisted in the Seattle labora-
tory. Hiroshi Kajimura observed pelagic re-
search in Japan from 10 April to 10 May 1965
(app. B).

RESEARCH IN 1965

In 1965, fur seal research was carried out
at sea off the coast of Washington between lat,
46° N. and 49° N., in April, and off the coast
of California between lat. 36° N. and 39° N.,
from April to May.

Distribution off Washington

Seals were widely scattered and scarce off
Cape Flattery and the northern Washington
coast in early April; however, in mid-April
concentrations of seals were located 10 to 20
miles off Grays Harbor (fig. 1). For example,
96 seals were seen 1 5 April and 145 on 22 April
in water from 30 to 100 fathoms (55 to 182 m.)
deep.

Surface water temperatures off Washington
ranged from 8° to 12° C. in the survey areas.
Off Cape Flattery, temperatures were mostly
10° to 11° C.

Distribution off California

With two exceptions, investigations were
carried out between Bodega Head (lat. 38° 18'
N.) and Pt, Sur (lat. 36° 18' N.) from shore to
about 100 miles out. Two cruises were made
south from Pt. Sur to Morro Bay (lat. 35° 23'
N.) to survey what in the past has been a

2 M/V St. Michael: registered length 72.5 feet, 107
gross tons, 380 horsepower, cruising speed 10 knots.

'M/V Harmony: registered length 70.5 feet, 90 gross
tons, 220 horsepower, cruising speed 9 knots.

124°

Figure 1. — Number of seals observed (upper figure In each square) and collected (lower) from lat. 46° N.
to lat. 48° 40' N. The sides of each square measure 10 nautical miles.

major wintering area. Although visibility was
excellent during both surveys, only 21 seals
were seen on the first cruise (28-29 May)
and 1 on the second (21-22 June),

A concentration of seals was located north
of Pt. Sur in and near the Monterey seavalley
from late April to early June. Seals were on
the Farallon grounds southwest and west of the
Farallon Islands throughout the surveyperiod.
Concentrations of seals were also observed
on or near Cordell Bank west of Pt. Reyes in
April and in early May.

Seals off California seldom come close to
land; however, during a severe storm on
14 April we saw an adult female about a half
mile from shore at the western approach to
Drakes Bay. Seals were abundant offshore at
this time.

Seven observation or transect lines were
established between Bodega Head and Pt. Sur
at 20-nnile intervals as a basis for a system-
atic study of the distribution and migration of
fur seals off California. These lines, which
extended from 10 to 80 miles out from shore
(figs. 2 and 3), were cruised once each month,
and the seals seen were recorded (table A-1).
Because of the annual northward migration,
the number of seals seen per month decreased
from 264 in April to 72 in June. Seals were
most abundant from 30 to 70 miles offshore
(figs. 2 and 3). The greatest concentration was
from 30 to 40 miles offshore; abundance de-
creased rapidly toward shore and gradually
between 40 and 80 miles out. The largest
number of seals seen in 1 day in each month
were: 16 April - 101, 26 May - 66, and 14
June - 46. Thirty seals were seen on the last
day (23 June) in the area.

Surface water temperatures off California
ranged from 10° to 14° C. in the areas sur-
veyed. Temperatures were mostly 11° to 12°
C. in April and May and 12° to 13° C. in June.

Relative Abundance of Seals and Size
of Groups

The number and relative abundance of seals
seen and collected, by 10-day periods, are
shown in tables A- 2 and A- 3. The decreasing
number of seals seen per boat- hunting day off
California in April, May, and June, is a result
of the annual northward migration to the
Pribilof Islands breeding grounds. This de-
crease was not apparent off Washington, where
the survey ended at about the peak of migra-
tion.

A group of seals is defined as one or more
seals that are feeding, traveling, or resting in
close association with each other. A single
seal is recorded as a group of 1. Seals sepa-
rated from each other by more than 100 yards
are recorded as separate groups. The per-
centage of seals in each group for Washington
and California combined (table A-4) did not
change greatly from that observed in 1964

(Fiscus and Kajinnura, 1965); however, the
proportion of single animals off California
increased from 29.8 percent in 1964 to 50.6
percent in 1965.

As an example of seal grouping during
migration, 67 animals observed moving north
off Pt. Reyes, Calif., 29 April, were divided
among groups of the following sizes (number
of groups in parentheses): 1 seal - (12 groups),
2 - (3). 3 - (4), 4 - (3), 5 - (2), 7 - (1), 8 - (I).
More than 70 percent of the seals were in
groups of 3 to 8; groups as large as these are
more conamon when seals are migrating than
when they are on their wintering grounds off
California.

Of 1,627 seals sighted in 1965, 419 were
collected, 50 were wounded and lost, and 46
were killed and lost.

Distribution by Age and Sex

The age and sex of seals collected in 1965,
by months and areas, are shown in table 1.
Distribution by age and sex off California is
similar to that of 1964 (Fiscus and Kajimura,
1965).

Monthly changes in the age and sex compo-
sition of fur seals collected off California
(data for 5 years combined) are shown in
table 2. The number and proportion of young
males increase in April and May and decrease
in June, when seals of all ages beconne less
numerous. Males consistently form only a
small part of the seal population off California;
the few males collected were young. The grad-
ual increase in the proportion of young (ages
1-4) females off California from 9.8 percent
in January to 39.8 percent in June is a result
of the northward migration of naany of the
older females toward the breeding grounds.

Tag Recoveries

Twenty tagged seals were taken in 1965. Of
the seals killed and recovered in 1965, 12
percent of the seals age 4 and younger and
1 percent of those age 5 and older had been
tagged (table 3). No seals tagged on Robben
Island or the Commander Islands were taken.

Size

Lengths and weights are given for pregnant
and nonpregnant females collected in 1965 in
tables A-5 to A-8 and for males in tables A-9
and A- 10. Mean lengths and weights of male
and female fetuses collected in 1965 are shown
by 1 0-day periods in table A- 1 1 .

Reproduction

Diagnosis of the reproductive condition of
female fur seals is important in the study of
possible segregation at sea by age, sex, or
reproductive condition, and for the evaluation
of pregnancy rate data.

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Figure 2. — Number of seals observed (upper figure in each square) and collected (lower) from
lat. 35° 20' N. to lat. 37° N. The sides of each square measure 10 nautical miles.

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Figure 3. — Number of seals observed (upper figure In each square) and collected (lower) from
lat. 37° N. to lat. 38° 30' N. The sides of each square measure 10 nautical miles.

-Age and sex, by month and area, of fur seals collected pelagically
by the U S- A in 1965

California

Washington

Total

Age

Male Female

Male Female

Male Female

Years

Number

Percent Number

1
3
100.0 3
6
2
5
2
1
4
2
4
3
1
2

2

2

Percent

2. 3

7.0

7.0
14. 0

4.6
11.7

4.6

2. 3

9.4

4.6

9.4

7.0

2. 3

4.6

4.6
4.6

Number

6
3
8
2

Percent Number

April

31.6 6

15. 8 2

42. 1 20

10.5 27

8

18

12

16

3

2

4

1

1
2
2
1
2
1

Percent

4.6

1.6
15.6
21. 1

6. 2
14. 0

9. 4
12. 5

2. 3
1.6

3. 1
0.8

0.8
1.6
1.6
0.8
1.6
0.8

Number

6

3

10

2

Percent Number

28.6 7

14. 3 5

47.6 23

9. 5 33

10

23

14

17

7

4

8

4

1

3

2

4

3

2

1

Percent

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

20

2

4. 1
2.9
13. 4
19. 3
5.9
13.4
8.2
9. 9
4. 1
2. 3
4. 7
2. 3
0.6
1.8
1.2
2. 3
1.8
1. 2
0.6

Total

2

43

19

128

21

171

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

23

2
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40. 0 3

2

11

60.0 2 1
6
7
5
9
5
3
6
9
3
6
8
5
6
3
2
1
1
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2.4
1.6
8.9
17. 1
4.9
5.7
4. 1
7. 3
4. 1
2. 4
4.9
7. 3
2.4
4.9
6.6
4. 1
4.9
2. 4
1.6
0.8
0.8
0.8

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40.0 3

2

11

60.0 21
6
7
5
9
5
3
6
9
3
6
8
5
6
3
2
1
1
1

2.4
1.6
8. 9
17. 1
4. 9
5.7
4. 1
7. 3
4. 1
2.4
4. 9
7. 3
2.4
4.9
6.6
4. 1
4.9
2. 4
1.6
0.8
0.8
0.8

Total

5

123

-

-

5

123

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

3

100.0

1
17
19
7
7
5
7
5
3
4
2
4
1
4
3
1
3

1. 1
18. 3
20.4
7. 5
7. 5
5.4
7. 5
5.4

3. 2

4. 3
2.2
4. 3
1. 1
4. 3
3.2
1. 1
3.2

-

June

-

3

100.0

1
17
19
7
7
5
7
5
3
4
2
4
1
4
3
1
3

1. 1
18. 3
20.4
7. 5
7. 5
5. 4
7. 5
5.4

3. 2

4. 3
2.2
4. 3
1. 1
4. 3
3.2
1. 1
3.2

Total

3

93

-

-

3

93

Table 1. --Age and sex, by month and area, of fur seals collected pelagically
by the U.S.A. in 1965--Continued

California

Washington

Total

A^e

Mai

e

Female

Male

Female

Mai

■ Female

Years

Number

Percent

Number

Percent

Number

Percent Number

Percent

Number

Percent Number

Percent

5

50. 0

4

1. 5

6

Combined totals

4.6

11

37.9 10

1

31.6 6

2.6

I

-

-

6

2. 3

3

15. 8 2

1.6

3

10. 3 8

2. 1

3

2

20.0

31

12. 0

8

42. 1 20

15.6

10

34.5 51

13.2

4

3

30.0

46

17. 7

2

10. 5 27

21. 1

5

17.2 73

18. 8

5

-

_

15

5.8

-

8

6.2

-

23

5.9

6

_

-

19

7. 3

-

18

14.0

37

9.6

7

_

_

12

4.6

-

12

9.4

-

24

6.2

8

_

_

17

6.6

-

16

12. 5

-

33

8. 5

9

_

-

14

5.4

-

3

2. 3

-

17

4. 4

10

_

-

8

3. 1

-

2

1.6

-

10

2.6

11

_

_

14

5.4

-

4

3. 1

-

18

4.6

12

_

_

14

5.4

-

1

0.8

-

15

3.8

13

-

-

8

3. 1

-

-

-

-

8

2. 1

14

-

-

9

3. 5

-

1

0.8

-

10

2.6

15

-

-

12

4.6

-

2

1.6

-

14

3.6

16

-

.

10

3. 9

-

2

1.6

-

12

3. 1

17

-

-

9

3. 5

-

1

0.8

-

10

2.6

18

_

_

6

2. 3

-

2

1.6

-

8

2. 1

19

-

-

2

0.8

-

-

-

-

2

0. 5

20

-

-

1

0.4

-

1

0. 8

-

2

0. 5

21

-

-

1

0.4

-

-

-

-

1

0. 3

23

-

-

1

0. 4

-

-

-

1

0. 3

Total

10

259

19

128

29

1

387

Table 2. --Age and sex of fur seals collected pelagically off California, by month"
[Combined data for 1958, 1959, 1961, 1964. and 1965]

1/

1/ Data for 1958, 1959, and 1961 from North Pacific Fur Seal Commission (1964);
data for 1964 from Fiscus and Kajimura (1965).

2/ All males are age 4 or less, except one 5-year-old collected in 1964.

Seals
collected

Males-'

Females

Month

Females

Ages

1-4

Ages

5-20 +

Niimber

Number

Percent

Number

Percent

Number

Percent

Number

Percent

Jan.

546

4

0. 7

542

99. 3

53

9.8

489

90.2

Feb.

1. 194

2

0. 2

1, 192

99.8

103

8.6

1, 089

91.4

Mar.

611

5

0.8

606

99.2

90

14. 9

516

85. 1

Apr.

474

26

5.5

448

94.5

98

21.9

350

78. 1

May

332

18

5. 4

314

94.6

97

30. 9

217

69. 1

June

96

3

3. 1

93

96.9

37

39.8

56

60.2

Table 3. --Tag recoveries from fur seals collected pelagically by the U.S.A. in 1965
[Figures in parentheses indicate animals that had lost tags; they are included in the totals. ]

Year
of

tagging

Tag
series

Locality o

f tag recovery.

and sex

Seals CO

Uected in

Age

Seals
tagged

California

Wash

ington

each age groupL'

cT

■?

cf

?

d"

?

Years

No.

No.

No.

No.

No.

No.

No.

1

1964

Q

24, 991

1

-

-

-

11

10

2

1963

P

24, 971

-

-

-

-

3

8

3

1962

O

49, 908

1(1)

2

1(1)

2(1)

10

51

4

1961

N

49, 921

-

4(1)

1

5(2)

5

73

5

1960

M

59, 981

-

1

-

-

-

23

6

1959

L

49, 881

-

-

-

1(1)

-

37

11

1954

G

10, 000

-

1

-

-

-

18

ly Table does not include seals born in years when no tagging was done, or
year classes from which no tagged seals were taken.

Reproductive condition.- -Of the females col-
lected off California and Washington in 1965,
45 percent were nulliparous, 12 percent were
nonpregnant primiparous and multiparous, and
44 percent were pregnant (tables A- 12 and
A- 13). The youngest pregnant females taken
were three primiparous 5-year-olds.

Pregnancy rate;.- -The nunaber of female
seals (and the percentage pregnant) collected
in the eastern Pacific from 1958 to 1965 are
shown in table 4; records for 1965 are given
by area and month in table A- 14.

Data on pregnancy rates are necessary for
making population estimates and for deter-
mining the effects of a reduction in size of the
herd. For example, the low pregnancy rates
of 3- and 4-year-old females may increase
now that killing of females on the Pribilof
Islands has reduced the herd to the approxi-
mate level of maximum sustained yield. Preg-
nancy rates representative of the population
cannot be accurately determined from animals
taken on the Pribilof Islands because the
females segregate by reproductive condition
when on land (Roppel, Johnson, Anas, and
Chapman, 1965). Therefore, knowledge of vari-
ation in rates among females taken at sea, by
year, season, and area, is important as a basis
for determining pregnancy rates representa-
tive of the total population.

Regardless of area or season of collection,
the total annual samples show little variation
in pregnancy rates among females in ages

7-13 during the period 1958-65. The variation
increased among 6-year-old females, and at
age 5 the pregnancy rate in different years
ranged from 21 to 56 percent (mean 39 per-
cent). These variations are unexplained.

Uterine horn of conception and fetal sex
ratio.-- The uterus of the female fur seal is
bicornuate. One uterine horn carries a con-
ceptus one year and the other horn carries a
conceptus the following year unless the fennale
fails to conceive one or nr^ore years. Exannina-
tion of 5,057 pregnant females collected since
1958 shows that 5 1 .3 percent of the fetuses were
carried inthe left uterine horn. This difference,
together with the necessity of alternating horns
in order to conceive each year, means thatthe
first conception, or conceptions that occur fol-
lowing an interruption, nnust be nnost frequently
in the left uterine horn.

Of 4,369 fetuses collected in 1958-65, 49.2
percent were males and 50.8 percent were
females.

Attached Organisms (Commensals)

Algae and gooseneck barnacles are com-
monly found on the guard hairs of seals that
have been at sea for an extended period. Of
270 seals collected off California in 1965,
algae were attached to the guard hairs of 42.2
percent, barnacles 33.3 percent, and both
algae and barnacles on 18.1 percent (table 5).
The amount of algae ranged from a few spots
to almost complete coverage of the animal.

-Number of female seals collected pelagically by the U. S A. in the eastern
Pacific and {in parentheses) percentage pregnant, 1958-65

1958

1959

1960

1961

1962

1964

1965

1958-65
combined

15
16

19

39
U-b)

42
(2.4)

70
(45.7)

99
(80.8)

103
(89.3)

102
(89.2)

81
(96.3)

97
(87.6)

113
(92.0)

134
(82.0)

110
(82.7)

92
(81.5)

71
(78.9)

56
(78.6)

36
(55.6)

22
(59. 1)

14
(28.6)

3
(33.3)

1
(100. 0)

22
23

24

26
Total

6-26
years

(0.0)

1. 286
(76. 1)

1, 135
(83.3)

43
(0.0)

93
(6.4)

114
(56. 1)

118
(77.1)

143
(76.2)

164
(86.6)

108
(88.9)

96
(85.4)

98
(89.8)

76
(88.2)

56
(89.3)

70
(84.3)

87
(88.5)

69
(75.4)

36
(80.6)

27
(85.2)

16
(81.3)

5
(40. 0)

7
(85.7)

5
(40.0)

1
(0.0)

(0.0)

(0.0)

1, 434
(73.8)

1, 184
(83.4)

18
(0.0)

36
(2.8)

55
(49.1)

45
(80. 0)

66
(78.8)

105
(85.7)

144
(92.4)

129
(91.5)

136
(91.2)

106
(90.6)

120
(87.5)

107
(80.4)

67
(83.6)

53
(71.7)

46
(67.4)

23
(82.6)

19
(57.9)

6
(16.7)

6
(50.0)

(0.0)

(0.0)

1, 289
(79.7)

1, 180
(84. 4)

84
(0.0)

96
(1.0)

68
(20.6)

62
(75.8)

95
(75.8)

107
(79.4)

114
(93.9)

112
(93.8)

82
(89.0)

71
(93.0)

76
(82.9)

67
(92.5)

68
(79.4)

55
(85. 5)

24
(62.5)

25
(64. 0)

10
(50.0)

(100. 0)

2
(50.0)

(0.0)

(0.0)

1, 227
(68.5)

979
(84.3)

93
(1. 1)

140
(2.9)

123
(26.0)

72
(54.2)

93
(84.9)

98
(89.8)

73
(83.6)

100
(89.0)

91
(89.0)

97
(89.7)

58
(94.8)

65
(87.7)

53
(81. 1)

50
(82. 0)

44
(72.7)

25
(72.0)

15
(60.0)

11
(72.7)

(100. 0)

3
(66.7)

(0.0)

1, 308
(63.4)

952
(83.2)

53
(0.0)

113
(7. 1)

162
(43.8)

90
(74.4)

77
(88.3)

87
(97.7)

60
(85.0)

72
(93, 1)

(94. 3)

92
(92.4)

76
(90.8)

57
(80.7)

75
(85. 3)

45
(82.2)

28
(71.4)

12
(58.3)

5
(60,0)

11
(45.5)

4
(50.0)

2
(0.0)

1, 209
(69.3)

881
(86.0)

74
(0.0)

62
(1.6)

84
(35.7)

81
(75.3)

44
(77.3)

46
(84.8)

30
(83.3)

49
(87.8)

42
(85.7)

51
(84. 3)

33
(84.8)

38
(76.3)

41
(65.9)

22
(72.7)

21
(61.9)

20
(60,0)

7
(57, 1)

10
(20.0)

1
(100, 0)

756
(58.7)

536
(78.9)

51
(0,0)

73
(0.0)

23
(26. 1)

37
(56.8)

24
(79.2)

33
(84.8)

17
(70.6)

10
(90.0)

18
(83,3)

15
(73.3)

(100, 0)

10
(80.0)

14
(78.6)

12
(83, 3)

10
(80. 0)

(37.5)

2
(0.0)

2
(0.0)

(0.0)

(0.0)

369
(45.8)

222
(73.4)

455
(0.4)

655
(3.4)

699
(39.5)

604
(73.2)

645
(81.4)

742
(87.3)

627
(89.8)

665
(89.9)

668
(90.4)

642
(88.0)

537
(87. 3)

506
(83.4)

476
(81.5)

362
(78.7)

245
(68.6)

162
(68.5)

88
(55.7)

55
(47.3)

24
(66.7)

9
(44. 4)

7
(14.3)

4
(0.0)

(0.0)

8,878
(69.6)

7,069
(83.2)

Table 5. — Nunber and percentage of seals collected off California
in 1965 with algae or barnacles growing on guard hairs

Ktonth

Seals
collected

Algae

Barnacles

Algae and
barnacles

Munfcer

46
128
96

Hmiier

13
63
38

Percent

NujAer

7
40
43

Percent

15.2
31.3
44.8

Nui*er

1

27
21

Percent

April

>*y

June

28.3
49.2
39.6

2.2

21.1
21.9

Total

270

lU

42.2

90

33.3

49

18.1

Algae grew most frequently on the throat,
nape, and back. Barnacles were most fre-
quently attached to guard hairs on the ear
pinna, nape, and back. The number of barnacles
found on individual seals ranged from 1 to 42;
size of capitulum ranged from 1 to 1 5 mm.

Algae identified as Ectocarpus spp. were
taken from seals collected in 1964 in the same
area and at the same tinne of year as in 1965.
The algae collected in 1 965 were not identified.

Lepas pectinata pacifica was identified on
85 seals and L. anatifera on 9. Both species
were growing on eight seals. Legas spp. (?)
were found on four seals. Cypris stages of L. p.
pacifica were present on 15 seals.*

Food

Fur seals feed on a variety of fishes and
cephalopods. Reports on the food and feeding
of fur seals in the eastern North Pacific and
Bering Sea were given by: Lucas (1899);
Scheffer (1950); Taylor, Fujinaga, and Wilke
(1955); North Pacific Fur Seal Commission
Report on Investigations from 1958 to 1961
(1964); Fiscus, Baines, and Wilke (1964);
Fiscus, Baines, and Kajimura (1965); and
Fiscus and Kajimura (1965).

In 1965, 416 stomachs taken from seals
collected in waters off Washington (147) and
California (269) were examined: 324 or 78
percent (67 percent off Washington and 84 per-
cent off California) contained food. Of these,
however, 136 contained only trace amounts' of
food (Washington 56, California 80).

Fish and cephalopods found in the stonnachs
of fur seals were identifiedby comparison with
preserved whole specimens and skeletons, and
by using identification keys prepared by An-
driashev (1937, 1954); Berry (1912, 1914);
Clemens and Wilby (1961); Clothier (1950);
Fraser-Brunner (1949); Hitz (1965); Phillips
(1957, 1964); Roedel (1953); Sasaki (1929);
Schultz (1936); and Wilimovsky (1 958).* When-

* Identification of 39 barnacle samples was verified by
Dora P. Henry, Oceanography Department, University of
Washington.

' Trace amount = a stomach containing less than 5 cc.
of food.

' N. J. Wilimovsky. 1958. Provisional keys to the fishes
of Alaska. Bureau of Commercial Fisheries Biological
Laboratory, Juneau, Alaska. 113 p. [Processed manu-
script.]

ever possible, vertebral counts were made to
aid in identification of unknown fish found in
fur seal stomachs. Lengths and weights of
whole fish and squids were measured for use
in studies of size of food species taken and
stomach capacity of fur seals.

New species of fish or squid are added to
the list of fur seal food almost every year.
In 1965, Moroteuthis robusta is reported for
the first time as fur seal food. The major food
species usually remain the same in a given
area, but their rank may change from year to
year and from season to season. Observations
at sea and examination of stomach contents
during the past 8 years (1958-65) show that
fur seals feed primarily between dusk and
dawn. Food species occurring in fur seal
stomachs are shown in figures A- 1 to A- 8.
The detailed results of stomach contents are
shown in tables 6 and 7. Figure 4 shows the
percentage volume and percentage occurrence
of food items that contributed more than 2
percent of the total food volume in each of the
areas.

The numbers of stomachs collected off Cali-
fornia and Washington since 1958 are as
follows:

1958 1959 1961 1964 1965

Washington
California

83
470

230
1,263

382
847

28
305

147
269

The following fishes and cephalopods were
found in fur seal stomachs examined in 1965.
The common and scientific names of fish are
from the list (where applicable) published by
the American Fisheries Society ( 1 960). Cepha-
lopod names are those used by Berry (1912,
1914) and Sasaki (1929).

Lampetra tridentata. Pacific lampreys were
found in the stomachs of five seals collected
off Washington in 1965 (fig. A-1); this species
was also in the stomachs of three seals col-
lected off Grays Harbor, Wash., in 1961.^

Clupeidae. Vertebral fragments of fish be-
longing to this family were in the stomachs
of two fur seals collected off California (fig.
A-2). Pacific herring (Clupea harengus pallasi)
were identified in the stomachs of four seals
taken off California and in the stomachs of
five taken off Washington (fig. A-3). Pacific
herring is not an important fur seal food off
the California and Washington coasts (North
Pacific Fur Seal Commission, 1964; Fiscus
and Kajimura, 1965).

Engraulis mordax. Northern anchovy ranked
third in total food volume and fifth in frequency
off California; off Washington it was first in

'Clifford H. Fiscus, Karl Niggol, and Ford Wilke.
1961. Pelagic fur seal investigations, California to
British Columbia, 1961. Bureau of Commercial Fish-
eries, Marine Mammal Biological Laboratory, Seattle,
Wash. [Processed, 87 p.]

10

Table 6.— Stomach contents of fur seals collected off California, 1965-^

Spring

Summer

Food

April-May

June

Volume

Frequency

Volume

Frequency

Volume

Frequency

Fish:

Co.

47

10,686

5

2,857

36,049

710

11,085

645
143

T

25,507

2,386

129

129

5

T

57
258
T

320
T

Percent

0.1
11.7

0.0

3.1
39.6

0.8
12.2

0.7
0.2

28.0
2.6

0.1
0.1
0.0

0.1
0.3

0.4

Hunter

4
26

1

7
49

4
33

2

41

1

60
34

1

5
16
13

2

1

2

2

1

Cc.

5

6,003

433
4,653
2,953
1,810
1,294

14

2,104
525

T

T
46
240
116

T

Percent

0.0

29.7

2.1

23.1

14.6

9.0

6.4

0.1

10.4
2.6

0.2
1.2
0.6

MuJTiber

2

13

7
21
11
12

3

40

25
15

1
9
4
2
1
5

Co.

5

47

16,689

5

3,290

40,702

3,663

12,895

1,294

645

157

T

27,611

2,911

129

129

5

46

297

374

T

320

T

Percent

0.0
0.0

15.0
0.0
3.0

36.7
3.3

11.6
1.2
0.6
0.1

24.8
2.6
0.1

0.1
0.0
0.0
0.3
0.3

0.3

Number
2

Clupea harengus pallasi..

4
39

1

Merluccius productus

Trachurus synmetricus. . . .

70
15
45

Anoplopoma fimbria

3

2

Unidentified fish

Octopus:

81

1

Squid:

Loligo opalescens *

Onychoteuthis banksii,...
Moroteuthis robusta

85

49

1

6

25

17

4

Gonatopsis borealis

Unidentified squid

2
7
2

1

91,018

145
28

100.0

20, 196

81
15

100.0

111, 214

226
43

100.0

Stomachs with food

173

96

269

■"■ T = trace, (< 5 cc). Trace counts are included in frequency counts.

volume and second in frequency. Seals taken
off Monterey, Calif., and Grays Harbor, Wash.,
had fed on anchovy (fig. A-4).

Oncorhynchus spp, Salmon had been eaten
by seven seals collected off Grays Harbor and
by one taken off Cape Flattery, Wash. (fig.
A- 5). One stomach contained coho salmon,
O. kisutch (1-year ocean growth), and another
a chinook salmon, O. tshawytscha (2- year
ocean growth).' Salmon ranked third in total
food volume and fourth in frequency of occur-
rence; it was not found in the stonnachs of
seals collected off California.

Thaleichthys pacificus. Eulachon ranked
second in volume and third in frequency off
Washington. Nine of eleven occurrences were
from seals taken off Cape Flattery (fig. A- 3).

Myctophidae. A lanternfish was eaten by a
fur seal collected in lat. 37° 49' N,, long.
124° 11' W. (fig. A- 1). Specific identification
could not be made because many identifying
photophores were missing. Lanternfishes are
a minor food item of fur seals collected in the

' The salmon were identified from scales by Raymond
E. Anas, Bureau of Commercial Fisheries, Marine Mam-
mal Biological Laboratory, Seattle, Wash.

eastern Pacific Ocean, although they are the

principal food of fur seals off Japan in spring.

Cololabis saira. Pacific saury (fig. A-6)

ranked sixth in importance as a food species

Table 7 Stomach contents of fur seals collected off Washington, 1965

Spring

Food

April

Volume

Frequency

Fish:

Lampetra tridentata

Clupea hareneus pallasi...

Cc.l

863

1,311

6,717

1,590

2,506

T

613

244

30

10

33
T
T
T
T

Percent

6.1

9.3

47.6

11.3

17.7

5.8

1.7
0.2
0.1

0.2

Number

6

5

20

Oncorhynchus spp

Thaleichthys pacificus

Merluccius productus

Gasterosteus aculeatus. . . .

8
11

1
7

1

Anoplopoma fimbria

Unidentified fish

Squid :

1
39

21

2

Unidentified squid

2

Pebbles

Organic material

3
2

Total

Stcoiachs with food

Stomachs empty

K,117

98
49

100.0

li7

^ T=trace, (< 5 cc. ). Trace counts are included in frequency counts.

U

Li.

<

o
o

X

<

SQUIDS

SEBASTODES SPP.
TRACHURUS SYMMETRICUS
MERLUCCIUS PRODUCTUS
COLOLABIS SAIRA
ENGRAULIS MORDAX

i^^X>N«i»K»:'^MVi^M!CC««CCCW«

■N>.N\.\.N-\XV\-\M

^^^W!^^mW.v^v^v.vv^

GASTEROSTEUS ACULEATUS
THALEICHTHYS PACIFICUS
ONCORHYNCHUS SPP
ENGRAULIS MORDAX
CLUPEA HARENGUS PALLASI
LAMPETRA TRIDENTATA

^^^^^

^^■>-'^-N-^N-<Vn

^■■occurrence
g^^^ volume

VVVVM

10

20

30 40

PERCENT

50

60

70

Figure 4. — Percentage of stomach content volume and percentage occurrence of principal food species in fur seal

stomachs, by area, In 1965.

off California. Sixty-three saury formed 53
percent of the total volume in one stomach.
Lengths of four specimens ranged from 21 to
27 cm.

Merluccius productus. Pacific hake occurred
in the stomachs of 70 fur seals collected off
California and 1 off Washington (fig. A-7).
It ranked first in total volume of food (36.7
percent) and second in frequency off California,
where it also had been a major food item in
past years. At times fur seals were feeding
mostly on hake near the Farallon Islands and
off Monterey, Calif.; one stomach contained
the remains of 31.

Gasterosteus aculeatus. Threespine stickle-
backs occurred in the stomachs of seven fur
seals collected off Cape Flattery, Wash,, and
formed 5.8 percent of the total food volume.
The one previous occurrence in fur seal
stomachs was in 1959 from the same general
area (fig. A-6). Canadian biologists have fre-
quently found this species in the stomachs of
seals taken off Vancouver Island (North Pacific
Fur Seal Commission, 1964).

Trachurus symmetricus. Jack mackerel
ranked fifth in volume of food (3.3 percent) off
California and were found in 1 5 stomachs (fig.
A-1).

Sebastodes spp. Rockfish ranked fourth in
both volume (11.6 percent) and frequency (45)
off California. All rockfish from California
were juveniles (vertebral length from 47 to 99
mm.). They were most numerous in stomachs
from seals collected off Monterey (fig. A- 8).
One stomach contained 137 small rockfish.
Adult rockfish (according to size of vertebrae)
occurred once in the stomach of a fur seal
collected off Washington.

Anoplopoma fimbria. Sablefish were found
in three fur seals collected off California and
one off Washington (fig. A- 8). They have been

a minor food of seals off California and Wash-
ington (North Pacific Fur Seal Commission,
1964; Fiscus and Kajimura, 1965).

Pleuronectidae. Flatfish of this family were
in two seals collected off California (fig. A-6).

Tremoctopus sp. The remains of a small
pelagic octopus was in the stomach of a seal
collected off California in lat. 38 00' N., long.
124° 35' W. (fig. A-6). This octopus was found
in the stomachs of 28 seals collected south of
Pt, Sur, Calif, in 1961.'

Squids, Squids are one of the main foods of
fur seals in the eastern North Pacific. They
ranked first in frequency of occurrence off
both California (196) and Washington (26); and
second in total food volume off California
(28.2 percent) and eighth off Washington (0.2
percent). Squid bodies are easily digested by
fur seals. Squid beaks and pens, which are not
digested and remain in the stomachs long after
the bodies are digested, are listed as trace
amounts when no body fragments remain.

The following squids from fur seal stomachs
were identified: Loligo opalescens, Onycho-
teuthis banksii, Moroteuthis robusta, Abraliop-
sis sp., Gonatus fabricii, G. magister, and
Gonatopsis borealis (figs. A-1 to A-5).

L. opalescens ranked first in frequency of
occurrence and second in total volume of food
off California (first in total volume among
squids). Most of these squids were found in
the stomachs of seals collected off Monterey,
the Farallon Islands, and Pt. Reyes, Calif.;
it ranked first in frequency of occurrence off
Washington.

O. banksii occurred in the stomachs of 49
seals collected off California and ranked second
in importance among squids. One stomach
contained the remains of eight squids.

' See footnote 7.

12

The remains of M. robusta were found in
the ston^ach of a fur seal collected about 25
miles west of the Farallon Islands on 21 May
1965. This is the second specimen identified
from fur seal stomachs. The first, also taken
off California, was obtained in 1961 but not
identified until comparative material became
available in 1962.

M. robusta is an important food of sperm
whales off central California (Rice, 1963), but
because of its large size is probably not regu-
larly eaten by fur seals. The cartilaginous end
cone of the pens from two whole specimens in
our reference collection approximated one-
fourth of their dorsal mantle length (DML).
The end cone found in 1 965 measured 1 50 mm.,
indicating a DML of about 600 mnn. A squid of
this size cannot be swallowed whole. Frag-
ments of flesh were found in addition to the
end cone. Beaks or additional parts of the pen
were not found.

Abraliopsis sp. was of minor importance
(seven occurrences) in 1965. Two stomachs
contained fragments and beaks of 70 and 97
squids each. This squid was in stomachs of
seals collected in the same general area in
1961.'"

Three gonatids identified in 1965 were:
Gonatus fabricii (California 17, Washington 2);
G. magister (California 4); and Gonatopsis
borealis (California 2).

Miscellaneous. Unidentified bird feathers
were in the stomachs of two fur seals collected
off California (the volume of feathers in one
was 320 cc.) and in one collected off Wash-
ington. Other items were: pebbles (4-6 mm.
diam.) in three stomachs; small fragments of
wood (largest 1 cm. by 1 cm.) in two stomachs;
and a piece of kelp in one stomach.

Relation of Fur Seals to Commercial
Fisheries

The effect of predation by fur seals on
various species of commercially important
fishes and cephalopods cannot be determined
without adequate knowledge of the distribution
and abundance of each prey species, the extent
to which these species are utilized by other
predators, and the extent to which other
predators of the prey species are removed
by fur seals. Detailed knowledge of the ocean
environment and its influence on fish popula-
tions is also needed if the effects of fur seals
on commercially important species of fish are
to be accurately appraised. Data collected to
date indicate that fur seals feed heavily on
the most readily available fishes or cepha-
lopods.

To show the degree to which fur seals use
con-imercially important fishes off California,
the species found in the stomachs may be
compared with those that support the fishery.

'" See footnote 7.

The 10 leading fish and shellfish in the Cali-
fornia commercial fishery, listed in the order
of pounds landed in 1963 (California Depart-
ment of Fish and Game, 1965), were: Tra-
churus symmetricus (jack mackerel); Thunnus
alalunga (albacore); Scomber japonicus [diego]
(Pacific mackerel); Loligo opalescens (squid);
all species of Sebastodes and Sebastolobus
(rockfish); Microstomus pacificus (Dover sole);
Oncorhynchus kisutch and O^, tshawytscha (sal-
mon); Sardinops sagax (sardine); Thunnus
thynnus (bluefin tuna); and Engraulis mordax
(northern anchovy). Four of the ten commer-
cially important species were found in fur
seal stomachs: jack mackerel (3.3 percent of
the total food volume in seal stomachs), squid
(24.8 percent), rockfish (11.6 percent), and
northern anchovy (15.0 percent). Almost no
fishing for these species, however, is done in
the offshore waters where fur seals feed.
Pacific hake, which formed 36.7 percent of the
total food volume in seal stomachs, are of
little commercial value in California.

The most important connmercial fish taken
by fur seals collected off Washington were
salmon, which occurred in 8 of 147 stomachs.
Off Grays Harbor, Wash., fur seals were com-
mon in an area where salmon troUers were
fishing.

No valid conclusion about the relation of fur
seals to commercial fisheries can be drawn
from the data available. Considering the vol-
ume and frequency of occurrence of commer-
cially important food species in fur seal
stomachs examined in 1965, predation by fur
seals on commercial species of fish is not a
cause for alarm.

SUMMARY

The United States has conducted pelagic
research on fur seals since 1958 in coopera-
tion with Canada, Japan, and the U.S. S.R. under
the terms of the Interim Convention on Con-
servation of the North Pacific Fur Seals. In
1965, observations and collections were made
off Washington 2-24 April and off central
California 11 April to 23 June, by two char-
tered purse seine vessels.

Seals were widely scattered off Cape Flat-
tery, Wash,, in early April, but a concentra-
tion was located off Grays Harbor, Wash., in
mid-April. Of 147 seals taken off Washington,
only 19 were males. In California waters,
seals were most numerous off Monterey and
near Cordell Bank west of Pt. Reyes; 1 0 of 269
collected were males.

To study distribution and migration of fur
seals off California, transect lines extending
10 to 80 miles offshore were established at
20-mile intervals between Bodega Head and
Pt. Sur. Seals were counted along these lines
each month. Seals were most abundant 30 to
40 miles offshore, and decreased gradually
out to 80 miles.

13

The number of seals seen off California
decreased from April to June as a result of
the northward nnigration of pregnant seals.
This decrease was not apparent off Washington
in April when the survey ended near the peak
of migration.

As in other years, males fornned only a
small proportion of the total number of fur
seals wintering off California.

Twenty tagged seals (including seven that
had lost their tags) were collected in 1965.

Of 387 females collected in 1965, 45 percent
were nulliparous, 12 percent were nonpregnant
primiparous or multiparous, and 44 percent
were pregnant. Three primiparous 5- year- olds
were the youngest pregnant seals taken.

Data collected since 1958 on 5,057 pregnant
females show that 51.3 percent of the preg-
nancies occurred in the left uterine horn; the
first pregnancy occurs more frequently in
that horn.

Male and female fetuses were about equally
represented (50.8 percent females) in 4,369
fetuses.

Algae were found growing on guard hairs of
114 seals (42.2 percent), and gooseneck bar-
nacles on guard hairs of 90 seals (33.3 per-
cent) collected off California in 1965.

In a given area, the major food species of
fur seals usually rennain the same, but their
rank may change from year to year and season
to season.

A squid, Moroteuthis robusta. was recorded
for the first time as fur seal food.

Merluccius productus and Loligo opalescens
were the major food species (by volume) in
stomachs of fur seals taken off California.

Engraulis mordaxand Thaleichthys pacificus
were the major food species off Washington.

Miscellaneous objects in fur seal stomachs
included bird feathers, pebbles, small frag-
ments of wood, and kelp.

The volume and frequency of occurrence of
commercially important food species in fur
seal stomachs give no cause for alarnn about
predation on commercial species of fish.

LITERATURE CITED

ABEGGLEN, CARL E., and ALTON Y, ROP-
PEL.

1959. Fertility in the northern fur seal,
1956-57. J. Wildl. Manage. 23(1): 75-81.

AMERICAN FISHERIES SOCIETY.

1960. A list of common and scientific names
of fishes from the United States and
Canada. 2d ed. Its Spec. Publ. 2,
102 p.

ANDRIASHEV, ANATOLY P.

1937. K. poznaniyu ikhtiofauny Beringova i
chukotskogo morei. Inst. Hydro., Len-
ingrad, Explor. Mers URSS, fasc. 25:
295-355. (A contribution to the knowl-
edge of the fishes fronn the Bering Sea
and Chukchi Seas. Translated by Lisa

Lanz and Norman J. Wilimovsky, Fish
Wildl. Serv., Spec. Sci. Rep. Fish. 145,
ii + 81 p., 1955.)
1954. Ryby severnykh morei SSSR. Izda-
tel'stvo Akademii Nauk SSSR, Moskva-
Leningrad. (Fishes of the northern seas
of the U.S.S.R. Translated by Michael
Artman, Israel Program for Scientific
Translations, 617 p., 1964, OTS 63-
11160.)
AUSTIN, O. L., and FORD WILKE.

1950. Japanese fur sealing. General Head-
quarters, Supreme Commander for the
Allied Powers, Natural Resources Sec-
tion, Rep. 129, 91 p. [Reproduced as
Fish Wildl. Serv., Spec. Sci. Rep, Wildl.
6, 1950.]
BERRY, S. S.

1912, A review of the cephalopods of west-
ern North America. U.S. Bur. Fish.
Bull. 30: 267-336.
1914. The cephalopods of the Hawaiian Is-
lands. U.S. Bur. Fish., Bull. 32: 257-
362.
CALIFORNIA DEPARTMENT OF FISH AND
GAME.
1965. The California marine fish catch for

1963. Its Fish Bull. 129. 45 p.
CLEMENS, W. A., and G. V. WILBY.

1961. Fishes of the Pacific Coast of Canada.
Fish, Res. Bd. Canada, Bull. 69, 2d ed.
368 p.
CLOTHIER, CHARLES R,

1950, A key to some southern California

fishes based on vertebral characters.

Calif. Div. Fish Game, Fish Bull. 79,

83 p.

FISCUS, CLIFFORD H., GARY A. BAINES,

and FORD WILKE.

1964. Pelagic fur seal investigations, Alas-
kan waters, 1962. U.S. Fish Wildl, Serv.,
Spec. Sci. Rep. Fish. 475, iii + 59 p.

FISCUS, CLIFFORD H., GARY A. BAINES,
and HIROSHI KAJIMURA.

1965. Pelagic fur seal investigations,
Alaska, 1963. U.S. Fish Wildl, Serv.,
Spec. Sci. Rep. Fish. 489, iv + 33 p.

FISCUS, CLIFFORD H,, and HIROSHI KAJI-
MURA.
1965. Pelagic fur seal investigations,

1964. U.S. Fish Wildl. Serv., Spec. Sci.
Rep. Fish. 522, v + 47 p.

FRASER-BRUNNER, A.

1949. A classification of the fishes of the
family Myctophidae. Proc. Zool. Soc,
London 118(4): 1019-1106, 1 pi.
HITZ, CHARLES R.

1965. Field identification of the northeast-
ern Pacific rockfish (Sebastodes). U.S.
Fish Wildl. Serv., Circ. 203, 61 p.
JORDAN, DAVID STARR.

1899. The fur seals and fur-seal islands of
the North Pacific Ocean. U.S. Treas.
Dep., Doc. 2017 (1): 17. 142, 153, 165,
173; (2): 59. 223, and 285.

1'

the rockfishes of Cali-
Dep, Fish Game, Fish

LUCAS, FREDERIC A.

1899. The food of the northern fur seals.
In The fur seals and fur seal is-
lands of the North Pacific Ocean. U.S.
Treas. Dep., Doc. 2017(3): 59-68, pis.
12-15.
NIGGOL, KARL.

1960. Early mortality in fur seals according
to sex. J. Wildl. Manage. 24(4): 428-
429.
NORTH PACIFIC FUR SEAL COMMISSION.
1964. North Pacific Fur Seal Com-
mission report on investigations from
1958 to 1961. Kenkyusha Co., Tokyo,
183 p.
PHILLIPS, JULIUS B.
1957. A review of
fornia. Calif.
Bull. 104, 158 p.

1964. Life history studies on ten species of
rockfish (genus Sebastodes). Calif . Dep.
Fish Game, Fish Bull. 126, 70 p.

RICE, DALE W.

1963. Progress report on biological studies
of the larger Cetacea in the waters off
California. Norsk Hvalfangst- Tid. 1963
(7): 181-187.
ROEDEL, PHIL M.

1953. Common oceanfishes of the California
coast. Calif. Dep. Fish Game, Fish Bull.
91, 184 p.
ROPPEL, A. Y., A. M, JOHNSON, R, E. ANAS,
and D. G. CHAPMAN.

1965. Fur seal investigations, Pribilof Is-
lands, Alaska, 1964. U.S. Fish Wildl.
Serv., Spec. Sci. Rep. Fish. 502, v +
46 p.

SASAKI, MADOKA.

1929. A monograph of the dibranchiate
cephalopods of the Japanese and adjacent
waters. J. Fac. Agr., Hokkaido Imp.
Univ., Sapporo, 20, suppl., 367 p., 30

pis.
SCHEFFER,
1950. The

Trans.
SCHULTZ, L

VICTOR B.
food of the Alaska fur seal.
15th N. Amer. Conf.: 410-421.
P.

1936. Keys to the fishes of Washington,
Oregon, and closely adjoining regions.
Univ. Wash., Publ. Biol. 2(4): 1 03-228.
SWAN, JAMES G.

1883. Report of investigations at Neah Bay,
Wash., respecting the habits of fur seals
of that vicinity, and to arrange for pro-
curing specimens of skeletons of Ce-
tacea. U.S. Fish Comm., Bull. 3: 201-
207.
TAYLOR, F. H. C, M. FUJINAGA, and FORD
WILKE.
1955, Distribution and food habits of the fur
seals of the North Pacific Ocean. U.S.
Dep. Interior, Fish Wildl. Serv., Wash-
ington, D.C., 86 p.
TOWNSEND, C. H.

1898, Deposition of: in letters and state-
ments of naturalists [regarding fur
seals]. In D, S. Jordan, Seal and salmon
fisheries and general resources of
Alaska, H, Doc, 92, pt. 1 to 4, 55th
Cong., p, 51-53.
WILKE, FORD, and KARL W, KENYON,

1957, The food of fur seals in the eastern
Bering Sea. J, Wildl. Manage. 21(2):
237-238.

15

APPENDIX A

Table A-1. — Distribution and migration studies: seals observed along transects, 1965
no observations; 0 = no seals observed. The transect in lat. 36*^ 20' N. was not run in May.

Transect

Distance

38^

00'

N.

37° 40'

N.

37° 20'

N.

37

° 00'

N.

36° 40'

N.

36°

20' N.

Total

seals

observed

per

from
shore

Date

16

13

U

17

12

U

18

11-12

16

19

11

16-17

20

10

18

21

18-19

unit

Apr.

May

June

Apr.

May

June

Apr.

May

June

i^r.

May

June

Apr.

May

June

Apr.

June

Miles

No.

No.

No.

No.

No.

No.

No.

No.

No.

No.

No.

No.

No.

No.

No.

No.

No.

No.

0-10

_

_

_

_

_

_

_

.

.

.

.

0

.

.

0

0

0

10-20

16

0

0

1

-

-

0

0

0

0

4

2

0

0

0

1

1

25

20-30

12

3

1

1

-

0

4

1

0

7

7

2

1

4

0

6

3

52

30-AO

10

20

■;

11

0

0

2

0

3

9

8

5

41

12

0

9

0

134

40-50

19

2

2

28

1

7

2

2

11

4

8

0

2

1

1

1

1

92

50-60

13

1

6

5

1

4

2

2

1

7

3

1

14

14

0

2

0

76

60-70

11

3

-

5

3

14

7

9

-

1

0

3

8

10

0

1

0

75

70-80

-

-

-

-

9

0

0

1

-

1

0

-

-

-

-

-

0

11

Total

81

29

13

51

U

25

17

15

15

29

30

13

66

41

1

20

5

465

Total seals observed : 16-21 April--264
10-13 May 129
14-19 June 72

Table A-2. — Number and relative abundance of seals seen, by 10-day periods, off California and

Washington, 2 April to 23 June 1965

Area and period

Boat-hunting
days'"-

Total seals
seen

Seals seen per
boat-hunting day

Seals seen per
10-day interval

Number

Number

Number

Percent

California:

Apr. :
11-20

7.25

337

46.5

30.3

21-30

4.00

106

26.5

9.5

May:

1-10

3.75

117

31.2

10.5

11-20

5.25

139

26.5

12.5

21-31

8.00

182

22.8

16.3

June:

1-10

6.00

106

17.7

9.5

11-20

5.75

91

15.8

8.2

21-30

3.00

36

12.0

3.2

Total

43.00

1,114

25.9

100.0

Washington :
Apr. :
1-10

8.75

110

12.6

21.4

11-20

4.00

147

36.8

28.7

21-30

4.00

256

64.0

49.9

Total

16.75

513

30.6

100.0

All regions:
Total

59.75

1,627

A boat-hunting day is a day in which a vessel is \ised for 8 hours or more; units of boat-
hunting days are 0.25, 0.50, 0.75, and 1.00.

16

Table A-3.— Number and relative abundance of seals collected, by 10-day periods, off California

and Washington, 2 April to 23 June 1965

Boat-hunting
days-"-

Seals collected

Seals collected per

Area and period

Males

Females

Total

boat-hunting day

California:
Apr. :
11-20
21-30
May:
1-10
11-20
21-31
June:
1-10
11-20
21-30

Number

3.75
3.00

3.50
2.75
8.00

6.00
2.50
3.00

Number
2

3

1
1

1
2

Number

26

18

23
23
77

64

5

24

Number

28
18

26

24
78

65

7

24

Number

7.5
6.0

7.4
8.7
9.8

10.8
2.8
8.0

Percent

10.4
6.7

9.6

8.9

28.8

24.1
2.6
8.9

Total

32.50

10

260

270

8.3

100.0

Washington:
Apr. :
1-10
11-20
21-30

8.75
4.00
4.00

11
6
2

21
41
68

32
47
70

3.7
11.8
17.5

21.5
31.5
47.0

Total

16.75

19

130

149

8.9

100.0

All regions :
Total

49.25

29

390

419

■"• A boat-hunting day is a day in which a vessel is used for 8 hours or more; units of boat-
hunting days are 0.25, 0.50, 0.75, and 1.00.

Table A-4.— Number of seals per group among 1,627 seals sighted off California and Washington,

2 April to 23 June 1965

Num

ber of

seals in group

Total

Area

1

2

3

4

5

6

7

8

9

California:

Number of groups

563

132

53

18

7

1

1

1

—

776

Number of seals

563

264

159

72

35

6

7

8

--

1,114

Percent of seals

50.6

23.7

14.3

6.5

3.1

0.5

0.6

0.7

0.0

100.0

Washington :

Number of groups

162

65

26

12

8

5

1

—

2

281

Number of seals

162

130

78

48

40

30

7

--

18

513

Percent of seals

31.6

25.3

15.2

9.4

7.8

5.8

1.4

0.0

3.5

100.0

Combined Areas :

Number of groups

725

197

79

30

15

6

2

1

2

1,057

Number of seals

725

394

237

120

75

36

14

8

18

1,627

Percent of seals

44.5

24.2

14.6

7.4

4.6

2.2

0.9

0.5

1.1

100.0

17

Table A-5. --Monthly mean lengths of pregnant fur seals collected pelagically by
the U.S.A. in the eastern Pacific in 1965

Ap

ril

May

Ju

ne

Com

bined length

Age

Mean

Mean

Mean

Mean

Standard

Seals

length

Seals

length

Seals

length

Seals

length

deviation

Years

Number

Cm.
120.0

Number

1

Cm.
120.0

Number

1

Cm.
124.0

Number
6

Cm.

120. 7

Cm.

5

4

3.0

6

14

118.6

4

123.0

3

126. 3

21

120.6

4.5

7

11

124.4

4

122.8

4

128.8

19

125.0

3.5

8

16

126.8

9

123.4

3

130.3

28

126. 1

4.5

9

4

125.5

4

126.5

4

126.7

12

126.2

3.2

10

4

127.8

2

128.5

3

126. 3

9

127.4

3. 1

11

6

125.0

6

129.0

3

127.3

15

127. 1

5.8

12

4

130.8

5

126.2

2

130.0

11

128.5

4.6

13

1

117.0

3

130.0

4

130.8

8

128.8

6.3

14

2

133.0

5

130.0

1

134. 0

8

131.2

5.2

15

1

129. 0

7

130.8

3

123.3

11

128.6

4.6

16

3

133.0

4

129.2

3

127. 0

10

129. 7

3.9

17

3

130.7

5

132.2

-

-

8

131.6

3.0

18

1

126.0

1

134.0

1

129.0

3

129.7

4.0

Total

74

60

35

169

Table A-6. -■

Monthly mean weights of pregnant fur seals collected pelagically
by the U.S.A. in the eastern Pacific in 1965

April

May

June

Combined weight

Age

Seals

Meaji
weight

Seals

Mean
weight

Seals

Mean
weight

Seals

Mean
weight

Standard
deviation

Years

Number

29.8
31.2
35.6
34.4
36.2
39.5
37.3
43.5
33.0
44.5
43.0
43. 3
45.0
44.0

Number

1
4
4
9
4
2
6
5
3
5
7
4
5
1

Kg.

26.0
39.0
37.2
38.6
39.2
46,0
46.3
43.6
47.7
48.8
49.0
47.0
52.6

56.0

Number

1
3
4
3
4
3
3
2
4
1
3
3

1

31.0
41.3
43.2
42.7
42.5
43.3
44.0
48.0
49. 0
57.0
46.7
46.3

48.0

Number

6

21

19

28

12

9

15

11

8

8

11

10

8

3

29.3
34. 1
37.6
36.6
39.3
42.2
42. 3
44.4
46.5
48.8
47.8
45.7
49.8
49.3

Kg.

5

6

7

8

9

10

11

12

13

14

15

16

17

18

4

14
11
16
4
4
6
4
1
2
1
3
3
1

3.4
5. 1
4.4
4.4
3.8
3.7

5. 1
5.6
6.4
5.6
4. 1
4.2
5.7

6. 1

Total

74

60

35

169

18

Table A-7. --Monthly mean lengths of nonpregnant female fur seals collected
pelagically by the U.S.A. in the eastern Pacific in 1965

April

May

June

Combined length

Age.

Mean

Mean

Mean

Standard

Seals

length

Seals

length

Seals

length

Seals

Mean

deviation

Years

Number

Cn-i.

Number

Cm.

Number

Cm.

Number

Cm.

Cm.

1

7

76.6

3

77. 0

-

-

10

76.7

2. 9

2

5

89. 6

2

93. 0

1

96. 0

8

91.2

2. 9

3

23

99.9

11

101.4

17

103. 0

51

101. 3

3.7

4

33

109.4

21

110.0

19

110.8

73

109. 9

4. 1

5

6

117. 0

5

110.0

6

118. 0

17

115. 3

5.8

6

9

117. 2

3

115.7

4

120. 0

16

117.6

4. 7

7

3

122. 0

1

120. 0

1

125. 0

5

122.2

4.6

8

1

122. 0

-

4

125.8

5

125. 0

5.2

9

2

121. 5

1

116.0

1

118.0

4

119. 2

3.4

10

1

117. 0

1

134.0

-

-

2

125. 5

12.0

11

1

129. 0

-

-

-

-

1

129. 0

0.0

12

1

118. 0

2

130.5

-

-

3

126. 3

7.6

13

-

-

1

125. 0

1

129.0

2

127. 0

2.8

14

1

131.0

2

125. 5

-

-

3

127. 3

3. 5

15

-

-

1

123.0

-

-

1

123.0

0.0

16

1

121. 0

-

-

1

124. 0

2

122. 5

2. 1

17

1

131. 0

2

130. 5

2

124. 0

5

128.0

4.6

18

1

126.0

1

133.0

-

-

2

129. 5

4.9

19

-

-

3

130.7

-

-

3

130. 7

2.9

20

1

125. 0

-

-

1

135. 0

2

130. 0

7. 1

21

-

-

2

128. 5

-

-

2

128. 5

3. 5

23

_

_

1

128. 0

_

_

1

128.0

0. 0

Total

97

63

58

218

19

Table A-8. --Monthly mean weights of nonpregnant female fur seals collected pelagically

by the U. S. A. in the eastern Pacific in 1965

April

Ma

y

June

Connbined weights

Mean

Mean

Mean

Standard

Age

Seals

weight

Seals

weight

Seals

weight

Seals

Mean

deviation

Years

Number

Kg.

Number

Kg.

Number

Kg.

Number

Kg.

Kg.

1

7

7.7

3

8.7

-

-

10

8.0

1.6

2

5

12. 4

2

14. 0

1

14. 0

8

13. 0

1.2

3

23

16. 3

11

17. 5

17

17.6

51

17. 3

2.4

4

33

20. 5

21

20.8

19

22. 3

73

21. 0

2. 5

5

6

25. 3

5

22.2

6

26.2

17

24. 7

2. 5

6

9

24. 9

3

25. 3

4

27.2

16

25.6

2. 5

7

3

29. 3

1

28. 0

1

32. 0

5

29.6

1.8

8

1

32. 0

-

-

4

31.8

5

31.8

3. 1

9

2

29.5

1

27. 0

1

26.0

4

28. 0

2. 2

10

1

31. 0

1

46. 0

-

-

2

38. 5

10.6

11

1

32. 0

-

-

-

-

1

32. 0

0. 0

12

1

28. 0

2

37.0

-

-

3

34. 0

5.6

13

-

1

43. 0

1

37. 0

2

40. 0

4. 2

14

1

47. 0

2

36.0

-

-

3

39.7

7. 0

15

-

-

1

32. 0

-

-

1

32. 0

0. 0

16

1

30. 0

-

-

1

36.0

2

33. 0

4.2

17

1

45. 0

2

46. 0

2

38. 5

5

42. 8

5.8

18

1

35. 0

1

45. 0

-

-

2

40. 0

7. 1

19

-

-

3

44. 0

-

3

44. 0

2. 0

20

1

35. 0

-

-

1

49. 0

2

42. 0

9. 9

21

-

-

2

42. 0

-

-

2

42. 0

4.2

23

«

_

1

37. 0

_

_

1

37. 0

0. 0

Total

97

63

58

218

20

Table A-9. --Monthly nneem lengths of male fur seals collected pelagically by the

U.S.A. in the eastern Pacific in 1965

April

May

June

Combined length

Age

Seals

Mean
length

Seals

Mean
length

Seals

Mean
length

Seals

Mean
length

Standard
deviation

Years

Number

Cm.

81.2

95.0

104. 2

118. 5

Number
2

3

Cm.

85.0

110.0

Number
3

Cm.

85.3

Number

11

3
10

5

Cm.

83.0

95.0

104.2

113.4

Cm.

1
2
3

4

6

3

10

2

4.9
4.4
6.7
6.6

Total

21

5

3

29

Table A-10. --Monthly mean weights of male fur seals collected pelagically by the

U.S.A. in the eastern Pacific in 1965

April

May

June

Combined length

Age

Seals

Mean
weight

Seals

Mean
weight

Seals

Mean
weight

Seals

Mean
weight

Standard
deviation

Years

Number

Kg.

9.5
13.0
19.4
27.0

Number
2

3

K£i

13. 0

24.3

Number
3

K£^
12.0

Number

11

3

10

5

Kg-

10.8
13.0
19.4
25.4

iSsi

1
2
3
4

6

3

10

2

2.3
2.6
1.9
1.8

Total

21

5

3

29

Table A- 11. — Monthly mean lengths and weights of fur seal fetuses collected
pelagically by the U.S.A. in the eastern Pacific in 1965

Male

Female

Period

Fetuses

Mean
length

Mean
weight

Fetuses

Jfean
length

Mean
weight

Apr. :
1-10
11-20
21-30

May:
1-10
11-20
21-31

June:
1-10
21-30

Number

5
U
17

6

5

21

21

1

Cm.
AA.3
48.9

55.7
5^.3
57 .'2

59.5
60.0

2.0
2.2
2.6

3.8

3,7

Number

3
15

20

5

7

16

13

Cm.

43.3
43.8
47.1

45.8
52.9
54.5

56.5

Mr

1.7
1.9
2.3

2.8
3.3
3.8

4.2

Total

90

79

21

Table A- 12. -

-Reproductive condition, by month, of female fur seals collected
pelagically by the U.S.A. off California in 1965

Nulliparous

Prlmiparous

Mult

parous

Age

Nonpregnant

Pregnant

Nonpregnant

Pregnant

Total

Years

Number

Number

Number

Percent

April

Number

Number

Percent

Number

1
2

1
3

-

-

-

-

-

1
3

3

3

-

-

-

-

-

-

3

4

6

-

-

-

-

-

-

6

5

2

-

-

-

-

-

-

2

6

2

-

2

100. 0

-

1

100. 0

5

7

_

-

2

100. 0

-

-

-

2

8

_

.

-

-

-

100. 0

1

9

-

-

-

-

2

50.0

4

10

-

-

-

-

-

100. 0

2

1 1

-

-

-

-

-

100.0

4

12

-

-

-

-

-

100. 0

3

13

-

-

-

-

-

100.0

1

14

-

-

-

2

100.0

2

15

-

-

-

-

-

-

-

-

16

-

-

-

-

1

1

50. 0

2

17

-

-

2

100. 0

2

Total

17

-

4

3

19

43

Percent

100.0

May

86.4

1

3

-

.

_

_

_

_

3

2

2

-

-

-

-

-

2

3

1 1

-

-

-

1 1

4

21

-

-

-

-

-

-

21

5

5

-

1

100.0

-

-

-

6

6

1

2

-

-

4

100. 0

7

7

-

1

1

50.0

-

3

100.0

5

8

-

-

1

100. 0

8

100. 0

9

9

-

.

1

4

75.0

5

10

-

.

-

1

2

66.6

3

1 1

-

-

-

-

-

6

100.0

6

12

-

-

-

-

4

5

55.5

9

13

-

.

-

-

-

3

100.0

3

14

.

-

-

-

1

5

83.3

6

15

-

.

-

-

1

7

87.5

8

16

.

-

-

1

4

80.0

5

17

-

.

.

1

5

83. 3

6

18

-

-

-

2

1

33.3

3

19

-

.

-

-

2

-

-

2

20

-

-

-

-

1

-

1

21

-

-

-

-

1

-

1

23

-

-

-

-

1

1

Total

43

3

3

50.0

17

57

77.0

123

June

1
2

3

-

-

1
17

_

.

.

.

_

_

17

4

19

-

-

-

-

-

19

5

6

-

1

100.0

-

-

-

6

4

-

.

-

-

100.0

7

-

1

1

50.0

-

100.0

8

-

1

3

50.0

9

-

-

-

-

1

80.0

10

-

-

-

.

.

100.0

1 1

-

-

-

-

1

75.0

12

-

-

-

-

.

100.0

13

-

-

-

-

-

100.0

14

-

-

-

-

-

100.0

15

-

-

-

-

1

75.0

16

-

.

-

-

-

100.0

17

-

-

.

.

1

.

18

-

.

.

-

2

33.3

20

-

-

-

-

-

-

-

Total

47

2

2

50. 0

9

33

78.6

93

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I. M

o

o

o

d

d

d

d

d

d

d

d

d

d

d

S OJ

vO

o

o

in

o

o

o

O

o

in

o

0- &

"^

'^

"

"^

"^

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"

^^ C

:;1

1 s

a

3 u

o

o

o

fo

fV]

—

(M

fV]

'«•

m

-

fVJ

'

-

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^

fO

vO

rvj

in

fvj

—

^

rg

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fVJ

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rO

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z

4J

W

PO

-^

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sD

r-

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CT-

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>^

rg

fO

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-JD

r-

CO O^ O -H ro 1

^

— '

— '

— '

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— '

— '

-H

-< fM fM fM 1

g

24

Figure A- 1.— Locations where fur seal stomachs collected In 1965 contained the following fishes and
squid (State and number of occurrences in parentheses): Trachurus symmetrlcus (California, 15);
Myctophidae (California, 1); Gonatopsis borealis (California, 2); and Lampetra trldentata (Wash-
ington, 6).

25

Figure A-2. — Locations where fur seal stomachs collected in 1965 contained the following fishes
and squid (State and number of occurrences in parentheses): Clupeidae (California, 2); and
Loligo opalescens (California, 85; Washington, 21).

26

Figure A-3.— Locations where fur seal stomachs collected In 1965 contained the following fishes
and squid (State and numberof occurrences In parentheses): Onychoteuthis banksU (California,
49); Clupea harengus pallasi (California. 4; Washington, 5); Thalelchthys paclflcus (Washing-
ton, 11).

Figure A-4. — Locations where fur seal stomachs collected In 1965 contained the following fishes
and squid (State and number of occurrences in parentheses): EngrauUs mordax (California, 39;
Washington, 20); and Gonatus fabrlcll (California, 17; Washington, 2).

28

WASHINGTON

ABRALIOPSIS SP.
■ GONATUS MAGISTER
A MOROTEUTHIS ROBUSTA
• ONCORHYNCHUS SPR

Figure A-5. — Locations where fur seal stomachs collected in 1965 contained the following fishes
and squid (State and number of occurrences in parentheses): Abrallopsis sp. (California, 7);
Gonatus maglster (California, 4); Moroteuthis robusta (California, 4); and Oncorhynchus spp.

(Washington, 8).

29

Figure A-6. — Locations where fur seal stomachs collected in 1965 contained the following fishes
and octopus (State and number of occurrences in parentheses): Cololabis salra (California,
14); Tremoctopus sp. (California, 1); Pleuronectidae (California, 2); and Gasterosteus aculeatus

(Washington, 7).

30

Figure A- 7. — Locations where fur seal stomachs collected In 1965 contained Merluccius
productus (70 occurrences off California and 1 off Washington).

31

Figure A-8. --Locations where fur seal stomachs collected In 1965 contained the following fishes
(State and number of occurrences In parentheses): Sebastodesspp. (California, 45; Washington,
1); and Anoplopoma fimbria (California, 3; Washington, 1).

32

APPENDIX B

OBSERVATION OF JAPANESE PELAGIC
FUR SEAL RESEARCH, 1965

By
Hiroshi Kajimura

Under Article II, paragraph 5, of the Interim
Convention on Conservation of North Pacific
Fur Seals, member countries agreed to ex-
change scientific personnel by mutual consent
of the parties concerned. The last U.S. ob-
server sent to Japan under this provision was
G. K. Tanonaka, who visited in April and May
1958.

In February 1963 the North Pacific Fur Seal
Commission agreed to conduct researchonthe
quality of sealskins by sex, age, and time and
method of collection. I went to Akahama
(Ozuchi), Japan, in 1965 to observe Japanese
pelagic fur sealing, particularly in regard to
selection of seals, methods of collecting to
reduce damage to skins, and skin- handling
techniques aboard vessels and on shore.

I arrived in Tokyo, Japan, 7 April and visited
the Tokai Fisheries Laboratory, where the
marine mammal specialists are headquartered,
before going by train to the field station at
Ozuchi on 10 April. During my stay at the
field station from 10 April to 10 May I spent
15 days aboard a vessel. Because of bad
weather, seals were hunted on only 6 days.

I would like to thank the biologists of the
Tokai Fisheries Laboratory, Tokyo, and the
members of the research vessels for making
my stay in Japan rewarding as well as enjoy-
able.

PERSONNEL

The four biologists of the Marine Mammal
Section, Tokai Fisheries Laboratory, Tokyo,
Japan, handle the various aspects of fur seal
research conducted by Japan. Each biologist
has a tour of duty at the field station at Aka-
hama during the sealing season (fig. B-1).

Temporary employees at the field station
were three biological aids and four office
clerks. One biological aid is assigned to each
vessel to collect data at sea and assist at the
field station when the vessels are in port. The
office clerks transfer field notes to final data
sheets and punchcards, and do miscellaneous
tasks.

FIELD STATION LABORATORY

The Akahama field station is the base for
Japanese pelagic fur seal research. Akahama,
in Iwate Prefecture, is a small fishing village
about 1.5 nniles from the town of Ozuchi
(Otsuchi) on the Pacific Ocean side of Honshu

Island (fig. B-2). Akahama-Ozuchi has been
one of the main ports used by Japanese pelagic
sealers since earliest sealing times and is
considered by the Japanese as the harpoon
vessel capital of the world.

VESSELS AND EQUIPMENT

Three vessels were chartered by the Japa-
nese Government in 1965 to conduct pelagic
fur seal research (table B-1). These char-
tered vessels, known as "tsukinnbo-sen" or
harpoon vessels, were described by Austin
and Wilke (1950). They are designed mainly
for collecting fur seals, porpoises, and sword-
fish, but are also used for miscellaneous
fishing. The only difference between the ves-
sels used now and those described by Austin
and Wilke is size; present vessels are larger
and have more modern equipment (35 gross
tons compared with 20 gross tons). Because
the vessels are not equipped with radar, navi-
gation is by compass, radio direction finder,
and the captain's knowledge of the locality.

Figure B-1. --Biologist, In front of field station laboratory
at Akahama.

Table B-1. --Harpoon vessels chartered for fur seal research by
Japan in 1965

Vessel name

Tonnage

Horse-
power

Max.

speed

Length

Beani

Draft

No. 3 Hachiman Maru
No. 5 Tenyu Maru
No. 5 Nikko Maru

29.95
35.71

160
120

no

Knots

8
8
8

Ft.

60.1
59.3
63. A

Ft.

13.7
13.3

13.8

Ft.

6.2
5.9
6.6

33

PA C I F I C
OCEAN

'IVIIYAGI
/ PREF.
ISHiNOMAKI

AKAHAMA -OZUCHI

^KAMAISHI
•C_KESENNUN

ONAGAWA

KINKASAN

Figure B-2. — Fishing villages visited by the Nlldco Maru, 10 April to 10 May 1965.

34

One of these vessels, No. 5 Nikko Maru
(fig. B-3), has been under charter since the
beginning of the present pelagic fur seal
research program, which is now in its eighth
consecutive year. The other two vessels are
in their fifth and sixth consecutive years of
pelagic research.

The normal vessel complement of 1 3 to 15
(fig. B-4) includes a captain who usually is the
chief hunter, an engineer, a radio operator,
2 to 4 hunters, 5 deck hands, and 3 boys
(1 a cook).

The extremely large crews of these vessels
are not needed for fur seal work, but after
they finish sealing they hunt for porpoise and
fish for saury and swordfish. Such work re-
quires a crew of 14 to 15 men. If the men are
not hired for a full year, they will seek em-
ployment elsewhere. It is difficult to hire a
crew for only half a season.

Figure B-3. — A harpoon vessel, the No. 5 Nikko Maru, of
the type chartered for fur seal research.

Figure B-4.--Crew members of the chartered fur seal
research vessel. No. 5 Nikko Maru.

RELATION OF WEATHER TO SEAL
MIGRATION OFF JAPAN

Owing to an unusually cold spring in 1965
and abnormal oceanographic conditions off the
coast of Japan, the fur seal migration off

northern Honshu and Hokkaido was delayed
about 3 to 4 weeks. Sealing off the coast of
Iwate Prefecture normally occurs during late
April and early May. By the middle of May
and in early June, migrating seals are usually
farther north, off Aomori Prefecture and Hok-
kaido, As late as 10 May 1965, however, nni-
grating seals were still in the warmer waters
off Miyagi Prefecture near Kinkasan, about 240
miles south of Hokkaido,

OBSERVATIONS OF JAPANESE
PELAGIC SEALING

Because of their relatively small size, the
harpoon vessels enter harbor each night (or
drift offshore when the sea is calm). The
hunting range is, therefore, limited to a dis-
tance of about 100 miles per day; hunting usu-
ally extends only 10 to 50 miles offshore. The
vessels leave port each morning between 0200
and 0400, depending on the area to be covered.

On reaching the hunting area, hunters and
lookouts take their places on the harpoon
(shooting) platforms and in the crow's-nest
to watch for seals. When a seal is sighted,
the vessel approaches it at full speed (fig,
B-5), Two hunters are stationed on the plat-
form with single- or double-barrel 12-gage
shotguns loaded with No. 00 buckshot. The
chief hunter (gunner) stands up forward at the
bow; the second hunter stands behind hinn, on
the side of the vessel that is nearest the seal.
Shooting seals from harpoon vessels is diffi-
cult, not only because of engine vibrations but
because the shooting platform has no protective
railing. The shin- high railing shown in figure

Figure B-5.--Hunters shooting fur seal from bow platform.
(Note shln-hlgh railing on bow platform.)

35

B-5 offers little protection if the hunters lose
their balance. Sealing is, therefore, lim-
ited to periods of favorable weather when the
hunters are able to stand on the platform to
shoot.

During the approach to a seal, a lookout
standing behind the gunners controls the direc-
tion of the vessel by arm signals to the helms-
man and the speed by signals to the engine-
room. The ship, which is normally steered
with the conventional ship's wheel from the
pilothouse, is manually steered during sealing
by two men with a tiller attached directly to
the rudder. Tiller steering is quicker, making
the vessel more maneuverable than when under
conventional steering (fig. B-6).

A 15- to 18-foot bamboo pole with a four-
pronged gaff on one end and a long line on the
other (fig. B-7) is used to recover dead fur
seals, A deckhand throws the retrieving pole
toward the seal, drags it over the seal until
the skin is hooked, and then pulls the animal
aboard. The seal is normally recovered while
the vessel runs at reduced speed. This method
of recovering seals is very efficient but re-
quires great skill, attained only after many
years of experience. Seven of the crew mem-
bers on the Nikko Maru have sailed on this
vessel for the past 14 years; vessel per-
sonnel has changed little during 8 consecu-
tive years of pelagic fur seal research. The
long experience of the crew working as a
unit has contributed much to the vessel's
nnarked success in sealing. The numbers of
seals seen and collected by the Nikko Maru,
from 10 April to 10 May 1965, are shown in
table B-2.

Figure B-7. — Deckhands ready to throw retrieving pole to
recover dead seal.

Table B-2, --Number of seals seen and collected
by the Nikko Maru, 10 April to 10 May 1965

Date

Total seals
seen

Total seals
collected

Apr. :

13

17

2

25

26

May:

1

2

Number

5
3

1
10
15

70
36

Number

0
3

0
7

10

30
24

Total

UO

74

Figure B-6. — The tiller, located on the stern, improves
the maneuverability of the vessel.

Field Data Collection Methods

Preliminary data taken for each fur seal
brought aboard the vessels were: time seal
was sighted and brought aboard vessel; number
of seals in a group; and behavior (swimming
or sleeping).

As soon as a seal is brought aboard the
vessel, the surface water temperature is
recorded (as read directly off a temperature
gage mounted in the pilothouse) and a num-
bered plastic tag is affixed on the front flipper
for identification.

Each animal is measured (from tip of snout
to tip of tail) on a calibrated measuring board

36

(fig. B-8), and weighed on a graduated beam
scale (fig. B-9). The metric system of meas-
urement is used.

The sex of each animal is recorded and, for
pregnant females, the weight, length, and sex
of the fetus are recorded. The genital tract of
each female is tagged and placed in 10 percent
formalin for examinations in the laboratory.

Both upper canine teeth are collected by
cutting off the snout with a meat cleaver (fig.
B-10). The snout is placed in a cloth bag with

Figure B-8.--Calibratecl board for measuring seals on
vessel.

Figure B-9. — Weighing fur seal wich a graduated beam
scale.

Figure B-10. — Cutting off snout to preserve upper canine
teeth for age determination.

an identifying tag. Subsequent work on the
snouts is done at the field station laboratory.

Stomachs are tagged, tied, cut off above the
cardiac sphincter and below the pyloric sphinc-
ter, and placed in barrels containing 1 0 percent
formalin. (Formalin is not injected into the
stomach to stop digestion, as is done aboard
U.S. research vessels.)

When fur seals are skinned aboard the ves-
sels, the animals are first slit open along the
ventral surface from the lower jaw to the anus
and a cut is made around each flipper. The
skins are then carefully removed with a knife.
The skins are washed and cooled by towing
them alongside the vessel for 15 to 20 minutes
while hunting is continued. They are soaked in
a concentrated brine solution overnight and
salted down in bins the following morning, for
a minimum of 2 weeks. The crew unloads the
skins on the dock whenever a shipment is
made; workers hired by the processing firm
fold and pack the salted skins in burlap bags
for shipment (figs. B-11 to B-13). The bundled
skins are shipped by truck to a Tokyo factory
where they are fleshed and processed.

In February 1965, the North Pacific Fur
Seal Commission approved a plan to standard-
ize preliminary processing of sealskins (skin-
ning, washing, fleshing, curing, packing, ship-
ping, and storage) to be used for research on
quality by each member nation. The summary
of instructions for preliminary processing of
sealskins was as follows:

1. Remove skins without cuts or flay marks.

2. Wash and soak in sea water 4 hours.

3. Scrape blubber from the skin within 2
hours after washing. If there is a delay of 24
hours or more between soaking and fleshing.

37

Figure B-11. — Sealskins being unloaded from vessel.

Figure B-12. — Salted skins being folded and placed in
burlap bags.

cover the skins with salt until the blubber can
be removed, or obtain a substitute sample if
the above conditions are not satisfied.

4. Cure skin in salt for two 7-day periods,
using fresh salt for each period. Lay skin flat,
fur side down, to cure. Make certain there are
no rolled edges that are not salted.

5. Rub with a mixture of 10 percent pow-
dered boric acid and 90 percent salt, roll
tightly, and pack in wooden barrels, or other
noncorrodible, watertight container.

6. Keep skins cool during shipping and
storage; refrigerate between 0° and 5° C, if
possible.

All deviations from the above instructions
on preliminary processing of sealskins were
to be recorded, along with the date and locality
of capture, sex, age, length, and weight of each
animal.

Figure B-13. — Bundles of sealskins being prepared for
shipment to processing plant.

Sealskins collected by Japan for researchon
skin quality deviated from the above methods
owing to conditions aboard the vessel and the
lack of storage facilities on land. These devia-
tions, although not actually observed, were as
follows:

Steps 1 and 2 to be followed as in the in-
structions.

Step 3. All skins to be salted, and the vessel
to return to port (Akahama-Ozuchi) each day
to flesh skins because of lack of space aboard
the vessel.

Step 4. Skins to be salted aboard the vessel
during the first 7-day period. Skins to be salted
in barrels (skins laid out flat) and shipped to
processing plant in Tokyo during the second
7-day period.

Steps 5 and 6 will be handled by the proc-
essing firm in Tokyo because refrigeration is
not available during shipping and storage.

Laboratory Examinations

In the laboratory stomachs, teeth, and geni-
tal tracts were examined.

Stomachs.- -Each fur seal stomach was pre-
served in 10 percent formalin aboard the ves-
sel. The stomachs are soaked overnight in
fresh water when examining stomachs at the
laboratory. The stomach is then cut open, and
the contents are identified and separated by
species whenever possible. The volume of each
species is measured by water displacement.

Teeth.- -Snouts containing both upper canine
teeth are cooked at the laboratory by one of the
biological aids. The teeth are pulled, cleaned,

38

identified, and placed in envelopes. The teeth are then counted, using natural transmitted

are ground lengthwise by holding the tooth light, to determine age.

against a mechanically turned grinding wheel.

When the desired thickness (center of tooth) is Genital tracts.- -The condition of female

reached, the work is finished manually on a genital tracts collected is noted at the labora-

grinding stone. The internal annuli of the tooth tory, rather than at the time of collection.

39

APPENDIX C

BEHAVIOR NOTES

The actions of seals when first seen were
recorded during the running of transects off
California in 1965. These actions were classi-
fied as: (1) active- - including swimming and
feeding, (2) sleeping, and (3) resting but awake.

If the sea was calm, most seals were sleep-
ing during the morning, but in the afternoon
most would be active or awake and only a few
asleep. During stormy weather nnost seals
were active.

Other observations are listed in table
C-1.

Table C-1. — Observations by the U.S.A. of unusual fur seal behavior in the eastern Pacific in 1965

Date of
observation

Seals

Tag number,
if animal
collected

Locality where
observed

Observation

Apr. :

2

Number

1
1
6

2

1

4

1
1

1
1

1
1
4

1
2

1

1

Washington

418

483
California

42

150
159
161

283

Off Cape Flattery

do

Off Westport

do

In kelp patch

9

On kelp

16

All in and around large

21

kelp patch
One growled

■:>■:>

do

In kelp patch

18

Off Farallon Is., transect

no. 4
Transect no. 5
Off Monterey, transect

no. 7
do

Near kelp patch

19

Sleeping next to log

21

On log

21

On kelp

23

Off New Year I.

do

In kelp

May:

8

Do.

13

End transect no. 2
Monterey Se aval ley

North of Pt. Sur

Off San Simeon

do

Lying on kelp

26

Possibly medium-size

27

bull with 3 females
Growled

29

Near kelp

29

In kelp

June:

Off Farallon Is.

On kelp

40

APPENDIX D

Table D-1. --Injured, siok, and diseased fur seals collected pelagically by the U.S.A. in the

eastern Pacific in 1965

Seal
number

Date
collected

Locality

Remarks

US65-425

11 Apr.

Off Cape Flattery, Wash.

Age 1, wt. 6 kg., guard hair absent from back,
generally poor condition, scar tissue on
stomach

US 65 -102

20 May

Off Farallon Is., Calif.

Small round scar (1-1/2" diam.) on back 6" above
tail; some scars behind lower nipples

US65-10'i
US65-169

20 May
31 May

do

Small rubbed spot or scar on back, 2" diam.
Tip of flipper sliced off (not checkmark)

Monterey Seavalley

US65-175

31 May
31 May
31 May

do

Small rubbed spot 1" diam. on belly

Two rubbed spots, lower belly

Half of belly matted with grease, two healed
scars on right hind flipper, one healed scar
rear left flipper.

US65-185

do

US65-186

do

US65-199

2 June

do

Large scar on back, photos taken

US65-255

19 June

Off Monterey

Very thin

41

APPENDIX E

FETAL MORTALITY DURING THE LAST
6 MONTHS OF GESTATION

by
Victor B. Scheffer and Ancel M. Johnson

This section deals with the question: "Can
fetal nnortality be estinnated from study of the
pregnancy rates of seals taken at sea?"

According to Niggol (1960), fetal mortality
between 11 January and 19 July is nearly
equal for the sexes. He tabulated sex ratios
by 10-day periods for 3,081 fetuses and found
that "no shift in mortality rate by either sex
was evident" (p. 428).

We have now studied pregnancy rates by
month and by age of the pregnant female,
between January and June, in 8 years be-
tween 1952 and 1964 (table E-1). The sample

includes 5,817 females, of which 4,321 (74.3
percent) were pregnant. ("Pregnant" means
that the female was carrying a live fetus; not
that she was recently post partum, an extended
meaning used by Abegglen and Roppel (1959).)
The study is based on three assumptions:
(1) that pregnancy rates are consistent from
year to year, (2) that pelagic sampling is
randonn, and (3) that a decrease in pregnancy
rate with time for each age class reflects the
loss of fetuses through absorption or abortion.

Findings.-- The regressionof pregnancy rate
on time for each of the age classes indicated
by the nine columns of table E-1 is highly
variable, and the slope is not significant.
We concluded that fetal mortality cannot be
estimated from these data because their vari-
ability is too great.

Table E-1. --Eight-year summary of pregnancy rates of seals collected pelagically by the U.S.A.

from California to Alaska'"'

Age in years

Month

^

5

6

7

8

9

10

10+

Total

Jan. 2

N

26

22

21

47

61

49

55

241

522

Np

1

8

19

39

47

43

51

197

405

i

3.9

36.4

90.5

83.0

77.1

87.8

92.7

81.7

77.6

Feb

N

61

86

100

122

122

108

111

545

1,255

Np

-i

44

82

98

111

101

99

441

980

i

6.6

51.2

82.0

80.3

91.0

93.5

89.2

80.9

78.1

Mar

N

61

56

65

70

66

55

66

546

985

Np

1

24

48

51

54

45

58

430

711

*

1.6

42.9

73.9

72.9

81.8

81.8

87.9

78.8

72.2

Apr

N

109

88

79

91

126

110

82

532

1,217

Np

2

32

49

72

1D2

101

66

436

860

i

1.8

36.4

62.0

79.1

81.0

91.8

80.5

82.0

70.7

May

N

43

48

59

64

93

69

90

507

973

Np

0

12

50

53

77

62

82

406

742

$

0

25.0

84.7

82.8

82.8

89.9

91.1

80.1

76.2

June

N

95

60

70

79

94

89

71

306

864

Np

3

27

52

64

81

81

60

255

623

lo

3.2

45.0

74.3

81.0

86.2

91.0

84.5

83.3

72.1

Total

N

395

360

394

473

562

480

475

2,677

5,816

Np

11

147

300

377

472

433

416

2,165

4,321

5t

2.8

40.8

76.1

79.9

84.0

90.2

87.6

80.9

74.3

■"" Samples taken in various months between January and June in years 1952, 1955, 1958-62, and
1964. N = number in sample; Np = number pregnant; percent = ^ of sample pregnant.

^ Includes two seals taken in December 1960.

MS. #1544

42

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