XFWC-A 302 1-18 (1969)
U.S. Fish Wildl. Serv. Circ.

FAO Fisheries Synopsis No. 40 BCF/S 40

Pacific mackerel -1,75(01), 002,03

SYNOPSIS OF THE BIOLOGICAL DATA ON THE
PACIFIC MACKEREL

Scomber japonicus Houttuyn
(Northeast Pacific)

UNITED STATES DEPARTMENT OF THE INTERIOR
FISH AND WILDLIFE SERVICE

BUREAU OF COMMERCIAL FISHERIES Circular 302

UNITED STATES DEPARTMENT OF THE INTERIOR
U.S. Fish and Wildlife Service

BUREAU OF commercial FISHERIES

Synopsis of the Biological Data on the

Pacific Mackerel, Scomber japonicus
Houttuyn (Northeast Pacific)

By

DAVID KRAMER

FAO Species Synopsis No. 40

Circular 30Z

Washington, D. C.
February 1969

CONTENTS

Page

Introduction 1

1 Identity 1

1.1 Nomenclature 1

1.2 Taxonomy 1

1.3 Morphology 2

2 Distribution 3

2.1 Total area 3

2.2 Differential distribution 5

2.3 Determinants of distribution changes 5

2.4 Hybridization 5

3 Bionomics and life history 5

3.1 Reproduction 5

3.2 Preadult phase 7

3.3 Adult phase 9

3.4 Nutrition and growth 9

3.5 Behavior 10

4 Population 11

4.1 Structure 1 :

4.2 Abundance and density (of population) i;

4.3 Natality and recruitment 1 ;

4.4 Mortality and morbidity 1 :

4.5 Dynamics of population (as a whole) i;

4.6 The population in the community and the ecosystem 1 ;

5 Fishery 13

5.1 Fishing equipment 13

5.2 Fishing areas 13

5.3 Fishing seasons 13

5.4 Fishing operations and results 13

6 Protection and management 13

6.1 Regulatory (legislative) measures 13

6.2 Control or alteration of physical features of the environment 17

6.3 Control or alteration of chemical features of the environment .... 17

6.4 Control or alteration of the biological features of the environment. . 17

6.5 Artificial stocking 17

Literature cited 17

Synopsis of the Biological Date on the
Pacific Mackerel, Scomber japonicus
Houttuyn (Northeast Pacific)

By

DAVID KRAlvlER, Fishery Biologist

Bureau of Commercial Fisheries

Fishery-Oceanography Center

La Jolla, California 92037

ABSTRACT

This synopsis attempts to bring together all knowledge extant on the identity
(nomenclature, taxonomy, morphology), distribution, bionomics, life history,
population, fishery, and protection and management of the Pacific mackerel.

INTRODUCTION

BCF (Bureau of Commercial Fisheries) has
assigned the preparation of synopses on var-
ious economically important species to a
number of its laboratories. Most of these
synopses will be published in the U.S. Fish
and Wildlife Service Circular series,' and
will follow the format presented in "Prepara-
tion of synopses on the biology of species of
living aquatic organisms," by H. Rosa Jr.,
Biology Branch, Department of Fisheries,
Food and Agriculture Organization of the
United Nations.

Pneumatophorus diego (Ayres) Jordan and
Hubbs (1925: 221). California.

1.2 Taxonomy

1,21 Affinities

Phylum Chordata

Class Teleostomi

Order Perciformes

Family Scombridae

1 IDENTITY

1. 1 Nonnenclature

1.11 Valid name
Scomber japonicus Houttuyn.

1.12 Synonomy

Scomber iaponicus Houttuyn (1782: 331).
Japan.

Pneumatophorus iaponicus (Houttuyn, 1782);
Starks (1921: 222-223).

Scomber diego Ayres (1856: 101). Santa
Barbara, Calif.

One synopsis, written by MacGregor, has appeared in
the U.S. Fish and Wildlife Service Special Scientific
Report — Fisheries series.

SCOMBER

Scomber Linnaeus

Scomber Artedi, in Linnaeus (1758: 297)
(S. scombrus Linnaeus).

Cordylus Gronow (1854: 163) (Scomber
scombrus L.).

Pneumatophorus Jordan and Gilbert ( 1883:
593) (as subgenus). Starks (1921: 222-
223),

Matsui (1967) separated the mackerels into
two genera. Scomber and Rastrelliger, and
cited differences in 14 characters, chief of
which were the presence in Scomber of vomer -
ine and palatine teeth (lacking in Rastrelliger)
and a well-developed anal fin spine (lacking in
adult Rastrelliger). Other differences included:
the hypohyal nearly as long as or longer than

epihyal in Scomber, but less than one -third as
long as the epihyal in Rastrelliger; 12 to 28
first dorsal fin interneurals in Scomber, 11
(rarely 10) in Rastrelliger; the first haemal
spine somewhat flattened and bent backward
in Scomiber but flattened with the middle hooked
and the distal part nearly vertically directed
in Rastrelliger.

Matsui recognized only three species of
mackerels with 31 vertebrae and 5 finlets in
the genus Scomiber (including Pneumato-
phorus). These include S^. scombrus Linnaeus,
S. japonicus Houttuyn, and S. australasicus
Cuvier. S. scombrus differs from the others
in having nnore heavily ossified bones, in hav-
ing no swim bladder, and in having the first
haemal spine anterior to the first interhaemal
bone. He saw no reason for recognizing
Pneumatophorus for the other two species. He
summarized 12 characters for comparison of
the three species, the most distinguishing of
which, other than the absence of a swim blad-
der in scombrus, is the number and arrange-
ment of the interneurals under the first dorsal
fin--21 to 28 in S. scombrus, 15 to 21 in S.
australasicus, and 1 2 to 15 in S. japonicus. He
showed these arrangements by a representa-
tive diagram in his figure 7.

used are blue mackerel, greenback mackerel,
striped mackerel, and Americanmackerel.

1.3 Morphology

1.31 External morphology

Dorsal IX-I, 9 to 13-IV to VI; anal I-I, 9 to
11 -IV to VI; pectoral 17 to 19; caudal 17;
pelvic I, 5; first dorsal fin rather high, re-
ceived entirely into a groove when depressed,
widely separated from the much lower second
dorsal; scales small, easily lost; two very
small keels on each side of the caudal peduncle.
Color: dark green to blue above with metallic
reflections shading into iridescent silvery on
the sides and below; a series of about 30 wavy,
dark streaks run vertically down the back to
just below the lateral line (fig. 1).

Matsui (1967) differentiated three popula-
tions of S. japonicus in the temperate zones of
the Pacific Ocean and the west and east Atlantic
Ocean (table 1).

The Pacific mackerel off the coast of North
America are not known to mix with any of the
other populations designated above. Racial
differences were investigated in this group by
Fry and Roedel (1949) in tagging experiments --

Figure 1. — Scomber japonicus (= Pneumatophorus dlego) Houttuyn (adapted from frontispiece. Fitch, 1951).

1.22 Taxonomic status
See above.

1.23 Subspecies
See above.

1.24 Standard common names

The name officially sanctioned by the State
of California for purposes of keeping records
is Pacific mackerel. Other names variously

see 3.51 below--and by Roedel (1952) in a
racial study.

For the racial study, Roedel examined speci-
mens from six geographic regions: British
Columbia, southern California, northern Baja
California (Soledad Bay), central Baja Cali-
fornia (Sebastian Vizcaino Bay), the Cape San
Lucas region including sections of the Pacific
and Gulf coasts of the peninsula, and the Gulf
of California.

Table 1. --Difference Betv/een populations of S. Japonic us (table 7 of Matsui, 1967)

Pacific

W Atlantic

E Atlantic

Pigment pattern on
belly

Usually unmarked or
only lightly marked

Usually clearly marked
by a number of fairly
large spots; some-
times by broken wavy

Usually clearly marked
by broken, wavy lines;
sometimes by thicker
lines that almost

lines; occasionally
unmarked

resemble spotting;
occasionally unmarked

Mandibular and

premaxillary teeth

Lightly crenulated

Strongly crenulated

Strongly crenulated

Scales

Smaller than those
of Atlantic

Larger than those of
Pacific population

Similar to W Atlantic

Gill rakers on
lower 1st arch
(on individuals 80
mm. SL or greater)

25-29

25-29

29-35

Distribution

China, Korea, Japan-
Boninls.; Coast of
Calif., Baja Calif.,
Gulf of Calif. -Chile

Massachusetts-
Venezuela; Argentina

Mediterranean;
Azores-Gulf of Guinea;
Capetown

Four physical characteristics were selected
for detailed study. Three were related to the
initial position of vertebral structures: the
haemal arch, the haemal brace either single
or paired, and the paired haemal brace; and
the fourth to the head length relative to fork
length.

Statistical analyses gave evidence of five
populations, each region, with the exception of
British Columbia and California, being sepa-
rable in some degree from adjoining regions.
Tag returns, however, demonstrated that a
portion of Vizcaino fish eventually reached
California waters. The Cape San Lucas ma-
terial differed radically in all respects from
the northern regions and was separable from
Gulf of California fish except in regard to the
initial position of the haemal arch.

1.32 Cytomorphology
No data available.

1.33 Protein specificity
No data available.

2 DISTRIBUTION

2. 1 Total area

The Pacific mackerel in the northeast Pacific
Ocean has ranged from southeast Alaska
(Rounsefell and Dahlgren, 1934) to Banderas
Bay, Mexico (Fitch').

The natural regions ' of the oceans inhabited
by this mackerel thus included northwest
American coastal waters (4.2.4), SanFrancisco
waters (4.5.2), California waters (4.6.3), and
west Mexican waters (4.6.4). Now, as deter-
mined from populations of larvae, its range
may extend only as far north as Point Concep-
tion, Calif.,* south along the coast and into all
of the Gulf of California (Kramer, 1960), The
offshore extent of the population is as far as
200 nautical miles (370 km.) off northern
Baja California, and about 200 nautical miles
(370 km.) off central Baja California, with the
greatest numbers of larvae concentrated off
upper and central Baja California (fig. 2),
Data from two cruises in 1956 into the Gulf
of California by the CalCOFI (California
Cooperative Oceanic Fisheries Investigations)
in February (Ahlstrom, 1956) and April (un-
published) showed that the populations of
larvae in either of these months exceeded by
far the total population of larvae in 1956 in
the entire CalCOFI area for the whole year of
surveys on the outer coast. Furthermore,
although the CalCOFI data for the outer coast
showed that Pacific mackerel larvae extend
only as far south as Cape San Lucas, the data

John E. Fitch, California Department of Fish and
Game, Terminal Island, Calif., by correspondence.

For definition of these regions, see Rosa, H. Jr.,
Preparation of synopses on the biology of species of living
aquatic organisms. Biology Branch, FAO Fisheries Divi-
sion.

■• Recent reports of repeated traces of Pacific mackerel
with jack mackerel taken off Pt. Sur, Calif. — by corre-
spondence, Richard Parrish, California Department of Fish
and Game, Hopkins Marine Station, Pacific Grove, Calif.

130° 125° 120' 115' 110

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STATIONS OCCUPIED o

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1 1 1 1 1

Figure 2.— Distribution and relative abundance of Pacific mackerel larvae in 1955 (fig. 20 of Kramer, 1960).

for the Gulf cruise in February 1956 showed
very heavy concentrations of larvae off the
mainland of Mexico not delimited by the
southernmost extent of that cruise. The Gulf
population, then (see 1.31 above) may extend
as far as the limit of Banderas Bay defined by
Fitch (see footnote 1), or farther.

2.2 Differential distribution

2.21 Spawn, larvae, and juveniles.
See 2.1 above.

2.22 Adults

The adults occur in the same areas shown
for the distributions of their larvae (also see
2.1), and farther north, at least to Pt. Sur,
Calif, (see footnote 4).

2.3 Determinants of distribution changes
No data.

2.4 Hybridization

No evidence of hybridization.

3 BIONOMICS AND LIFE HISTORY
3. 1 Reproduction

3.11 Sexuality

The Pacific mackerel is heterosexual with
no evidence of sexual dimorphism.

3.12 Maturity

Fry (1936>b) stated that mackerels, ". . .
under 11-1/2 inches total length at the begin-
ning of the spawning season will not spawn that
season; some of the 12- and 1 2- 1/2-inch fish
and over three -fourths of the 13 -inch fish will
spawn. In terms of age--the yearling fish do
not spawn whereas most of the Z-year-olds
do." He stated further that these facts are
true for mackerels in California waters but
that some mackerels from the southern part of
Baja California seem to mature at a smaller
size.

3.13 Mating

Not observed but believed to be promiscu-
ous.

3.14 Fertilization
External.

3.15 Gonads

Few data are available on the fecundity of
the Pacific mackerel. MacGregor ( 1966) stated
that this mackerel produces 304 eggs per gram
of fish (based on counts for six specimens).
One of these was collected off Avalon, Catalina
Island, Calif, and another from San Hipolito
Bay, Baja California. The remaining four were
taken from a holding tank at the Scripps In-
stitution of Oceanography, La JoUa, Calif. For
want of better data, he included data from these

four in his totals, although he was not sure of
their validity. His data showed 309 and 220
eggs per gram of fish for the Avalon and San
Hipolito specimens, respectively, and 141 to
457 eggs per gram of fish for the other four
specimens.

3.16 Spawning

Studies of spawning of Pacific mackerel have
been made off southern California and Baja
California. Fry (1936b) stated that in 1936
Pacific mackerel spawned off southern Cali-
fornia from late April or early May to August --
the peak spawning was from May to early July.
Kramer (1960), using larvae as indicators of
spawning times, stated that spawning occurred
in the same months from 1952 through 1956 on
the surveys of the CalCOFI. He stated further
that there was some variation in peak spawning
times in different regions --April through July
off southern California and northern Baja
California and March through August off central
Baja California. Ahlstrom (1959a, text table
10) showed that the peak of spawning in 1957
off central Baja California occurred from June
through October and that the numbers of
larvae off northern Baja California indicated a
possible peak in April and May. Ahlstrom
(nnanuscript^ ) showed that numbers of larvae
in 1958 indicated peak spawning in March
through July off southern California and
northern Baja California and about August and
September off central Baja California. He
showed that in 1959 abundance of larvae was
very low but that a spawning peak was indi-
cated off southern California and northern Baja
California in June and July and off central
Baja California from June through September.

3.17 Spawn

The Pacific mackerel egg is pelagic and
spherical. The egg and the embryonic develop-
ment were described from live material by
Fry (1936a) and Orton (1953). Kramer (1960)
described the egg and embryonic development
in greater detail from preserved material,
from very early stages to hatching (figs. 3 and
4, table 2). Because of the various similarities
of Pacific mackerel eggs to those of the jack
mackerel, Trachurus symmetricus and the
Pacific hake, Merluccius productus, with which
they might be collected, Kramer compared the
three as shown in table 2. The sizes of Pacific
mackerel eggs shown in this table are averages
and may vary according to time as noted by Fry
(1936a) who concluded that eggs found at the
beginning of the spawning season were larger
than those found at the end of the season.

^Ahlstrom, Elbert H., BCF Fishery-Oceanography Cen-
ter, La JoUa, Calif. Sardine eggs and larvae and other
fish larvae off the Pacific coast, 1958-60.

Figure 3. — Development of the egg of the Pacific mackerel, Scomber japonlcus (= Pneumatophorus diego): a,
h, and c^, early embryonic development, c being the early stage immediately before blastopore closure; d,
middle-stage, just after blastopore closure; e, middle-stage, dorsal view of head and pectoral region, tail
separated from yolk-sac; f, late-stage, tail reaching to head; g, same as f, viewed from opposite pole
(adapted from drawing of Mattson, fig. 1 of Kramer, 1960).

Figure 4. — Late-stage egg and yolk-sac larvae of the Pacific mackerel. Scomber japonlcus (= Pneu-
matophorus diego): a, egg immediately before hatching; b, yolk-sac larva, 3.3 mm. long, just
after hatching; c, yolk sac larva, 3.5 mm. long, with yolk about two-thirds absorbed (adapted
from drawing by Mattson, fig. 2 of Kramer, I960).

Table 2.-

-Characters used to distinguish eggs and newly hatched larvae of the Pacific mackerel,
jack mackerel, and hake (table 2 of Kramer, 1960)

Item

Pacific mackerel

Jack mackerel ■■•

Hake^

EGG

Size

1.06 to 1.1^ mm.

0.96 to 1.02 mm.

1.07 to 1.18 mm.

Oil globule

0.26 to 0.27 mm. Off

Single--0.25 mm. On

Single--0.30 mm. Off

center from polar axis.

center on polar axis.

center from polar axis.

Yolk

Clear--magnifioation
shows tiny vacuoles
throughout yolk mass.^

Segmented .

Clear.

Perivitelline space

Narrower than either

Moderate (0.09 mm.

Moderate (0.06 mm.

hake or jack mackerel--

wide) .

wide).

about 0.02 mm. wide.-'

Pigmentation:

Yolk

On yolk near pectoral
region.

None .

On yolk near head.

Bnbryo

Dorsal pigment first one

Dorsal pigment extends

Dorsal pigmentation

line head to tail;

most of length of em-

continuous in middle-

splits laterally to two

bryo; ventral pigment

stage eggs; separates

dorsal lines when tail

occurs behind anus;

into patches in later-

grows away from yolk;

pigment seldom occurs

stage eggs.

before hatching head

forward of the eyes .

becomes fairly heavily

pigmented and body pig-

ment begins ventral

migration.

Number of myomeres

31

2-^

51 to 54.

YOLK-SAC LARVAE

Size

3.0 to 3.5 mm.

2.07 mm.

2.4 mm.

Pigmentation

Some dorsal pigment;

Dorsal and ventral

Collects in patches.

most pigment migrating

retained.

ventrally.

Oil globule

In rear of yolk-sac.

Under head in forward
portion of yolk-sac.

In rear of yolk-sac .

^Ahlstrom and Counts (1955)

The same noted in hake eggs.

'Fry (1936a).

In studies of vertical distributions Ahlstrom
(1959b, table 8) showed, on the basis of col-
lections at one station, that Pacific mackerel
eggs may be distributed from the surface to as
deep as 176 mi. Most eggs in that series were
taken between the surface and about 23 m.
deep; abundance fell off sharply below that
level.

3.2 Preadult phase

3.21 Embryonic phase. See 3.17
above.

3.22 Larvae phase.

Data on yolk-sac larvae are included in the
same table as those on the embryonic phase
(see 3.17 above) because the hatching stage
closely resembles the latest embryonic stage.
Kramer (1960) described the larvae (figs.
4, 5 and 6) in series from yolk-sac stage

through 16.5 mm. and added further data on
other specimens 18.9, 26.4, 30.0, and 66.6 mm.
long. Detailed descriptions were given on
changes in pigmentation, changes in body
form, and sequences of ossification of various
bony systems. Subsequent to the yolk-sac stage
pigmentation increases in large, circular spots
on top of the head, in two elongated patches on
the dorsal surface of the body, in a vertical
line on the base of the tail, in a line on the
posterior part of the lateral line, in ventral
area from the anus to the tail, and in two or
three spots on the ventral surface of the gut.
This pigmentation disappears in late -stage
larvae.

Size on size regressions of body parts on
standard length were expressed as straight
line relations (fitted by least squares). Rates
of increase are constant in relation to stand-
ard length for the head length, distance from
snout to anus, and distances fronn snout to first

Figure 5.— Development of the larva of the Pacific mackerel. Scomber japonicus ( = Pneumatophorus diego):
a, larva 4.0 mm. long; b, larva 5.0 mm. long; c, larva 7.8 mm. long; d, larva 10.5 mm. long (adapted from
drawing by Mattson, fig. 3 of Kramer, 1960).

Figure 6. — Late larva of the Pacific maclcerei, acomoer japonicus (= Pneumatophorus diego). 16.5
mm. long (adapted from drawing by Mattson, fig. 4 of Kramer, 1960).

dorsal and second dorsal fins. The body depth
in early-stage larvae increases at a rate twice
that of later stage larvae.

In Pacific mackerel, the order of first ap-
pearance of the fins is as follows: larval
pectorals (without rays), caudal, pectorals
(with rays), anal and second dorsal fins
simultaneously, anal and dorsal finlets simul-
taneously, first dorsal, and ventrals. The de-
velopment and appearance of the caudal keels
were discussed in detail because of the oc-
casional mis concept ion that they are pseudofins
with rays; each keel is made up of a series of
scales assembled linearly on a complex curve.

Kramer (1960) further described the ossifica-
tion and formation of the vertebral column and
its parts for centra, urostyle, hypurals and
epurals, vertebral arches and spines, ribs,
epipleurals, zygapophyses, and parapophyses.
Development of the fin and finlet interspinal
systems were described with particular em-
phasis on the individual parts of the interspinal
bones; especially the continuity of the inter-
neural system between the first and second
dorsal fins and the complex structures forming
the dorsal slot of the first dorsal fin.

For Pacific mackerel larvae collected from
1953-57, the change in abundance from 3.00 to

4.00 mm. long was 39.5 percent, 17.8 percent
at 5.00 mm., 6.7 percent at 6.75 mm., and Z.9
percent at 7.75 mm. The rapid decrease in
abundance after 7.5 mm. is assumed to be
masked by the ability of the larvae to escape
capture by swimming away from the mouth of
the collecting net.

3.23 Adolescent phase

In 1966 several hundred Pacific mackerel
were hatched from eggs and reared to preadult
stages at the Fishery-Oceanography Center.
At about age 2 months several in this batch
were accidentally killed in their tank. Eight of
these were X-rayed and measured; their
lengths ranged from 35 to 77 mm.

Nothing is known about juvenile Pacific
mackerel in the sea. Their behavior in aquar-
ium tanks indicates that they are particulate
feeders on live or "dead" animal food- -even
prepared food--taking live or frozen brine
shrimp, cut bait, fish or squid, and prepared
trout food. The last was the least digestible;
undigested material was voided shortly after
feeding.

3.3 Adult phase

3.31 Longevity

Most of the fish taken commercially are less
than 6 years old; most are 0, 1, 2 and 3 years
old. Occasionally large mackerel appear in the
catch. Fitch (1952) reported that the oldest
Pacific mackerel aged was 11 years. Fitch
(1956) reported that fish over 8 years old were
rare and that 6-year-olds were becoming very
uncommon.

3.32 Hardiness

No data on hardiness in ocean environment.
Mackerel held in aquaria do best in circular
plastic -lined tanks.

3.33 Competitors

No data except that since they are often
caught with jack mackerel, they may connpete
with that species.

3.34 Predators

Not studied except for predation by man.

3.35 Parasites, diseases, injuries
and abnormalities

No data for fish in ocean environment. In
captivity these fish eventually develop hyper-
plasia (cancer-like growths) on the skin in the
head region.

3.4 Nutrition and growth

3.41 Feeding

Pacific mackerel feed at any time of day.
They can be caught at night by chumming
under lights. They are particulate feeders.

3.42 Food

Fry (1936b) stated that this mackerel has a
tremendous appetite and shows very little dis -
c rimination inits feeding. Any animal matter
alive or dead is acceptable for food. He re-
ported that the fish takes fish or squid several
inches long, as well as small animals such as
cope pods or other free -swimming crustaceans.
He stated that in general they feed on one kind
of food at a time--for example, copepods,
anchovies, or squid, but not mixtures ofthese,
(See 3.23 for feeding in aquaria.)

3.43 Growth rate

When 2 years old. Pacific mackerel are about
12 inches (305 mm.) long and weigh about 3/4
pound (340)--Fitch, 1951. The relation of
weight, length, and age are shown in figure 7.

Fry (1936b) listed the following approximate
weights and lengths (in ounces and inches)
and called them "rough averages":

Weight

Length

Ounces

Gr.

Inches

mm.

1

28

6.50

165

2

57

7.75

197

4

113

9.50

241

8

227

11.75

298

16

453

14.50

368

24

680

16.25

413

32

907

17.75

451

40

1134

18.75

476

Condition factors (table 3) were derived from
data for 137 mackerel presented by Fitch
(1951, table 14) and from the data of G. O.
Schumann (unpublished) on 139 of 340 macke-
rel hatched and reared at this laboratory,

A- ^ n, <• 1 i^- weight X 10?
according to the formula: K fork length '

where weight is in grams and length is in
nnillimeter s.

Hatanaka and Takahashi (1956) captured and
held in captivity, for feeding experiments, a
number of Japanese mackerel for which I
calculated the condition factors. The factors
for their specimens, when caught, were higher
than the ocean specimens of comparable sizes
shown in table 3.

3.44 Metabolism

No data.

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26

m

1.50

24

1.25 20

IE

nr

1.00 16

0.75 12 —

■ 0.50 8

025 4 —

10 20 30l 40 50 60l 70 80 901

3 6 9

0

0 ^ol 130 140 I50l I60-»LENGTH V4 CMS.
12 15 -•^ LENGTH INCHES

I n n nz iinsni-*^ — age group

Figure 7. — Weight-length-age relation for Pacific mackerel (fig. 15 of Fitch, 1951).

3.5 Behavior

3.51 Migrations and local movements

The California Division of Fish and Game
(Fry and Roedel, 1949) devised a tagging pro-
gram in 1935, intensified it in 1940-41, and
concluded it in 1943. Mackerel were tagged at
several localities in central and southern
California and as far south as Magdelena Bay,
Baja California.

The Fisheries Research Board of Canada
also tagged a few fish off the Oregon coast
near the Columbia River.

Tag returns showed that the fish migrated
throughout the region covered by the tagging
program. One of the fish tagged off Oregon

was caught again off southern California, Fish
tagged off central California were recovered
in large numbers at Los Angeles and Newport
Beach canneries, and one was caught at San
Diego and another at Ensenada, Baja Cali-
fornia. Mackerel tagged off southern California
were recaptured at Monterey and San Fran-
cisco. Fish tagged at northern and central
Baja California were recovered at San Diego,
Newport Beach, Los Angeles, Monterey and
San Francisco, Calif. No fish tagged south of
San Roque Bay, Baja California, were re-
covered.

3.52 Schooling

The Pacific mackerel schools by size. It is
found in pure schools and mixed schools with
jack mackerel and Pacific sardine.

10

Table 3. — Condition factors of ocean and laboratory-reared specimens of Pacific mackerel

Ocean specimens-'-

Laboratory reared specimens^

Numcer

of

fish

Body

length

range

Condition factor

number

of

fish

Body
length
range

Condition factor

Mean

Ranj-e

Meaii

Range

7
10
10
10

10
10
10
10
10
10
10
10
10
10

mm.

85-100
101-125
126-150
151-175
176-200
201-225
226-250
251-275
276-300
301-325
326-350
351-375
376-400
401-425

82.5
89.0

96.1
100.3
100.0
103.6
104.3
107.3
115.5
120.8
124.3
122.9
126.0
125.0

81.6- 83.5

84.7- 92.5

92.8- 99.5
98.9-101.1
98.6-101.4

101.6-105.1
103.7-105.2
104.3-111.6
112.9-117.9
118.4-123.1
123.5-125.0
121.9-124.3
123.9-127.5
122.2-126.4

1
10
50
60

8

rnir,.

149
164-175
177-200
201-222
226-245

108.9
113.2
125.3
127.8
133.5

108.9

94.9-153.8

112.9-148.8

110.6-148.8

123.3-144.9

^From Fitch (l95l).

^Reared at BCF Fishery-Oceanographj- Center, La Jolla, Calif.
December 28, 1966.

Hatched June 20, 1966, died

3.53 Response to stimuli

Pacific mackerel are attracted to nightlights,
either as a response to the lights or to the food
attracted by the lights.

4 POPULATION

4.1 Structure

4, 1 1 Sex ratio

Unpublished data from the California De-
partment of Fish and Game assumes a 50-50
ratio of male to female (see footnote 4).

4.12 Age composition

See 3.31.

One-year-old fish do not spawn, but most
2-year-olds and all older fish do (see 3.12).

4.13 Size composition

The length composition of the catch for each
age group for the seasons 1939-40 through
1963-64 was as follows:

Range of length (mm.) by age group

0 I n III IV

168-332 218-385 235-392 278-405 282-400

V VI VII VIII IX

315-410 332-422 330-430 362-425 385-415

Fish at 7 years (6-f) were collected in the
1964-65 to 1966-67 seasons.

4.2 Abundance and density (of population)

No data available.

4.3 Natality and recruitment
No data available.

4.4 Mortality and morbidity

From analysis of tagging results, Fitch
(1952) calculated that the mortality rate for
the Pacific mackerel was between 74 and 78
percent per year for the seasons 1940-41
through 1942-43 (Fitch, 1952). He stated fur-
ther that in age studies mortality rates for
fish 2 years of age and older were calculated
for two 5-year periods, 1938-42 and 1943-47.
For the first, the rate was calculated at 48
percent between ages 2 and 3, 62 percent
between 3 and 4, and 70 percent between 4 and
5. For the second period the rate increased to
55, 77, and 80 percent per year for 2-, 3-,
and 4-year-old fish.

4.5 Dynamiics of population (as a whole)
No data available.

4.6 The population in the community and
the ecosystem

No data available.

II

Figure 8A. — Catch locations for Pacific mackerel for the season 1961-62
(fig. 1 of Messersmith and Hyatt, 1965).

12

FISHERY

5.3 Fishing seasons

5.1 Fishing equipment

5.11 Gears

Pacific mackerel are caught commercially
chiefly by roundhaul gear (purse seines and
lampara nets); catch by other gear is mostly
by scoop, a large commercial dip net (Mes-
sersmith and Hyatt, 1965),

Changes in types of gear and boats were
described by Croker (1933, 1938) in his ac-
counts of the mackerel fishery and by Scofield
(1951) in his descriptions of the types and
designs of purse seines and other roundhaul
nets.

Every type of gear has been used in this
fishery--set lines, handlines, pole lines, gill
nets, trammel nets, lampara nets, ring nets,
purse seines, and scoop nets --depending on
demand, availability, and man's efficiency.
The fish are located by such means as sight-
ings of schools fromi boats and airplanes and
use of electronic sounding gears.

5.12 Boats

As with gear, the fishery has increased its
efficiency by changing the types and sizes of
its boats, which range from skiffs, dories, and
small power boats, 30 to 50 feet (9 - 15 m.)
long to round haul boats, 50 to 85 feet (15 -26
m.) long that use ring nets and purse seines.
The small boats may use different gear at
different seasons, depending on the behavior of
the fish and sizes of schools.

5.2 Fishing areas

5.21 General geographic distribution

The Pacific mackerel fishery does not ex-
tend over the fish's entire range (see 2.1). The
fishery is limited largely to the area off
southern California (4.6.3) but some fishing
extends as far north as Monterey (4.5.2) --fig,
8. Some mackerel, usually small amounts, are
caught off Baja California (4.6.3) by the Cali-
fornia fleets (see 5.43 for catch). Mexican
landings are shown in table 4.

5.22 Geographic ranges
See 5.21.

5.23 Depth ranges
No data available.

5.24 Conditions of the grounds
No data available.

No regulation governs the seasonfor Pacific
mackerel. The State of California has estab-
lished a statistical season. May to April,
because the species is taken chiefly during the
fall and winter,

5.4 Fishing operations and results

5.41 Effort and intensity
No data available.

5.42 Selectivity

This is determined primarily by the fisher-
men according to their identification of species,
school size, and size of fish. Often there is no
selectivity because of the occurrence of this
species in mixed schools with jack mackerel
and pacific sardine.

5.43 Catches

Table 4 and figure 9 show the Pacific
mackerel landings for the years 1926-66.
Table 4 includes data on mixed landings as
recorded for jack mackerel and Pacific mack-
erel for 1916-25.

6 PROTECTION AND MANAGEMENT

6. 1 Regulatory (legislative) measures

6.11 Limitation or reduction of total
catch.

There are no limitations on catch of Pacific
mackerel.

6.12 Protection of portions of popu-
lation.

Protections of certain portions, particularly
small fish, have been suggested by the Cali-
fornia Department of Fish and Game in order
to prevent the exploitation of the young stocks.

Parrish and Blunt (manuscript ), in re-
porting on management efforts, stated that,
". . . evidence showing diminishing numbers
of older, mature fish in the catch and a de-
pendence upon individual strong year-classes
lead to enactment of an 11 inch minimum size
limit with 25 percent allowance by number for
undersized fish effective December 1, 1947.
The size limit was lowered to 8 inches from
August 1, 1948 to July 31, 1949. Other than
closures to purse seining around Santa Cata-
lina Island, within 3 miles of the Orange County
coast, and in Santa Monica Bay, no other re-
strictions have been enacted which n-iight limit

'Richard H. Parrish and C. E. Blunt, California De-
partment of Fish and Game, Terminal Island, Calif.
"The Pacific mackerel fishery: a summary of biological
knowledge and the current status of the resource."

13

SAN fBANC'SCO

PACIFIC MACKEREL
1962-1963 SEASON

Til ACE
B 1-20 IONS

ra 21 - JOO IONS
ED 201 - 2.000 TONS
■I OVEII 2,000 TONS

NORTMf aK

-OCE ANSiDt

Figure 8B.— Catch locations for Pacific mackerel for the season 1962-63
(fig. 2 of Messersmith and Hyatt, 1965).

14

SAN FRANC'SCO

SANTA C»UZ

PACIFIC MACKEREL
1963-1964 SEASON

T IIACE

^ 1-20 IONS

B3 Jl 200 IONS

CB 301 - 2.000 'ONS

ifCiBiS e^ANCaS

fPT BjChOS

Figure 8C. — Catch locations for Pacific mackerel for the season 1963-64
(fig. 3 of Messersmith and Hyatt, 1965).

15

Table 4-. — Pacific mackerel landings in California^ (see fig. 9) and Baja California,

Mexico, 1926-66

California landings from

Baja California landings^

Year

California

Water south

Total

Pacific

Pacific and

waters

of state

mackerel

jack mackerel^

Tons

Tons

Tons

Tons

Tons

1926

1,805

7

1,812

1927

2,364

6

2,370

—

—

1928

17,626

5

17,631

—

1929

28,987

1

28,988

—

1930

8,266

~

8,266

~

~

1931

7,127

7,127

1932

6,237

—

6,237

—

—

1933

34,807

—

34,807

—

1934

56,791

133

56,924

—

—

1935

72,633

581

73,214

~

~

1936

49,414

857

50,271

1937

30,416

52

30,468

1938

39,923

1

39,924

—

1939

40,455

(^)

40,455

1940

60,252

—

60,252

~

—

1941

39,084

39,084

1942

26,266

11

26,277

—

—

1943

37,625

7

37,607

—

1944

41,828

{')

41,828

—

1945

26,858

26,858

~

~

1946

26,938

26,938

1,081

1947

23,239

—

23,239

—

2,661

1948

19,693

—

19,693

—

470

1949

24,886

—

24,836

—

2,366

1950

16,325

~

16,325

~

3,602

1951

16,759

__

16,759

2,491

1952

10,302

—

10,302

1,911

1953

3,751

—

3,751

—

1,703

1954

12,516

180

12,696

4,984

—

1955

11,655

(^)

11,655

10,499

~

1956

25,006

25,006

13,025

-.—

1957

31,002

—

31,022

—

16,271

1958

13,817

7

13,824

—

1,154

1959

18,801

—

18,801

—

512

1960

18,404

{')

18,404

~

2,531

1961

22,055

22,055

6,141

1962

24,289

(.')

24,289

3,424

—

1963

20,121

(^)

20,121

11,443

—

1964

13,414

{')

13,414

9,608

—

1965

3,525

{')

3,525

9,356

—

1966

—

—

2,258

1

5,416

~

■"■Landings of Pacific and jack mackerel were not recorded separately in 1916-25. Combined land-
ings (tons) were: 1916, 557; 1917, 1673; 1918, 2003; 1919, 1327; 1920, 1499; 1921, 1457; 1922,
1233; 1923, 1777; 1924, 16U; and 1925, 1753.

^No data previous to 1946.

^No attempt made to separate species. When statistics indicated composition of a capture
(two or more species) equal percentage representation was given each species.

"^Less than one ton.

16

the Pacific mackerel catch. . , ." Theyfurther
reported a recommendation by the California
Department of Fish and Game for a bag limit
on Pacific mackerel which was not imple-
mented.

6.2 Control or alteration of physical fea-
tures of the environment

6.3 Control or alteration of chemical
features of the environment

None.

6.4 Control or alteration of biological
features of the environment

None.

None.

6.5 Artificial stocking.

None.

1930

1935

1940 1945 1950

YEAR

1955

I960

1965

Figure 9. — Landings of Pacific mackerel in California, 1926-66 (See Table 4).

LITERATURE CITED

AHLSTROM, ELBERT H.

1956. Eggs and larvae of anchovy, jack

mackerel, and Pacific mackerel. Calif.

Coop. Oceanic Fish. Invest. Progr.

Rep., 1955-1956: 33-42.
1959a. Sardine eggs and larvae and other

fish larvae Pacific coast, 1957. U.S.

Fish Wildl. Serv., Spec. Sci. Rep. Fish.

328, vi + 99 pp.
1959b. Vertical distribution of pelagic fish

eggs and larvae off California and Baja

California. U.S. Fish Wildl. Serv.,

Fish. Bull, 60: 107-146.
AHLSTROM, ELBERT H., and ROBERT C.
COUNTS.
1955. Eggs and larvae of the Pacific hake

Merluccius productus. U.S. Fish Wildl.

Serv., Fish. Bull. 56: 209-245.
AYRES, W. O.

1856. Description of a new species of

mackerel. Proc. Calif. Acad. Sci. 1:101.
CROKER, RICHARD S.

1933. The California mackerel fishery.

Calif. Div. Fish Game, Fish Bull. 40,

149 pp.

1938. Historical account of the Los Angeles
miackerel fishery. Calif. Div. Fish
Game, Fish Bull. 52, 62 pp.
FITCH, JOHN E.

1951. Age composition of the southern Cali-
fornia catch of Pacific mackerel 1939-
40 through 1950-51. Calif. Dep. Fish
Game, Fish Bull. 83, 69 pp.

1952. The decline of the Pacific mackerel
fishery. Calif. Fish Game 38: 381-389.

1956. Pacific mackerel. Calif. Coop.

Oceanic Fish. Invest. Prog. Rep. 1956.

pp. 29-32.
FRY, DONALD H., JR.

1936a. A description of the eggs and larvae

of the Pacific mackerel (Pneumatopho-

rus diego). Calif. Fish Game 22: 28-

297
1936b. A preliminary summary of the life

history of the Pacific mackerel (Pneu-

matophorus diego). Calif. Fish Game

22: 30-39.
FRY, DONALD H., JR., and PHIL M. ROEDEL.
1949. Tagging experiments on the Pacific

mackerel (Pneumatophorus diego).

Calif. Div. Fish Game, Fish Bull. 73,

64 pp.

17

GRONOW, LAURENCE THEODORE.

1854. Catalogue of fish collected and de-
scribed by Laurence Theodore Gronow,
now in the British Museum. British
Museum, London, 196 pp.
HATANAKA, MASAYOSHI, and MASAO TAKA-
H.\HI.
1956. Utilization of food by mackerel, Pneu-
matophorus japonicus (Houttuyn). To-
huko J. Agr. Res. 7(1): 51-57.
HOUTUYN, M.

1782. Beschryving van eenige Japansche vis-
schen en andere zeeschepselen. Verh.
Holl. Maatsch. Wetensch., Haarlem,
20(2): 311-350.
JORDAN, DAVID STARR, and CHARLES
HENRY GILBERT.
1883. Note on a collection of fishes from
Charleston, South Carolina, with descrip-
tions of three new species. Proc. U.S. Nat.
Mus. 5: 580-620.
KRAMER, DAVID.

1960. Development of eggs and larvae of
Pacific mackerel and distribution and
abundance of larvae 1952-56. U.S. Fish
Wildl. Serv., Fish. Bull. 60: 393-438.
LINNAEUS, CAROLUS.

1758. Systema naturae. 10 ed. Laurentii
Salvii, Holmiae, 824 pp.
MacGREGOR, JOHN S.

1966. Synopsis on the biology of the jack
mackerel (Trachurus symmetricus).
U.S. Fish. Wildl. Serv., Spec. Sci. Rep.
Fish. 526, iii + 16 pp.

MATSUI, TETSUO.

1967. Review of the mackerel genera Scom-
ber and Rastrelliger with description of
a new species of Rastrelliger. Copeia,
1967: 71-83.
MESSERSMITH, J. D., and HAROLD HYATT.
1965. Pacific mackerel, the connmercial
fishery, and age composition of the
southern California catch for the 1961-
62, 1962-63and 1963-64 seasons. Calif.
Fish Game 51: 168-182.
ORTON, GRACE L.

1953. Development and nnigration of pigment
cells in some teleost fishes. J. Morph.
93: 69-89,
ROEDEL, PHIL M.

1952. A racial study of the Pacific macke-
rel, Pneumatophorus diego. Calif. Dep.
Fish Game, Fish Bull. 84, 53 pp.

1962. The names of certain marine fishes of
California. Calif. FishGame48: 19-34.

1963. The names of tunas and mackerels.
Calif. Fish Game 49: 119.

ROUNSEFELL, GEORGE A., and EDWTN H.
DAHLGREN.
1934. The occurrence of mackerel in Alaska.
Copeia, 1934: 42.
SCOFIELD, W. L.

1951. Purse seines and other round haul nets
in California. Calif. Dept. Fish Game,
Fish Bull. 81, 83 pp.
STARKS, EDWIN C.

1921. An inconsistency in taxonomy. Sci-
ence (Wash.) 54: 222-223.

MS. #1787

18

GPo eae- d7 0

SYNOPSES OF FISHERIES BIOLOGICAL DATA

This is one of a series of documents issued by FAO, CSIRO and USFWS concerning species and stocks of
aquatic organisms of present or potential economic interest. The primary purpose of this series is to make
existing information readily available to fishery scientists according to a standard pattern and by so doing
also to draw attention to gaps in knowledge. It is hoped that synopses in this series will be useful to otner

as revisions of the entire document or their specific chapters
The relevant series of documents are:
FAO

CSIRO
USFWS FAO

FR/S

FB/S

DFO/S

Fisheries Synopsis No.

(replacing, as from 1.1.63 FAO Fisheries Biology Synopsis)

Fisheries Synopsis No.

and
Fisheries Synopsis No. BCF/S

Synopses in these series are compiled according tea standard outline described in Flb/Sl Rev. 1 (1965).

FAO, CSIRO and USFWS are working to secure the co-operation of other organizations and of individual
scientists in drafting synopses on species about which they have knowledge, and welcome offers of help in
this task. Additions and corrections to synopses already issued will also be most welcome. Comments in-
cluding suggestions for the expansion of the outline and requests for information should be addressed to the
co-ordinators and editors of the issuing organizations:

FaO: Fishery Resources and Exploitation Division

Marine Biology and Environnnent Branch
Food and Agriculture Organization
of the United Nations

Via delle Terme di Caracalla
00100 Rome, Italy

USFWS: L. W. Scattergood

Chief, Branch of Reports

U.S. Department of the Interior
Fish and Wildlife Service

Bureau of Commercial Fisheries
1801 N Moore St.

Arlington, Va. 22209
U. S. A.

CSIRO: Maureen A. Wright

Scientific Editor

CSIRO Division of Fisheries and Oceanography
Box 21

Cronulla, N.S.W.
2230 Australia

lists of species or groups covered by synopses issued to date or in preparation will be
to time. Requests for copies of synopses should be addressed to the issuing organization.

The following synopses in this series have been issued since January 1968:

Synopsis of biological data on the Norway pout Trisopterus esmarkii
(Nilsson) 1855

FRi/S36 Synopsis of biological data on the bream Abramis brama (L.)

FRm/S34 Synopsis of biological data on the blue whiting Micromesistius

Rev. 1 poutassou (Risso) 1810.

FRm/S37 Synopsis of biological data on the Malayan anchovy Stolephorus

pseudoheterolobus Hardenberg 1933

FRiin/S38 Synopsis of biological data on Ascophvllum nodosum (Linnaeus)

Le Jolis

FRm/S39 Synopsis of biological data on Monostroma latissimum Wittrock in

Japanese cultivation

BCF/S40 Synopsis of biological data on the Pacific mackerel, Scomber japonicus

Houttuyn (Northeast Pacific)

Consolidated
issued from time

FRm/S33
Rev, 1

January 1968
February 1968

July 1968

April 1968

August 1968

August 1968

February 1969

As the Nation's principal conservation agency, the Depart-
ment of the Interior has basic responsibilities for water,
fish, wildlife, mineral, land, park, and recreational re-
sources. Indian and Territorial affairs are other major
concerns of America's "Department of Natural Resources."

The Department works to assure the wisest choice in
managing all our resources so each wiU make its full
contribution to a better United States — now and in the future.

UNITED STATES

DEPARTMENT OF THE INTERIOR

FISH AND WILDLIFE SERVICE

BUREAU OF COMMERCIAL FISHERIES

WASHINGTON, D.C 20240

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