This is the first annual report of the status of the spawning population of the Pacific mackerel as required by Section 8388.3 of the Fish and Game Code.

During 1972 and early 1973, several methods of determining population size were investigated as mechanisms for estimating the spawning population size of Pacific mackerel stocks north of Punta Eugenia, Baja California,

and a method using tagging procedures proved to be the most acceptable. The estimate of the Pacific mackerel spawning population obtained by tagging procedures was 5,480 tons. This estimate agrees generally with those obtained

from alternate methods in which previously computed spawning biomass estimates were correlated with partyboat catches in three different areas and the 1973 spawning biomass estimated from the resulting regression line. The estimates

derived by these alternate methods are 6,970 tons, 4,730 tons, and 6,210 tons.

All estimates are below the 10,000 ton spawning population minimum and thus there is no excess by which a harvest under Section 8388.5 of the Fish and Game Code could be allowed. (17pp.

Frey, Herbert W.

Knaggs, Eric H.

English

Aquatic Commons

LlaR ."..?':' 
Land;,,!; I."?',?. !i;tr,: 4; 2 ' s '  
S t a t e  of C a l i f o r n i a  p. (2 - 
THE RESOURCES AGENCY /&% Lzi ,' r ir' - " ' I , .  ':-J ; 
Department of F i s h  and Game 
STATUS OF PACIFIC MACKEREL 
SPAWNING POPULATION, 1973 
H e r b e r t  W. Frey 
and 
E r i c  H. Knaggs 
Marine Resources  Region 
FIRST ANNUAL PACIFIC MACKEREL REPORT 
MARINE RESOURCES 
A d m i n i s t r a t i v e  Report  No. 73-7 
J u l y  1973 
STATUS OF PACIFIC MACKEREL SPAWNING POFUIATION, 1 9 7 g  
SUMMARY AND IZ3COIGENWTIONS 
This i s  the f i r s t  annual repor t  of the  s t a tu s  of the spawning popula- 
t ion  of the  Pacif ic  mackerel a s  required by Section 8388.3 of the Fish and 
Csme Code. 
During 1972 and ea r ly  1973, several  methods of determining popula1;ion 
s i ze  were i n v e s t i e t e d  as mechanisms f o r  estimating the spawning population 
s i ze  of Pacif ic  mackerel stocks north of Punta Eugenia, Baja California, 
and a method using tagging procedures proved t o  be the most acceptable. The 
estimate of the  Pacif ic  mackerel spawning population obtained by tagging 
procedures was 5,480 tons. This estimate agrees generally with those obtained 
from a l t e rna t e  methods i n  which previously computed spawning biomass estimates 
were correla ted with partyboat catches i n  three d i f f e r en t  areas and the 1973 
spawning biomass estimated from the resu l t ing  regression l ine .  The estimates 
derived by these a l t e rna t e  methods a r e  6,970 tons, 4,730 tons, and 6,210 tons. 
A l l  estimates a r e  below the 10,000 ton spawning population minimum and 
thus there  i s  no excess by which a harvest  under Section 8388.5 of the  Fish 
and Game Code could be allowed. 
IP3TROIXICTION 
Pacif ic  mackerel, Scomber japonicus, occur from the Cul f  of Alaska 
southward i n t o  the Gulf of California. The species was never abundant north 
of Monterey Bay and i n  recent years has become scarce north of Point 
Conception. 
Prepared by Herbert W. Frey and Eric H. Knaggs, Marine Resources Region, 
350 Golden Shore, Long Beach, California 90802. 
The offshore extent  of P a c i f i c  mackerel spawning populations, as 
deduced from l a m  catches i s  about 150 miles off  southern California,  
250 miles off  northern Baja California,  and 200 miles of f  c e n t r a l  Baja 
California.  
Pac i f i c  mackerel are capable of moving great dis tances .  A tagging 
program conducted between 1935 and 1943 demonstrated t h a t  f i s h  from as far 
nor th  as Oregon and as f a r  south as c e n t r a l  Baja Cal i fornia  e n t e r  t h e  
southern Cal i fornia  f i shery .  Tag re turns  from t h e  southernmost regions 
i n  which f i s h  were tagged were r e l a t i v e l y  few and indicated  a reas  south 
of Point  Eugenia, Ebja Cal i fornia  ( ~ i g u r e  l), contributed 1ittl.e i f  
anything t o  the  California f i shery .  Results of an  ana lys i s  of mer i s t i c  
Figure 1. -Major po in t s  of reference  with respec t  t o  Pacific mackerel s tocks  
off  southern Ca l i fo rn ia  and nor thern  Baja  Cal i fo rn ia .  
counts and body proportion measurements indicated f i s h  from southern Baja 
California d i f f e r  radical ly  i n  many respects from f i s h  i n  the northern 
region. Fish t o  the south of Point Eugenia a r e  considered t o  be of a 
d i f f e r en t  stock; mingling l i t t l e ,  i f  a t  a l l ,  with those t o  the  north. 
As a result, Pacif ic  mackerel north of Point Eugenia a r e  considered a s  
a s ing le  stock as f a r  as management i s  concerned. 
The Pacif ic  mackerel fo r  years supported one of California 's  most 
important f i sher ies ,  contributing large tonnages (Figure 2). Iandings 
Year ,- 
Figure 2 .  California commercial landings of P a c i f i c  mackerel, 1926-1972. 
increased dramatically i n  the l a t e  1920ns, f e l l  off  i n  the depression years 
of the ear ly  1930's and then rose t o  a peak of 73,214 tons i n  1935. Since 
1936, commercial landings declined t o  a l o w  of 3,751 tons i n  1953, experi- 
enced a p a r t i a l  recovery during the period 1956 t o  1963, and have declined 
since then. A moratorium placed on commercial f i sh ing  i n  1970 was i n  
effect  u n t i l  1972, and since then a management l a w  has l imited the catches 
t o  only incidental ly  caught f ish .  In  1972 there were 54 tons (preliminary 
figure) of Pacif ic  mackerel landed t h a t  were taken incidental ly  with other  
catches. 
Pelagic f i she r i e s  off  Baja California have undergone considerable 
development since World War 11. Pac i f ic  mackerel landings remained f a i r l y  
s tab le  a t  2,000 t o  3,000 tons annually u n t i l  1955 when the catc:h rose 
sharply, and i n  1956 Mexican landings reached 13,000 tons. Following th i s ,  
landings again declined t o  a low l eve l  u n t i l  the  ear ly  and mid-1960's when 
large quant i t ies  of mackerel were again landed i n  Baja California. I n  1963 
over 11,000 tons of Pacific mackerel were landed, but landings had declined 
t o  only 16 tons i n  1971  able 1) .  Mexican landings have been taken 
pr incipal ly  from the extreme southern end of the stock's range, i n  the  
area of Sebastian Vizcaino Bay ( ~ i g u r e  l ) ,  near Punta Eugenia. 
Table 1. S t a t i s t i c a l  h t a  Pertaining t o  Baja California Pacif ic  
Mackerel Landings* 
Year Tons 
1966 6,500 
1967 1,072 
1968 184 
1969 289 
1970 555 
1971 16 
*hta from Mexican Fisheries Department, Ensenada, Baja California, Mexico 
Ocean sport anglers take thousands of Pacific mackerel each year. 
They are usually among the half-dozen species taken in greatest numbers 
in California's coastal waters. Partyboat landings accounted for 246,000 
Pacific mackerel (an estimated 125 tons) in 1972. This partyboat fishery 
has been monitored by the Department of Fish and Csme since 1947 (~i ~ u r e  3). 
Year 
Figure 3. California partyboat catches of Pacific mackerel, 
POFUIATION ESTIMATES 
The Department of Fish and Game is required to make an annual estimate 
of the spawning population of Pacific mackerel to comply with Section 8388.3 
of the Fish and Came Code (~ddenda 1). During 1972 and early 1973, several 
methods of determining population size were investigated as machanisms for 
estimating the spawning population size of Pacific mackerel stocks north of 
Punta Eugenia, Ba ja California. 
'm3ging 
The principle and most r e l i ab l e  estimate was made by using t ag  and 
recovery data (~ddenda 2). This method involves the release and recovery 
of tagged Pac i f ic  mackerel and the u t i l i z a t i o n  of age composition data from 
the partyboat catch t o  convert the t o t a l  population t o  a spawning population 
estimate. 
A t o t a l  of 1,472 Pacif ic  mackerel w a s  tagged during 1972. Marked 
f i s h  were recaptured not only near t h e i r  points of release, but a l s o  a 
considerable distance from these release points (~igure 4). 
Figure 4 .  Movements exhibited by tagged and recaptured Pacific. mackerel 
during 1972 and the f i r s t  5 months of 1973. 
The catch data  f o r  Fac i f i c  nzackerel were obtained from t h e  mobile 
partyboat f l e e t  onerat ing i n  Cal i fornia  and Lexican waters. Only tagged 
f i s h  receptured by the  partyboat f l e e t  were used t o  e s t i m t e  t h e  spawning 
po2uia-bion of ?acif ic  mackerel. 
estimated s i z e  of the Tacif'ic mackerel spawning population using 
tagging d a t e  i s  5,480 tons.  
Al ternat ive  TopA.ation Estimates 
Three o ther  s e t s  of data  were used t o  ca lcu la te  a d d i t i o n a l  esti.metes 
of Pac i f i c  mackerel spaTming biomass independent of the  tagging method. 
!Lie f i rs t  s e t  of da ta  consis ted  of partyboat landings of P a c i f i c  
mackerel captured i n  t h e  waters around Santa Catal ina Is land cor re la ted  
with corresponding e s t i n a t e s  of spawning population determined f o r  each 
year previous t o  1969. These data  .irere fit4Led with a t rend l i n e  
(Addenda 3 ) .  This s t a t i s t i c a l  t rend l i n e  i s  c a l l e d  a l i n e a r  regression 
using a l e a s t  squares fi-L. [The spaming  population est imate f o r  1973, 
a s  determined from t h e  regression l i n e ,  i s  6,970 tons .  
The second s e t  of da ta  consisted of partyboa-t landings of Pac i f i c  
aackere l  captured i n  %he waters around t h e  northern Channel Is lands  
 an Xiguel, Santa liosa, Janta  Cruz, and. Anacapa ~ s l a n d s )  . These da ta  
were a l s o  cor re la ted  with previously computed spawning popula-Lion e s t i -  
mates and f i t t e d  with a curved t rend l i n e  which i s  c a l l e d  a power curve 
(Addenda 4) .  The spawning population e s t i n a t e  f o r  t h i s  s e t  of da ta  is  
4,730 tons .  
The l a s t  s e t  of da ta  comgiled from c e n t r a l  Cal i fornia  partyboat catches 
was. used a s  an ind ica to r  of ;2opulation s i z e .  Tnese da ta  were f i t t e d  with a 
l i n e a r  regress ion  l i n e  using a l e a s t  squares f i t  (ltddenda 5 ) .  l! spami- 
ing >opd-at ion of 6,210 tons  was calcula ted  from this s e t  of da ta .  
The 2 a c i f i c  Laackerel resource scsncs a good chance of becoming 
reha;.i,ili cated i n  Cal i fornia  under presen ;nana.genient uraczi ces . iVhile 
the IJacific m c k e r e l  :?opulat5on decl ined LO an extremely low l e v e l  dur- 
ing  J i e  l3jO's due t o  e car.foination of poor recruiblnent and high f i s h i n g  
pressure, r ec ru i tmnt ,  success i n  recent  years  gives reason f o r  gaarded 
on t in i sn .  Any re1akionsili-p between recruitmen'; and s s w n i n g  populat ion 
i s  03viouslJ7 a f fec ted  'uy ocher f a c t o r s .  Large variance i n  recruitlilent 
r e s u l t i n g   fro:^ a given spawring p o y l a t i o n  can occur becatlse of environ- 
zlental f a c t o r s .  '1nese environmental f a c t o r s  can be adverse and rnay be 
p a r t  of the reason f o r  good year c l a s ses  f a l l i n g  zo anpear and f o r  t h e  
presenc diminutive spaiming sxock of 5,480 tons .  
7ne 1963 year c l a s s  vhen i'irst rec ru i t ed  appeared strong,  u ; .  de- 
c l ined ra?idly,  an6 contr ibuted l i t t l e  t o  :he spawning populat,on, 
al-liiough iL yes the  s t ronges t  year c l a s s  i n  may years.  The 1939 year 
c l a s s  was s n a l l ,  but  the  1970 year c l a s s ,  presumably spawned by <he 1963 
survivors,  i s  very s t rong  and conlprFses a l a r g e  gor t ion  of the ;>resent 
spawning population. ?he l 9 i l  year c l a s s  again was small,  and while it 
is s t 5 1 1  too  e a r l y  t o  eva lua -~e ,  the  19?(2 year  c l a s s  has made afi e a r l y  
showing i n  i n c i d e n ~ z l  conmercial catches and shows promise. Tne 1970 
year  c l a s s  is  approaching f u l l  maturi ty and provides f o r  recrui7.;aent 
success i n  1973 and 1974. 
ADDENDA 1 
Sect ions  of C a l i f o r n i a  Fish and Game Code 
Pe r t a in ing  t o  P a c i f i c  Mackerel 
8388. Except a s  provided i n  Sec t ion  8388.5, P a c i f i c  mackerel may not  
be taken o r  possessed a t  any time f o r  any purpose except  loads  o r  l o t s  of 
f i s h  may conta in  18 percent  o r  l e s s  by weight of P a c i f i c  mackerel taken 
i n c i d e n t a l l y  t o  o t h e r  f i s h i n g  opera t ions .  Such P a c i f i c  mackerel, inciden-  
t a l l y  taken, may be used f o r  any purpose. (Amended by S t a t s .  1972, Ch. 608.) 
8388.3. It is t h e  i n t e n t  of t h e  L e g i s l a t u r e  t h a t  t h e  P a c i f i c  mackerel 
resource be enhanced. During t h i s  process  a  f i s h e r y  s h a l l  be allowed once 
t h e  P a c i f i c  mackerel spawning populat ion,  i n  wa te r s  n o r t h  of Punta Eugenia, 
Baja Ca l i fo rn i a ,  Mexico, has  reached 10,000 tons  a s  determined by t h e  
department. Such determinat ion s h a l l  be made pub l i c  i n  an annual r epo r t  
t o  t he  L e g i s l a t u r e  no l a t e r  than J u l y  31 of each year .  It is  a l s o  the  
i n t e n t  t h a t  a s  t h e  spawning populat ion inc reases ,  i n  excess  of 20,000 tons ,  
t h e  seasonal  quota a l s o  be increased  bu t  a t  such a  r a t e  a s  t o  a l low t h e  
continued i n c r e a s e  i n  t he  P a c i f i c  mackerel populat ion.  This process  
should cont inue  wi th  t h e  o b j e c t i v e  of maximizing t h e  sus t a ined  ha rves t .  
(Added by S t a t s .  1972, Ch. 608.) 
8388.5. Sec t ion  8388 s h a l l  remain i n  e f f e c t  u n t i l  t h e  department 
determines t h a t  t h e  es t imated  P a c i f i c  mackerel spawning populat ion,  i n  
wa te r s  no r th  of Punta Eugenia, Baja Ca l i fo rn i a ,  Mexico, exceeds 10,000 
tons .  When t h e  department makes t h i s  determinat ion,  a  season ha rves t  quota 
equal  t o  20 percent  of t h e  amount of P a c i f i c  mackerel i n  excess  of 10,000 
t ons  spawning populat ion,  a s  determined by t h e  department, s h a l l  be permi t ted  
under permits  i s sued  by t h e  department. 
When t h e  department determines t h a t  t h e  spawning populat ion exceeds 
20,000 tons,  t h e  ha rves t  quota s h a l l  be inc reased  t o  30 percent  of t he  
excess  over 20,000 tons. 
The department s h a l l  keep records of t h e  ca tch  of P a c i f i c  mackerel and 
when i t  appears  t h a t  the  season quota w i l l  be reached, it s h a l l  n o t i f y  a l l  
permit  ho lders  of t h e  da t e  when such l i m i t  w i l l  b e  reached and t h e r e f o r e  
t h e  season c losed ,  and s h a l l  n o t i f y ,  by c e r t i f i e d  m a i l ,  a l l  permit  ho lde r s  
of such c losu re .  ( ~ d d e d  by S t a t s .  1972, Ch. 608.) 
8388.7. Subject  t o  t h e  provis ions  of Sec t ions  8388 and 8388.5, P a c i f i c  
mackerel season is  from October 1 through September 30. (Added by S t a t s .  
1972, Ch. 608.) 
ADDENDA 2 
E s t i m a t e s  of P a c i f i c  Mackerel  Spawning 
Biomass Using Tagging (Mark and Recapture)  Methods 
The t o t a l  biomass was c a l c u l a t e d  u s i n g  t h e  equa t ion :  
P = Cn2 (mtu) / Cnm 
where: P = biomass estimate i n  numbers of f i s h .  
n = number of marked f i s h  r e l e a s e d  i n t o  t h e  p o p u l a t i o n .  
m = number of marked f i s h  r e c a p t u r e d .  
u = number o f  unmarked f i s h  r e c a p t u r e d .  
The v a l u e s  f o r  t h e  e q u a t i o n  were c a l c u l a t e d  t o  be: 
1n2(ml-u):= 2.017618822 X 1011 
Cnm := 13061 
w i t h  t h e  biomass e s t i m a t e  i n  numbers being:  
P = Cn2 (ntl-u) / Cnm 
P = 2.01761882 X 1 0 ~ ~ / 1 3 0 6 1  
P = 15,447,660 f i s h  
Convers ion t o  pounds i s  accomplished by m u l t i p l y i n g  t h e  number of f i s h  
t i m e s  t h e  average  weigh t  of f i s h  sampled. 
P = 15,447,660 f i s h  X 1.0210 pounds 
P = 15,772,060 pounds 
The e s t i m a t e d  p r o p o r t i o n  o f  spawning biomass (determined from a g e  samples)  
t o  t o t a l  biomass i s  .69444; t h e r e f o r e :  
Spawning biomass = 15,772,060 X .69444 
= 10,952,750 pounds 
= 5,476 t o n s  
(5,480) 
ADDENDA 3 
Est imates  of P a c i f i c  Mackerel Spawning Biomass 
Using Partyboat  Catch from t h e  Waters o f f  Santa Cata l ina  I s l and  
The spawning biomass was c a l c u l a t e d  us ing  a  l e a s t  square e s t ima te  of 
and 6 f i t t e d  t o  t h e  l i n e  y  = i+6x 
where: y = biomass e s t ima te  i n  thousands of pounds. 
x  = number of P a c i f i c  mackerel caught o f f  Santa  Cata l ina  
I s l and .  
2 = c o e f f i c i e n t  
- 
b = c o e f f i c i e n t  
The c o e f f i c i e n t s  a and 6 were c a l c u l a t e d  by us ing  t h e  fol lowing 
equat ions:  
A nCxy - (Cx) (Cy) b  = 
nzx2 - (zx12 
A c o r r e l a t i o n  c o e f f i c i e n t  was a l s o  c a l c u l a t e d  us ing  t h e  formula: 
The va lues  of t h e  c o e f f i c i e n t s  and t h e  c o r r e l a t i o n  c o e f f i c i e n t  a r e  
c a l c u l a t e d  t o  be: 
wi th  t h e  spawning biomass e s t i m a t e  f o r  1973 being: 
y  = 13,931,668 pounds 
y  = 6,966 tons  
(6,970) 
ADDENDA 4 
Estimates  of P a c i f i c  Mackerel Spawning Biomass 
Using Partyboat  Catch Data from t h e  Waters 
o f f  t h e  Northern Channel I s l a n d s  
The spawning biomass was c a l c u l a t e d  us ing  a  non-l inear  regress ion:  
l e a s t  squares  f i t  power curve. Data p o i n t s  were f i t t e d  t o  t h e  formula: 
y  = ax b 
where: y  = biomass e s t ima te  i n  thousands of pounds 
X = number of P a c i f i c  mackerel caught o f f  t h e  no r the rn  
Channel I s l a n d s  
a  = c o e f f i c i e n t  
b  = c o e f f i c i e n t  
The c o e f f i c i e n t s  a  and b  were c a l c u l a t e d  by using t h e  fol lowing equat ions:  
n Z (LOG x. LOG y.)  - (I: LOGexi) (2 LOC;,yi) 
e i e i 
n 2 n 2 
n Z (LOGexi) - (I: LOG x.) 
1 1 e I 
n n 
a = exp [i 1 I: LOGeyi - ( 2  LOG x.)b 
1 1 1 I 
A c o r r e l a t i o n  c o e f f i c i e n t  was a l s o  c a l c u l a t e d  using t h e  formula: 
n 2 (LOGexi LOGeyi) - ( 2  LOGcxi) ( 2  LOG Y.) 
1 1 1 e i 
The values of t h e  c o e f f i c i e n t s  and t h e  c o r r e l a t i o n  c o e f f i c i e n t  a r e  
ca l cu la t ed  t o  be: 
with the  biomass e s t ima te  f o r  1973 being: 
y = axb 
= .008309748 (194) 2.647169714 
= 9,457,738 pounds 
= 4,729 tons  
(4,730) 
ADDENDA 5 
Est imates  of P a c i f i c  Mackerel Spawning 
Using Cen t r a l  C a l i f o r n i a  Partyboat  Catch 
a s  an I n d i c a t o r  of Populat ion S ize  
The spawning biomass was c a l c u l a t e d  using a  non-l inear  regress ion:  
l e a s t  squares  f i t  power curve. Data po in t s  were f i t t e d  t o  t h e  formula: 
y  = a x  b  
where: y  = biomass e s t ima te  i n  thousands of pounds 
X = number of P a c i f i c  mackerel caught off  c e n t r a l  C a l i f o r n i a  
from par tyboats  
a  = c o e f f i c i e n t  
b  = c o e f f i c i e n t  
The c o e f f i c i e n t s  a  and b  were c a l c u l a t e d  by using t h e  fol lowing 
equat ions  : 
n 2 n 
n 2 (LOG x,) - (Z LOG x.) 2 
1 e i 1 
n n 
a = exp [i 1 LOG y - (2 LOG x.)b 
I e i  1 e i 1 I 
A c o r r e l a t i o n  c o e f f i c i e n t  was a l s o  c a l c u l a t e d  using t h e  formula: 
n n n 
n 2 (LOG X. LOGeyi) - (2: LOGeXi) ( 2  LOGeYi) 
1 e i 1 1 
r = - - 
n 2 n 2 d [n (L0G.x.J - (Z LOGex$] [ n  2 ( L o G d $  - (2 L O G e ~ $  1 1 
The v a l u e s  o f  t h e  c o e f f i c i e n t s  and t h e  c o r r e l a t i o n  c o e f f i c i e n t  a r e  
c a l c u l a t e d  t o  be: 
w i t h  t h e  biomass estimate f o r  1973 being:  
b y = ax 
= 651.9752438 (117) .6 18724486 
= 12,412,759 pounds 
= 6,206 t o n s  
(6,210) 


Status of Pacific Mackerel spawning population, 1973

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Status of Pacific Mackerel spawning population, 1973

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