EALffDRFnS
FBH^GAME
f Volume 36
San Francisco, July, 1950
Number 3 1
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TO OUR SUBSCRIBERS
The Division of Fish and Game is making an effort to furnish to libraries
back issues of California Fish and Game which are missing from their files. If you
have extra copies or copies of back issues which you do not use. It would be
greatly appreciated if you would return them to the Public Information Office,
Division of Fish and Game, Ferry Building, San Francisco, in order that we may
complete these library sets, thereby making available to a great many readers
copies which are no longer available for distribution.
STATE OF CALIFORNIA
DEPARTMENT OF NATURAL RESOURCES
DIVISION OF FISH AND GAME
San Francisco, California
EARL WARREN
Governor
WARREN T. HANNUM
Director of Natural Resources
FISH AND GAME COMMISSION
HARVEY E. HASTAIN, President
Brav/ley
PAUL DENNY, Commissioner LEE F. PAYNE, Commissioner
Etna Los Angeles
WILLIAM J. SILVA, Commissioner
Modesto
E. L. MACAULAY
Executive Officer
San Francisco
CALIFORNIA FISH AND GAME
PHIL M. ROEDEL, Editor Terminal Island
Editorial Board
RICHARD S. CROKER San Francisco
WILLIAM A. DILL Fresno
JOHN E. CHATTIN San Francisco
CaKfornin Fish and Game is a journal devoted to the conservation of wildlife
which is published quarterly by the California Division of Fish and Game Contributions
Thould be sent to Mr. Phil M. Roedel, Editor, State Fisheries Laboratory. Terminal
Island Station, San Pedro, California. Manuscripts must be typed, double spaced, and
conform to the style of previous issues.
The articles appearing herein are not copyrighted and may be reproduced else-
where, provided due credit is given the authors and the California Division of Fish and
Game.
This periodical is sent free of charge to interested persons, who may have their
names placed on the mailing list by writing to the editor. Subscriptions must be renewed
annually by returning the postcard included with each October issue. Subscriber.s art-
requested to notify the editor immediately of changes in address, giving the old address
as well as the new.
California Fish and Gamf
rn],f • . ^^^^^ °^ CONTENTS
a" Evaluation of Postal Card v ^"^^'^>'S -
^ ' - ird A on response
Food Habits of a California Deer Herd ^- ^- ^'^^houx J 77
Age and Length Compositio" ^T '"' ''°"^«^^ «• ^^^^^^^ 235
Coast of the United States and Can."/' •^'^'^'^•^' ^-^^" ^»^^ ^^^'^^"
-f «-^^'CEsE. Felix AviTAFn^^
Basic Deer Management (A kt'Z^:^'-^'''''^^''^' ^"^1 L^o Pix
(A Story With Pictures) ^ ""'' """^ '''â– "''''' -"^^
The Pismo Clam William P. Dasmaxv 051
faWo™,a Antelope Kep.„d„..iveP„ten,iah
-Vote. „„ Two Species of ^l^nZZ^^'^:'::' ,''»-''- LxssE.v 328
ornia
I^HdoJph Gerhardt ^^^
f red W. Hecker
J-^^'l r Hiscox 334
Jl'Miiy Ocker __ ^^^
Rr'vi.-w r__~ 334
-^" niustrated Kev to fh„ T- , ~~ ^^^
,, ^^'-t. bv Jay m'^^ ^ - ^^S Snakes and Turtles of the
Keports -' Hehhkrt L. Haoex
'EX 336
337
(37G)
CALIFORNIA ANGLING CATCH RECORDS FROM
POSTAL CARD SURVEYS: 1936 1948; WITH AN
EVALUATION OF POSTAL CARD
NONRESPONSE *
By A. J. Calhoun t
Bureau of Fish Conservation
California Division of Fish and Game
TABLE OF CONTENTS
Page
Introduction 177
I'AKT I — California angling catch records from state-wide postal card surveys 179
Principal California angling trends 180
General discussion of catch and angler estimates 182
Trends in California trout angling 182
Trout catch and angler estimates for 104S including zero catches 188
Trout angling effort and success in 1948 189
County distribution of the 1948 trout catch 190
Migrations of California trout anglers in 1948 191
Trends in California striped bass angling 192
Other striped bass estimates 196
Records for warm-water fishes 196
Salmon catch records 207
PART II — An evaluation of postal card and nonresponse in California angling
catch surveys 210
Comparison of general characteristics of personal interview respondents who
did and did not return postal cards 213
Comparison of general estimates of numbers of anglers fishing and days fished 215
Statistical comparisons and fiducial limits of mean catch estimates 216
Statistical comparisons and fiducial limits of percentages of licensees angling
for various fish 224
Statistical comparisons and fiducial limits of total catch estimates 227
Comparison of numbers of anglers fishing for trout in different parts of Cali-
fornia 228
Comparison of trout angler migration patterns 229
The validity of the individual postal card reports 230
Summary 232
References 233
Appendixes 233
INTRODUCTION /
Valuable estimates of numbers of anglers fishing in California each
year as well as the number of fish they catch are provided by special
Division of Fish and Game surveys. These angling inventories enable
California's fisheries administrators to evaluate the results of their
efforts to improve fishing. They have also made it possible to follow the
explosive increase in angling pressure which has taken place since the
war. These surveys have the additional important function of providing
reliable information about the striped bass fishery as a whole. Striped
bass are harvested over an extensive area throughout the year by several
hundred thousand anglers, and it is impractical to obtain complete
records by means of creel checks or other field methods.
In making these state-wide angling surveys, return postal cards like
the one shown in Figure 53 are mailed to a random sample of the anglers
Submitted for publication April, 1950.
t Figures were drawn by Miss Margaret Chadwick. Charles Paya assisted with
calculations.
(177)
178
CALIFORXIA FISir
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ANGLING CATCH RECORDS, 1 936- 1 948 179
licensed in California during- a calendar year.* About one-tliird of the
recipients respond, with yreat regularity. Such a return is large enough
to show major trends in numbers of fish caught and numbers of fisher-
men, because survey methods are standardized. The trends obtained
undoubtedly jiarallel the actual changes Avhich are taking y)laco. On the
other hand, there has always been nnicli uncertainty about the numerical
catch estimates, one reason being that it seemed improbable that indi-
viduals who returned questionnaires were representative of the general
angling population. This matter was given special attention in 1048. A
special personal interview survey was made that year to determine the
influence of nonresponse upon estimates of various kinds, with rather
surprising results. In general, the individuals who returned cards actu-
ally were found to be highly representative of the angling public as a
whole. No important warping of mean catches, total catches, numbers of
anglers or trout angler migrations resulted from postal card non-
response, which is clearly not an important source of error in these
estimates. It is therefore now possible to place increased confidence in
them.
This report has a double purpose. The whole series of California
angling catch surveys from 1936 to 1948, inclusive, is summarized in
Part I. The special 1948 study of nonresponse is discussed in Part IT. A
later report by II. Iljersman will cover a parallel personal interview
survey of 1948 hunting in California, which had essentially similar
results.
The matter of nonresponse in these California surveys has been
settled for the present, but the partner question of the validity of the
individual angler reports remains to plague us. This problem is also
discussed in Part II, in the light of the 1948 personal interview survey.
PART I— CALIFORNIA ANGLING CATCH RECORDS FROM
STATE-WIDE POSTAL CARD SURVEYS
This program has had an interesting history. It originated from a
desire on the part of California fish and game administrators for reason-
ably accurate estimates of yearly angling catches. Brian Curtis con-
ducted the surveys for the years up to and including 1944. The author
analyzed the returns from the 1944 survej^ and has been responsible for
the program since then.
Any data in this article for surveys prior to 1944 have been extracted
from unpublished reports by Curtis. Similar hunting surveys have
been conducted independently from time to time (Hunter and Frv,
1940, 1941).
In the early years of these surveys, from 1935 to and including 1939,
all individuals who obtained a California angling license were asked
at the time of purchase to fill in a detailed questionnaire about their
fishing .success during the previous year. Roughly a third complied. At
the end of the year the reports were collected from the license agents
throughout California and the catches were then machine-tabulated to
derive state-wide angling catch estimates.
This license stub method had certain serious disadvantages. The
catch estimates were not usually obtained for about two years, because
* Anj^lers too young to reQuire a license do not enter the sample. The minimum
age was 18 until 1947 and 16 subsequently.
"^'Sri AND GAME
Resume of r = / ■* • "'"ABLE 1
^^L^^rn,. State-W.de Ang.in
i'ear
Type of survey
1935* I t;
1936 J^.'ccnfie jtub
1937 .Hfeose stub
1938 .HW'westub
1939 |-.'"'"se stub
1939 m"?'?''"''
1942 "â– '^''^''''carj
1040 fostalcard
1W4 J'ostalcard,
1946 M°*'"' «^^dt
1947 postal card
1040 None
J9«:::::- ^'-'^
Number of
licensed
anglers
223,098
298,736
312.m
346,661
366,452
9 Catch Survey
Questionnaire recipients
388,472
453,159
433,431
445,416
436,940
554,027
766,753
S84,772
Interview. .V" ' " " " | +960,027
•The 193;
Numlj(
All
All
All
All
All
32,224
None
39,738
39,306
41,610
9,318
None
29,862
None
18,070
1,250
Percent of aij
licensees
100
100
100
100
100
8.8
Usable returns
Number
87,103
76,520
90,481
104,982
109,701
9,609
Percent of all
recipients
38.9
25.6
28.9
30.3
30.0
29.8
9.1
9.4
2.1
13,569
11,552
12,899
2,761
3.9
34.1
29.4
31.0
29.6
8,874
1.9
0.13
29.7
5,751
1,250
31.8
100.0
inal figure.
PRINCIPAL CAUFOR,
ubseciuent discussions because it was
â– 'duals purchasing- lie
icenses in nine
eeent year.s.
ANGLING CATCH RECORDS, 1 936- 1 948
TABLE 2
Total Angling Pressure in California, 1935-1948
181
Year
Total license
sales
Average fishinf?
days per angler
Total fishing
(lays
1935
223,098
346,661
453,159
433,431
445,416
766,753
t960,027
No data
No data
14.2
14.3
12.9
13.5
15.4
•3,120,000
Ii)3X -
•4.K50,0()0
1941
6,410,000
1942 . -
6,1HO,000
ii)4:i
5,750,000
1946 -
10,350,000
1948
14,700,000
* Fourteen fishingr days per anplor used in e.stimating this.
t Not the final figure.
1935 1938 1941 1944
Figure 54. Total numher of California angling days.
1947
except for a brief levelling-off during the war. There has been about a
five-fold increase in total angling pressure in California since 1935.
Onl}' a small part of this upward trend can be attributed to recent regu-
lations rof|uiring an angling license for the taking of catfish and certain
marine fishes not previously covered and lowering the minimum age at
which a license is required.
It is not surprising that the success of individual anglers has
declined as their numbers have increased. This has been the general
trend for all types of angling. It has probably been at least partly the
direct result of fishing pressure. More people have had to share the
available crop of fish each year, and their individual shares have
decreased accordingly. Another factor has been the large number of
inexperienced newcomers to California, who have had to learn how and
where to fish before competing on equal terms witli long-time residents
of the State.
Although the general trends of angling success are similar for all
kinds of fresh-water and anadromous game fishes for which there are
records, there is nevertheless considerable variation among them. They
182 CALIFORNIA FISH AND GAME
will therefore be discussed separately in the summary of the postal card
records which follows. This summary consists in large part of statistical
tables and graphs. Much of it is important primarily as reference
material, licadcrs who are more interested in the general aspects of
surveys of this sort than in the detailed results obtained in California
are referred especially to Part II, which takes up the 1948 study of non-
response at length.
GENERAL DISCUSSION OF CATCH AND ANGLER ESTIMATES
The three principal trends obtained from these surveys for each
kind of fish are the inimber of successful anglers, the average annual
catch per angler, and the total catch. It is necessary to deal throughout
with successful anglers rather than with the more general category of
all anglers fishing for a species. Fishing days and numbers of anglers
fishing unsuccessfully for the various kinds of fish cannot be obtained
without unduly complicating the questionnaire and making it unsuit-
able for a postal card. As a result, postal card fishing effort figures are
rather broad estimates, based on the nund)er of anglers actually catch-
ing a given kind of fish in the course of the year. From all indications
such estimates approximate the true figures rather closely.
The other two trends also have their limitations. The average
annual catch per angler is based on a large number of approximations
made by indivithial anglers. It can be assumed quite safely that few
anglers will remember exactly how many fish of various kinds they
caught during the preceding year. Comparison of a series of double
postal card and interview reports made by the same anglers in 1948
reveals that some indi\idua]s give surprisingly different answers to the
same questions on two occasions only a few weeks apart. However, in
general the correlation between paired reports from the same individual
was fairly high. The discrepancies occurred more or less at random, and
tended to average out, with the end result that the average catch figures
obtained for the same group on different occasions were generally in
reasonably close agreement. These data are discussed in greater detail in
Part II.
The limitations of the average catch estimates apply in equal measure
to the total catch estimates, which are based upon them.
A great deal can be learned from these three trends, in spite of their
limitations, which have been emphasized to prevent the reader from
assuming that they are in the same class with comparable figures based
on complete and objective catch records.
It is important to bear in mind, while reading the pages that follow,
that the primary value of postal card catch per unit of effort estimates
lies in the picture they provide of general angler success. For many
reasons they are not very good indexes of abundance of the fish involved.
The whole matter of the statistical reliability and fiducial limits of
the various types of estimates obtained from these surveys is of great
interest. However, it is quite technical, and has therefore been included
in Part II.
TRENDS IN CALIFORNIA TROUT ANGLING
Trout angling far outstrips all other types in iiojuilarity among
California anglers. Any doubt about this was removed by the 1948 per-
sonal interview survey. One of the questions asked a random sample of
ANGLTXG CATCH RECORDS, 1 936- 1 948
183
California aiiplf^rs was, " Wliicli of tlic kinds of fish on tliat card do you
like best to fish for?" The kinds of fisli on tlic card and percent a j^-cs
favorin'*' eacli arc shown in Tabic •'!. Ahimsl b;df of tiw wlioh' ;jfoup
favored either trout or sleelliead trout. It will ;dso be seen fi'Oin the
fourth coliinin of Table 4 that this preference is actually expressed in
anjilin^'. lion;^hly '>() percent of all California anj;ling licensees catch
trout each year, and tlie 11)48 interview survey revealed that in most
cases these were the same individuals who placed trout fir.st on their list
of favorites.
TABLE 3
Fishing Preferences of California Anglers
Percent of total
sample
profcrrinK
indicated fish
Percent of total
sample
preferring
indicated fish
Steelhead trout
Other trout
Salmon (ocean)
Salmon (river).
Striped bass...
Black bass
Crappie
Sunfish
7.2
39.9
2.1
3.6
13.0
9.7
1.7
0.5
Catfish
Barracuda
Abalone
Other ocean fish
No preference..
Total
4.5
4.4
1.1
7.7
4.6
100.0
• Includes in order of mention : Albacore, yellowtail, halibut, corbina, tuna, rock-
fish, and 20 others.
TABLE 4
Trends in California
Trout Angling
Total catch
Successful anglers
Annual catch per successful
angler
Year
Number
Percent of
angling
licensees
Mean
Median
1936 . - -
12,000,000
11,900,000
12,900,000
12,800,000
15,700,000
16,400,000
15,700,000
17,660,000
18.400,000
149,000
151,000
160,000
179,000
238,000
234.000
213,000
357,000
415,000
50
48
46
49
53
54
48
47
43
80
78
79
71
66
70
75
49
44
50
1937
50
1938
SO
1939
37
1941
40
1942 - -
42
1943 :
37
1946
25
1948 -
20
It is of interest to note that about the same proportion of all
licensees have fished for trout each year since 1936, in spite of the great
increase in the total number of anglers. Apparently the newcomers have
fallen closely into the established pattern of California angling.
The continuing increase in trout anglers each year is graphed in the
middle panel of Figure 55. Their numbers have almost tripled since 1936.
There has been an accompanying increase of about 50 percent in the total
annual trout catch, shown in the bottom graph. However, this latter
increase has by no means kept i)ace with rising angling jiressure. The top
graph shows the sharp drop in the average annual trout catch per angler
since 1943, when angling pressure began to increase most rapidly. These
trout catch and angler estimates are summarized in Table 4.
Individual trout catches reported each year range all the way from
one to a thousand or more. The mean (average) catch per successful
angler has declined over the years from 80 in 1936 to 44 in 1948, as will
184
CALIFORXIA FISH AND GAME
100
OT
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1936
1939
1942
1945
1948
a:
400,000
UJ
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300,000
U.
cn
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111
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200,000
C/)
u.
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cr
100,000
Z
3
Z
1936
1939
1942
1945
1948
15,000,000
X
CO
b.
O 10,000,000 —
OQ
spoo.ooo —
1936 1939 1942 1945
Figure 55. California trout angling: trends.
1948
ANGLlNa CATCH RECORDS, 1 936- I 948
185
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40
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/936
50 100 150 300
ANNUAL TROUT CATCH
700
100 150 300
ANNUAL TROUT CATCH
700
1
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CO
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1946
I
1-
^ 30
1 yWedian 25
PERCENT OF
; >;::\ yMeon 58
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Figure. 56.
100 150 300
ANNUAL TROUT CATCH
700
50
D
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1948
\ -Medion 20
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50 100 150 300
ANNUAL TROUT CATCH
700
Percentage frequencies of trout anglers by numbers of trout caught in
various years.
186 CALIFORNIA FISH AND GAME
be seen from Table 4. However, the mean catch is not a very good index
of the general fishing success of anglers, because the catch frequency dis-
tributions are so strongly skowod that only about a fourth of all trout
anglers take tiie average catch or more. The graphs in Figure 56 illustrate
this point very well. They represent the smoothed frequency distribu-
tions of all trout angl(M-s bv the number of trout thev caught annually
during the years ]9;5{i, l<):{f), 1!)43, l!)4(i, and ]948. The curves for 1939
and lf)48 are almost identical, and the two are represented in this figure
by the 1939 curve. Anglers who fished for trout but caught none are
omitted fi-om these distributions because they do not report such fishing
on the questioiniaires. Class intervals of 20 trout were used in preparing
these graphs.
These frequency curves are all stronglj^ J-shaped. In all cases
more anglers caught from 1 to 20 trout than caught from 21 to 40.
Similarly, more reported 41 to 60 than 61 to 80, and so on down the line ;
there are ])rogressively fewer individuals in each succeeding category.
The same type of curve is obtained when the data are plotted ungrouped.
Such curves are also characteristic of other species, for which
examples are given in Part II.
Because of the peculiar shape of these curves the median catch is
a more meaningful measure of individual angler success than is the
mean. The median catch in 1948 was only 20 trout. In other words,
roughly half of all successful trout anglers caught less than 20 trout and
the other half caught more. In the 1948 personal interview survey the
number of unsuccessful anglers was determined, and the median for all
trout anglers, including those who caught none, was only 12 fish. The
median catches from postal card surveys in the earlier j^ears are also
listed in Table 4.
The four curves in Figure 56 show the great changes w4iich have
occurred in the over-all picture of the success of individual California
trout anglers during the past 13 years. The median catch, indicated by
a solid vertical line, has shifted progressively to the left until in 1948
it is less than half the lf)36 figure. The mean, shown by the broken line,
has made a comparable shift. The solid black area to the left under these
curves represtMits the least .successful one-fourth of trout anglers. Catches
of this group ranged from 1 to 20 in 1939 but were only from 1 to 8 in
3948. It will be recalled that unsuccessful trout anglers do not report
as such in these postal card surveys, so there are no zero catches repre-
sented. Their inclusion would undoubtedly have further intensified the
shift to the left shown in these curves. The black area to the right repre-
sents the most successful one-fourth of trout anglers. This group con-
sisted of anglers catching 100 or more trout in 1939, but in 1948 the lower
limit had dropped to 50. The hatched area at the extreme right of each
is plotted on a class interval of 200 trout. It shows the change in the
relative numbers of anglers reporting very large catches consisting of
200 or more trout. This group does not seem to have decreased as greatly
as might have been expected.
The recent rapid decline in the success of individual trout anglers
tipjiears to have resulted ])rimarily from the addition of several hundred
thou.sand i-elatively unsuccessful anglers to the original group present
in 1936. This is certainly suggested by Figure 57, which shows the first
and last graphs from the preceding figure plotted by actual numbers of
ANGLING CATCH RECORDS, 1 936- 1 948
187
240,000
200,000
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160,000
120,000 —
80,000
40,000
ANNUAL TROUT CATCH