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CAUFORNIAI
FTSH-GAME

"CONSERVATION OF WILDLIFE THROUGH EDUCATION"



California Fish and Game is a journal devoted to the con-
servation of wildlife. Its contents may be reproduced elsewhere
provided credit is given the authors and the California Depart-
ment of Fish and Game.

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their applications. Subscriptions must be renewed annually by
returning the postcard enclosed with each October issue. Sub-
scribers are asked to report changes in address without delay.

Please direct correspondence to:

JOHN E. FITCH, Editor
State Fisheries Laboratory
511 Tuna Street
Terminal Island, California

Individuals and organizations who do not qualify for the free
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individual issues for $0.75 per copy by placing their orders with
the Printing Division, Documents Section, Sacramento 14, Cali-
fornia. Money orders or checks should be made out to Printing
Division, Documents Section.



u







VOLUME 49



APRIL 1963







NUMBER 2




Published Quarterly by

THE RESOURCES AGENCY OF CALIFORNIA

CALIFORNIA DEPARTMENT OF FISH AND GAME

SACRAMENTO



STATE OF CALIFORNIA

EDMUND G. BROWN, Governor

THE RESOURCES AGENCY OF CALIFORNIA

HUGO FISHER, Adminisiraior



FISH AND GAME CO/AMISSION

JAMIE H. SMITH, President

WILLIAM P. ELSER, Member HENRY CLINESCHMIDT, Vice President

San Diego Redding

DANTE J. NOMELLINI, Member THOMAS H. RICHARDS, JR., Member



Stockton



Sacramento



DEPARTMENT OF FISH AND GAME

WALTER T. SHANNON, Direcfor

OFFICE— FISH AND GAME COAAMISSION

722 Capitol Avenue
Sacramento 14



OFFICES— DEPARTMENT OF FISH AND GAME

722 Capitol Avenue

Sacramento 14



1001 Jedsmith Drive
Sacramento

1234 East Shaw Avenue
Fresno

627 Cypress Street
Redding



Ferry Building
San Francisco

217 West First Street
Los Angeles

51 1 Tuna Street
Terminal Island

407 West Line Street
Bishop



271 Tyler Street
Monterey

619 Second Street
Eureka

Room 12, North Ramp

Broadway Pier Building

San Diego



CALIFORNIA FISH AND GAME

Editorial Staff

JOHN E. FITCH, Editor-in-Chief - _

DAVID P. BORGESON, Editor for Inland Fisheries -.

ALBERT E. NAYLOR, Editor for Game

JOHN L. BAXTER, Editor for Marine Resources

DONALD H. FRY, JR., Editor for Salmon and Steelhead ._



-Terminal Island

Sacramento

Sacramento

...Terminal Island
Sacramento



(62)



TABLE OF CONTENTS

Page

An Evaluation of Five Tag Types Used in a Striped Bass Mor-
tality Rate and Migration Study Harold K. Chadwick 64

Commercial Freshwater Fisheries of CaliioTma^Sterling P. Davis 84

Brush Manipulation on a Deer "Winter Range

R. P. Oihhens and A. M. Schultz 95

Note

The Names of Tunas and Mackerels Phil M. Roedel 119

Reviews 120



(63)



AN EVALUATION OF FIVE TAG TYPES USED IN

A STRIPED BASS MORTALITY RATE AND

MIGRATION STUDY'

HAROLD K. CHADWICK

Inland Fisheries Branch
California Department of Fish and Game

INTRODUCTION

Tagging is one of the more important techniques used to study fish
populations and the primary technique selected for a 1958-1961 study
of the mortality rates and migrations of striped bass, Boccus saxatilis,
inhabiting the Sacramento-Sau Joaquin River system and the San
Francisco Bay area in California.

Four qualities that tags must possess if valid results are to be ob-
tained from their use are :

a) They must not affect mortality.

b) They must not affect the fish 's A'ulnerability to fishing gear.

c) They must not be shed.

d) They must be easily recognizable and contain sufficient instruc-
tions so the person catching the fish will see and know what to
do Avith the tags.

Using these criteria five kinds of tags are evaluated in this paper.

Many tag types have been used in fish population studies, but none
lias been universally acceptable (Rounsefell and Everhart, 1953). In
most previous striped bass studies, Petersen disk tags have been used
(Clark. 1984; Pearson, 1938; Merriman, 1941; Morgan and Gerlach,
1950; Calhoun. 1952; Vladykov and Wallace, 1952; Calhoun, 1953).
Generally the tags were shed quite rapidly, making them unsatisfactory
for mortality rate studies. The shedding was caused partly by attach-
ment at unsatisfactory locations on the fish (Calhoun, Fry and Hughes.
1951 ; Calhoun, 1953). However, relatively few of even the best-designed
Petersen disk tags used by Calhoun were returned after the first year,
indicating they were probably being shed (Chadwick, 1962).

The only other tag type used on striped bass before the present study
was an internal one (Merriman, 1911; Raney. 1952). Although it
offered promise, the difficulty of recovering this type of tag from the
California sportfishery was believed insurmountable.

The promising results with disk-dangler tags (modified Atkins tags)
on striped bass (Calhoun, 1953), on white catfish, Ictahirus catus,
(Pelgen and McCammon, 1955), and on largemouth bass, Micropterns
salmoides, (Kimsey, 1956, 1957) suggested that they might be the best

1 Submitted for publication August 1962. This study was performed as part of Dingell-
Johnson Project California F-9-R, "A Study of Sturgeon and Striped Bass", sup-
ported by Federal Aid to Fish Restoration funds.



(64)



TAG TYPE EVALUATION 65

tags available for striped bass. Consequently, they were selected as the
standard tag for this study.

Other studies suggested that "spaghetti" tags (Wilson, 1953; Coll-
yer, 1954; Kimsey, 1956) or Einer Lea hydrostatic tags (Kimsey, 1956;
McCammon, 1956) might prove suitable, so they were tested. Work
subsequent to the start of this study indicated that dart tags ( Yamashita
and Waldron, 1958) and streamer tags (David, 1959) might be suitable,
so they were also included.

Most of my information about these tags was obtained by tagging
groups of striped bass from the main population in the Sacramento-
San Joaquin River system. Most of the bass were caught with gill nets
in the Sacramento and San Joaquin rivers near Antioch during the
spring spawning migration (Chadwick, 1960).

Since recoveries were from a sportfishery scattered over a Avide area,
biologists were able to examine few^ tagged bass. To obtain additional
information about the condition of tagged fish, a postal card question-
naire (Figure 1) was sent to each angler returning a tag during 1959
Tag No. and 1960. The questions asked were subjec-

tive, so the replies were of value only for

(Check one) ' comparativc purposes.

The reliability of different kinds of tags

was also tested by tagging landlocked striped

sught sore, not serious. ^^^^ -j^ g^^^ J ^^^^^ Wastcway, au irrlgatlou

bad sore. caual ucar Los Banos, California. These were

tagged in a wastcway pond that was about 200
Was thure a large amount of moss f ect wldc, 200 yards loug, aud a maxlmum of

or^other material attached to the -^q ^^^^ ^^^^ (FigUrC 2). MaUy of thC baSS

Yes No tagged there could be recovered periodically

by seining. Most were double-tagged and this
was essential, since wounds from shed tags
frequently healed so perfectly no external

Any further comments' evidcncc of tagglug could bc seen.

FIGURE 1. Postal cord ques- Limited information was also obtained by

tionnaire sent to anglers return- obscrviug a fcW tagged baSS in a 1,000-gallon

ing tags. aquarium.

Since conditions in San Lnis Wasteway and the acquarium were
vastly different from the natural environment, the results were not
comparable to those in the Sacramento-San Joaquin River, but they
did provide useful information.



Condition of flesh around tag
neck one)

no sign of a sore



If yes, please describe it.



66



CALIFOENIA FISH AND GAME






FIGURE 2. Seining at San Luis Wasteway to recapture tagged striped bass for examination.

Photograph by George Nofces, March 1961.



DISK-DANGLER TAGS
Description and Application

The disk-dangler tag, originally described by Calhoun (1953), con-
sists of a plastic disk (Figure 3A) attached with a double wire. All
of our disks were made of cellulose nitrate 0.04 inches thick and 0.5
inches in diameter and consisted of three layers — a middle opaque
white layer with the printing, laminated between two clear layers.

Three types of wire were tested : pure tantalum 0.020 and 0.025
inches in diameter and Type 302 soft stainless steel 0.020 inches in
diameter.

The tags were placed about halfway between the lateral line and the
base of the first dorsal fin under the longest spines. They were applied
to unanesthetized bass in a canvas tagging cradle by pushing two 17-
gauge, 3i-inch hypodermic needles through the fish, threading the two
tag wires back through the needles as they were pulled out, twisting
the two ends of the wire together, and cutting off the excess with a
pair of pliers (Figure 4). The posterior wire was placed perpendicular
to the midline of the body. The anterior wire was inserted at an angle,
so it came out at the same point as the posterior wire on the tag side, and
I to 1 inch away from the posterior wire on the other side. This arrange-
ment is believed to improve stabilization of the wires in the flesh (Kim-
sey, 1956).

Tagging Studies

About 16,000 striped bass were marked with disk-dangler tags be-
tween 1958 and 1961, most in the lower portions of the Sacramento and
San Joaquin rivers near Antioch, but some farther upstream at Verona



TAG TYPE EVALUATION



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CALIFORNIA FISH AND GAME




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FIGURE 4. Tagging operation with bass in cradle and needles inserted through back. Wire on
tag is being threaded back through needles. Phofograph by William Dillinger, May 1961.

on the Sacramento River and at Prisoner's Point on the San Joaquin
River. Others were tagged farther downstream in San Pablo Bay.

During the spring of 1958, comparative tests were made with 0.025-
inch and 0.020-inch tantalum wire and 0.020-inch stainless steel wire.
The comparative tests with 0.020-inch tantalum and 0.020-inch stain-
less steel wire were repeated during the springs of 1959 and 1960. The
wire types being tested were used on alternate tags when being applied
in a 1 :1 ratio, or in the appropriate order when another ratio was used.

In addition to the regular field studies, 126 striped bass were tagged
with disk-danglers at San Luis Wasteway during the late winters of
1958, 1959, and 1960. Both 0.020-inch tantalum and 0.020-inch stainless
steel wires were used. Most tish were also marked with a second tag to
measure shedding.

Ten bass tagged with disk-danglers in March 1961 were held for
observation in a 1,000-gallon aquarium.

Evaluation of Results

Comparison of Three Kinds of Wire

The returns from field experiments with the three types of wire are
summarized in Tables 1 and 2. A chi-square test indicates there is no
significant difference between the returns of tantalum 0.020 and tanta-
lum 0.025 wire (f = 0.37, d.f. = 1, P a^ 0.58). For the 1958 tags, the
stainless steel wire returns were significant!}" greater than the returns
of tantalum 0.020 wire tags (/^ — 5.15^ d.f. = 1, P = 0.02). However,
the opposite was true for the 1960 tags when the returns of tantalum
0.020 wire were substantially greater than those of stainless steel wire



TAO TYPE EVALTJATIOX ()[)

{-f = 3.43, d.f. = 1, P r= 0.07). Returns from the 1959 tags were ap-
proximately equal for the two wires, so the differences were probably
due to chance variations, indicating the overall effects of shedding, mor-
tality, and vulnerability changes were equal in these tests.

TABLE 1

Returns from Striped Bass Tagged During the Spring of 1958 Near Antioch with
Disk-Dangler Tags Attached with Tantalum Wire 0.020 and 0.025

Inches in Diameter

: 0.020 Tantalum 0.025 Tantalum

- Number Percent Number Percent

Tagged 549 _ 560

First-year returns 128 23 119 21

Second-year returns 36 7 34 6

Third-year returns 11 2 16 3

Total returns 175 32 169 30

TABLE 2

Returns from Striped Bass Tagged Near Antioch with Disk-Dangler Tags Having
Tantalum and Stainless Steel Wire 0.02 Inches in Diameter

1958 Tags 1959 Tags 1960 Tags

Tantalum Stainless Tantalum Stainless Tantalum Stainless



No. Pet. No. Pet. No. Pet. No. Pet. No. Pet. No. Pet.

Tagged 1,212 1,802 1,734 1,545 1,809 1,809

P^irst-year returns 231 19 392 22 260 15 238 15 278 15 239 13

Second-year returns __ 51 4 93 5 150 9 140 9 _- __ _^ __

Third-year returns 30 2 47 3 _^ ._ __ __ ^_ __ __ __

Total returns 312 26 532 30 410 24 378 24 278 15 239 13

TABLE 3

Degree of Irritation Caused by Disk-Dangler Tags with Three Types of Wire,
OS Indicated by Postal Card Questionnaires

Type 302 soft
Tantalum tvire Tantalum wire stainless steel ivire
0.020" diameter 0.025" diameter 0.020" diameter

Percentage having no sore 53.6 44.3 57.2

Percentage having slight sore 39.7 41.8 33.4

Percentage having bad sore 6.7 13.9 9.5



Total tags 1,219 79 88



The postal card questionnaires also indicated there was little differ-
ence in the irritation caused by stainless steel 0.020 and tantalum 0.020
wires (Table 3). Greater irritation was indicated for the tantalum
0.025 wire, but the number of replies was too small to permit valid
conclusions.

Comparisons of the degree of irritation with the elapsed time be-
tween tagging and recapture for stainless steel and tantalum 0.020-inch
wire indicate a static relationship (Table 4). While this does not neces-
sarily indicate a static degree of irritation on an individual fish, it does
indicate considerable continuing irritation with both wire kinds, and
no overall trend of worsening or improvement in the degree of irrita-
tion.

The six 0.020 stainless steel wire and four 0.020 tantalum wire disk-
dangler tags on the aquarium bass gave similar results. Within 10
months all 10 wires adhered firmly to the flesh, and in all but one of
each the skin had grown completely over the wire knot.



70 CALIFORNIA FISH AND GAME



TABLE 4



Degree of Irritation Caused by Disk-Dangler Tags with 0.020-Inch Tantalum Wire and

Type 302 Soft Stainless Steel Wire and the Elapsed Time Between Tagging

and Recapture, as Indicated by Postal Card Questionnaires *

Elapsed Tantalum wire Stainless steel wire

time Slight sore Bad sore Slight sore Bad sore

(days) (percent) (percent) Total tags (percent) (percent) Total tags

0- 89 33.3 6.4 141 27.7 9.9 141

90-179 44.9 10.8 185 34.9 9.0 189

180-269 46.2 7.6 158 33.8 12.0 133

270-369 39.8 8.9 123 38.1 12.2 147

370-459 26.4 2.3 87 29.4 8.2 85

460-549 30.0 7.8 90 37.8 4.9 103

550-639 46.3 7.3 41 26.5 8.8 34

640-999 32.4 5.9 34 30.9 7.3 55

* To avoid bias, only tags put on during spring months were used. No stainless steel wires were used during
tiie fall.

However, there was evidence, primarily from San Luis Wasteway,
that the wires are not equal in all respects. The only stainless steel wire
tags used there were put on in March 1960. Of 14 bass observed a year
later, none had shed its tag. On 10 of the 14, the skin had grown over
the knot and healed completely, and the wires were firmly anchored in
the flesh of 9 of the 14.

Somewhat different results were obtained there with 0.020 tantalum
wire tags, which were put on in January 1958 and February and March
1959. Tags on 4 of the 41 bass recovered within a year had been shed,
and the wire on a fifth broke at the disk when the fish struggled in a
dip-net. Twenty-three of these were recovered again at the end of the
second year; one more tag had been shed and the wire broke on two
others as they struggled in the dip-net.

The skin had healed over the knot on only 10 of the 37 tantalum
wire tags examined at the end of the first year, but this appears quite
variable, since in one group, 8 out of 14 had healed over, while in the
other group only 2 out of 23 had healed. At the end of the second
year, the skin had healed over the knot in 14 of the 21 fish observed.
On 17 of 18 fish, tantalum wire had adhered firmly to the flesh by the
end of the first year.

These results indicate tantalum wire tags have a greater tendency to
shed than do stainless steel wire tags, probably because of the lower
tensile strength of tantalum wire. Tantalum wires adhere to the flesh
more rapidly but the skin grows over the knot more slowly. These
factors may be related, since if tags are not firmly secured the wire
tends to pull into the flesh until it becomes anchored on pterygiophores
and neural spines. Hence, the knot is no longer in a position to irritate
and prevent healing.

Bass tagged in the Delta and examined after recapture showed a
similar tendency for the skin to grow over the wound on the knot side
more rapidly with stainless steel wires than with tantalum — 13 out of
16 of the former and 17 of 29 of the latter being healed.

Shedding Rate

In addition to the tantalum wire tags shed at San Luis "Wasteway,
both stainless steel and tantalum wire disk-danglers were shed by
striped bass tagged in the Delta. An angler caught a bass with the



TAG TYPE EVALUATION 71

tantalum wire broken and the disk gone ; one tantalum wire broke and
the tag pulled out when a bass was caught in a gill net two years after
tagging; one stainless steel wire was recovered with a section corroded
away and the disk gone ; three stainless steel wire tags were pulled off
in gill nets 6 months to 2 years after tagging ; an angler was reported
to have caught a bass with the wire present but no disk; and a bass
was seen with a tag scar but no tag. These observations are, of course,
inadequate for estimating the rate of shedding.

The returns of disk-danglers from Delta tagging in 1958 declined
sharply after the first year (Table 5). However, the low initial return
and the more gradual rate of decline for 1959 and 1960 returns and
evidence of non-returns of angler-caught tagged fish, suggest this
difference was due to a higher angling mortality in 1958, rather than
a greater shedding rate.

TABLE 5

Yearly Returns of Striped Bass Tagged with Disk-Dangler Tags in
the Delta Near Antioch During 1958, 1959, and 1960

First-year Second-year Third-year Fourth-year

No. tagged returns returns returns returns

1958 4,228 952 218 107 33*

1959 3,279 498 290 96*

1960 3,618 517 227*

* Partial returns including only those received to 1/12/62.

However, tag returns suggested that tagged fish survival declined
with time. For example, during 1959 survival indicated by the 1959 tag
group was 0.58 while survival indicated by the 1958 tag group was
only 0.44. In 1960, survival indicated by the 1960, 1959, and 1958 tag
groups was 0.44, 0.33, and 0.31. Possible explanations for this are: (1)
the rate of shedding increases with time, and (2) older fish suffer a
higher natural mortality or lower angling mortality. The first- and sec-
ond-year returns of the 1958 and 1959 tags (Table 6) indicate that older
(larger) fish did have a higher total mortality in 1958, but not in
1959. The total mortality differences in 1958 were largely due to the
angling mortality differences described above, so an increasing shedding
rate is the most logical explanation.

TABLE 6

First Year Survival indicated by Tag Returns from
Various Length Groups of Striped Bass
Fork length Year tagged

in inches 1958 1959

15-18 0.29 0.57

19-20 0.28 0.60

21-22 0.26 0.51

23-24 0.17 0.74

25-27 0.20 0.52

28-t- 0.14 0.50

• Includes only non-reward disk-dangler tags from bass tagged near Antioch.

Effects on Mortality and Growth

There is no direct evidence of substantial mortality caused by tag-
ging, but disk-dangler tags do lower the growth rate. In calculating
striped bass growth rates, only measurements made by biologists were
used. Expected growth was calculated using average annual increments



72



CALIFORNIA FISH AND GAME



determined by a recent growth study (Robinson, 1960) and assuming
that growth occurred linearly from May through October. This is ob-
viously an imperfect procedure, especially since all measurements were
to the nearest inch and the sexes of most fish were unknovsTi. However,
the preponderance of negative deviations from mean growth (Table 7)
is substantial evidence that these tags slow a fish's growth.



TABLE 7
Growth of Striped Bass Tagged with Dislc-Dangler Tags



Deviation from

average growth Numier

in inches offish

more than +1.4 2

+1.0 to 1.4 3

+ 0.5 to 0.9 3

+0.4 to —0.4 15

—0.5 to —0.9 14



Deviation from

average growth

in inches


Number
of fish


—1.0 to —1.4


8


—1.5 to —1.9


.. 5


—2.0 to —2.4


3


more than — 2.4


5



Scales taken from three bass at the time of tagging were compared
with scales taken from the same fish two years later. These indicated
the growth rate declined after tagging, but there apparently was no
traumatic upset at the time of tagging (Figure 5).






^



,T-^-^W;







FIGURE 5. Scale from a striped bass which was 19 inches long when taggecJ June 10, 1959,

and 24 inches long when recaptured April 17, 1961. Annul! marked by white lines. Third

onnulus was forming at time fish was tagged and the fifth was forming on the margin when

recapfured. Photographed by William Schafer, April 1962.



TAG TYPE EVALUATION



78



A comparison of the growth of two tagged bass with untagged bass
from the 1956 year-class (in the spring of 1961) indicated the two
tagged fish grew unusually slowly the first year after tagging, but
that growth was normal during the second year (Table 8). No generali-
zations can be made, however, because of the small sample size.

TABLE 8

Fourth- and Fifth-Year Scale Growth of Two Tagged and Several
Untagged Striped Bass from the 1956 Year-Class

Scale Increment *
Tagged basis Tagged bass Mean of J 4

G-rowthyeur #1 #2 uniagged 9 $

4 y 10 21

5 12 12 IP.

* Measured along anterior radius and (.'xini'ssed as a percentage of tlie radius.



Mean uf 12
untagged cT c^

20
12



Degree of Irritation Caused by Tags

The decrease in growth is probably associated with the irritation
caused by the tag. The degree of irritation was quite variable : some
fish healed completely, while others possessed irritated areas several
inches long behind the tags. At San Luis AVasteway and in the Delta
the irritation was frequently chronic and static. The tagged bass in
the aquarium never rubbed their tags or gave any indication of irrita-
tion, despite the fact that some developed disk-sized sores, sensitive to
the touch, under the tags.

The causes of tag irritation are not completely known. The obvious
primary cause in many instances was the disk and wires rubbing
against the fish. The most common result of irritation was an excoriated
circular patch under the disk. The position of the tag when it stabilized
in the flesh contributed to the degree of irritation. In some fish, the


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