The life history and ecology of largemouth bass in Parker Canyon Lake
Item Type text; Thesis-Reproduction (electronic)
Authors Saiki, Michael K. (Michael Kenichi), 1949-
Publisher The University of Arizona.
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Link to Item http://hdl.handle.net/10150/566486 THE LIFE HISTORY AND ECOLOGY OF LARGEMOUTH
BASS IN PARKER CANYON LAKE
by
Michael Kenichi Saiki
A Thesis Submitted to the Faculty of the
DEPARTMENT OF BIOLOGICAL SCIENCES
In Partial Fulfillm ent of the Requirements For the Degree of
MASTER OF SCIENCE WITH A MAJOR IN FISHERY BIOLOGY
In the Graduate College
THE UNIVERSITY OF ARIZONA
19 7 3 STATEMENT BY AUTHOR
This thesis has been submitted in partial fulfillm ent of re quirements for an advanced degree at The University of Arizona and is deposited in the University Library to be made available to borrowers under rules of the Library.
Brief quotations from this thesis are allowable without special permission, provided that accurate acknowledgment of source is made. Requests for permission for extended quotation from or reproduction of this manuscript in whole or in part may be granted by the head of the major department or the Dean of the Graduate College when in his judg ment the proposed use of the m aterial is in the interests of scholar ship. In all other instances, however, permission must be obtained from the author.
SIGNED:
APPROVAL BY THESIS DIRECTOR
3 /?7J ^ CHARLES ZIEBELL ~ ^ 2 - D ate Lecturer of Biological Sciences ACKNOWLEDGMENTS
I wish to express my appreciation to Mr. Charles D. Ziebell
for serving as my major professor. I also thank Dr. Howard R. Pulliam,
Dr. Elisabeth A. Stull, and Dr. Jerry C. Tash for their valuable c riti
cism of the manuscript. Mr. Steve Alcorn, Mr. Robert Hallock, Mr.
David Kennedy, Mr. Marlyn M iller, and Mr. Mark Singer helped with the
field collections and their assistance is appreciated.
The study was supported by the Arizona Cooperative Fishery Unit
in cooperation with The University of Arizona, the Arizona Game and
Fish Department, and the U. S. Bureau of Sport Fisheries and W ildlife.
iii TABLE OF CONTENTS
Page
LIST OF T A B L E S ...... v i
LIST OF ILLUSTRATIONS...... v i i
A B ST R A C T ...... v i i i
INTRODUCTION ...... 1
DESCRIPTION OF THE STUDY A R EA ...... 3
METHODS AND MATERIALS ...... 5
P h y s ic o -c h e m ic a l W ater Q u a lity A n a ly s is ...... 5 B ass and F o ra g e I n v e r t e b r a t e C o l l e c t io n s ...... 6 R e p ro d u c tiv e P o t e n t i a l ...... 7 O b s e r v a tio n s ...... 7 Food H a b i t s ...... 7 Age, Growth, and Length-weight Relationships ...... 8
RESULTS...... 12
P h y s ic o -c h e m ic a l W ater Q u a lity C o n d itio n s ...... 12 R e p ro d u c tiv e P o t e n t i a l ...... 16 Spaw ning ...... 16 Observations of Fry and Fingerlings ...... 19 Available Fish Forage Invertebrates ...... 20 Food H a b i t s ...... 22 A ge, G row th, and L e n g th -w e ig h t R e l a ti o n s h i p s ...... 29 H a b i ta t U t i l i z a t i o n ...... 31
D IS C U S S IO N ...... 35
R e p ro d u c tiv e P o t e n t i a l and Spaw ning S u c c e ss ...... 35 Factors Affecting Bass Food Habits ...... 38 F a c to r s I n f lu e n c i n g G row th ...... 40 Im p o rta n c e o f th e L i t t o r a l W e e d s ...... 45
CONCLUSION...... 47
APPENDIX A: CLASSIFICATION SCHEME OF INVERTEBRATES ...... 48
iv V
TABLE OF CONTENTS— C o n tin u e d
Page
APPENDIX B: FECUNDITY VARIATIONS IN BASS TAKEN IN MARCH AND APRIL 1972 ...... 50
LIST OF REFERENCES 51 LIST OF TABLES
Table Page
1. Sexual maturity stages of bass collected from M arch - May 1972 17
2. Benthic invertebrate composition at various w a te r d e p t h s ...... 21
3. Littoral weed invertebrate composition and esti mated seasonal relative abundance ...... 23
4. Primary and secondary foods of bass during the s p r in g (M arch - M a y ) ...... 25
5. Primary and secondary foods of bass during the summer (Ju n e - A u g u st) ...... 26
6. Primary and secondary foods of bass during the f a l l (S ep tem b er - N o v e m b e r) ...... 27
7. Primary and secondary foods of bass during the w in te r (D ecem ber - F e b r u a r y ) ...... 28
8. Calculated growth rates of 1969 - 1971 bass y e a r c l a s s e s ...... 30
9. Growth of largemouth bass in Parker Canyon Lake and in o t h e r l o c a l i t i e s ...... 43
vi LIST OF ILLUSTRATIONS
Figure Page
1. Map of study area and locations of sampling s t a t i o n s ...... 4
2. Bass body length - anterior scale radius rela t io n s h i p ...... 10
3. Bass standard length - total length relation s h ip ...... 11
4. Monthly temperature and oxygen stratification p a t t e r n s ...... 13
5. Monthly pH and total alkalinity stratification p a t t e r n s ...... 14
6. Annual Secchi disk and lake level fluctuation p a t t e r n s ...... 15
7. Bass spawning areas ...... 18
8. Counts of crayfish 2.5 cm long or larger from t h r e e s h o r e l i n e s t a t i o n s ...... 24
9. Growth rates and size ranges of young-of-the- y e a r ...... 32
10. Bass length-weight relationship ...... 33
vii ABSTRACT
The life history and ecology of largemouth bass in Parker
Canyon Lake was studied from 1971-1972 to provide information for fu
ture management. Emphasis was placed upon reproductive potentials,
spawning, food habits, growth rates, and habitat utilization.
Females matured when two or three years old and exhibited fe
cundities ranging up to 69,000 eggs. Successful spawning occurred in
O mid- or late May when water temperatures approximated 20 C. Nests were
constructed in shallow water, on flat or gradually sloping bottoms. Fry
terminated their schooling behavior when they reached 2.2 to 3.3 cm
standard length. Diets varied with fish size. Fry fed on zooplankton
while larger bass fed on insects, fish, and crayfish, respectively.
Seasonal variations were also observed. Prior to 1970, juveniles grew
rapidly but stunting occurred in older fish. The proliferation of
crayfish in 1970 apparently terminated the stunting. Bass hatched be
tween 1969-1971 grew well. Mean total lengths of 28.0 cm and weights
of 348.4 g were attained after three years. The growing season was
calculated to range from six to ten months. Littoral weeds served as
the major food producing region and also provided protective cover.
viii INTRODUCTION
The human population of southeastern Arizona has increased in
the last 10 to 15 years, causing greater demands for water-based recre-
• ation, especially fishing, in a region typically devoid of natural
lakes and permanent streams. To alleviate this problem, artificial
lakes such as Parker Canyon Lake were constructed. Lake building, how
ever, is costly and not always feasible in many areas. For these rea
sons, maximum use of existing artificial lakes through efficient
management practices is desirable. Such management practices should
be based upon the condition of the fishery and pertinent ecological
factors affecting the fishery.
A fishery can be evaluated on the basis of the rate at which
catchable-sized fish become available to the angler. In a sustained
yield fishery, this rate would be dependent upon successful spawning
and growth. If strong year classes are continuously produced and
growth is fairly rapid, a good fishery will result.
Successful spawning and growth are directly related to ecologi
cal factors such as physical and chemical water quality, and the avail
ability of spawning grounds and forage foods. If any of these factors
are substandard or absent when they are required, the whole fishery can
be impaired.
The broad objectives of this study were to examine the large-
mouth bass fishery of Parker Canyon Lake and some of the ecological
1 factors which could affect the well-being of the fishery. The study began in November 1971 and terminated in October 1972. Specific objec
tives included investigations of the following:
1. Water quality
2. Bass reproductive potential and spawning
3. Available forage invertebrates
4. Bass food habits
5. Bass age, growth, and length-weight relationships
6. Bass habitat utilization DESCRIPTION OF THE STUDY AREA
Parker Canyon Lake is located in Santa Cruz and Cochise coun
ties, in southeastern Arizona, at an elevation of 1636 meters. It is
• approximately 56 kilometers east of Nogales and 10 kilometers north of
the U.S. - Mexico border.
The lake basin is L-shaped (Fig. 1) with the long axis extend
ing in a north-south direction. The surface area of the lake at spill
way level is 74 hectares. Rooted aquatic plants, especially Myriophyl-
lum exalbescens, are very abundant along the lake shore with annual
die-offs occurring in the late fall and winter. Further physical and
limnological descriptions of the lake have been given by Bergersen
(1 9 6 9 ).
The summer fishery is dominated by largemouth bass (Micropterus
salmoides). green sunfish (Lepomis cyanellus). bluegills (L. macro-
chirus), and channel catfish (ictalurus punctatus). During the winter,
rainbow trout (Salmo gairdneri) stocked from state hatcheries become
important. Several other game species are present only in lim ited num
bers and contribute little to the fishery at the present time. These
include redear sunfish (Lepomis microlophus). brown trout (Salmo tru tta).
and coho salmon (Oncorhynchus kisutch). Forage fish most commonly en
countered are threadfin shad (Dorosoma petenense) and mosquito fish
(Gambusia affin is).
3 PARKER CANYON LAKE
SAMPLING STATIONS: # Water Quality # Benthic Invertebrates # Littoral Weed Invertebrates EE Crayfish fA Bass
Dam
Spillway
Figure 1. Map of study area and locations of sampling stations. METHODS AND MATERIALS
The methods and m aterials employed in this study were chosen on
the basis of the type of data they would yield, the availability of the necessary equipment, and the time lim its available for data collection.
The methods were usually modeled after procedures designed by other in vestigators but when such procedures proved inadequate, they were
either modified or redesigned.
Physico-chemical Water Quality Analysis
Water samples were collected monthly at a station located ap
proximately 50 meters east of the dam (Fig. 1) from just below the sur
face to a depth of 15 meters. Sampling time was always near mid-day.
Dissolved oxygen and temperatures were obtained with a portable
YSI oxygen-temperature meter at one-meter intervals. Occasionally this
instrument was not available and samples were collected with a Kemmerer water sampler at five-meter intervals with oxygen determined by the
azide m odification of the Winkler method (American Public Health Asso
ciation 1965). .Temperatures were taken with a portable YSI telether mometer at one-meter intervals.
Samples for total alkalinity and pH were collected with a Kem merer water sampler at five-meter intervals. Total alkalinity was de
termined by the procedure of Rainwater and Thatcher (i960). A portable
Beckman pH meter was used for all pH determinations.
5 6
The depth of light penetration was measured with a standard
Secchi disk on a calibrated line. The lake level was recorded from a water gauge at the southwestern end of the lake whenever water quality data was collected.
Bass and Forage Invertebrate Collections
All samples were collected on a monthly basis at stations shown in Figure 1. During the summer and fall months, fish were collected more frequently.
Bass were sampled by electrofishing at night, and seining and dip-netting during the day. Infrequent gillnet sets were also made throughout the study period. All fish were preserved immediately in
10% formalin for subsequent laboratory analysis.
Benthic invertebrates were sampled from various depths with an
Ekman dredge. Littoral weed invertebrates were collected with a long- handled, fine mesh dip-net by sweeping the net through submerged aquatic weed beds. Samples were placed in labeled glass jars and stored on ice until examined in the laboratory. All invertebrates were identified by using keys in Pennak (1953) and Usinger (1956) and clas sified according to the scheme presented in Appendix A.
Crayfish counts were made at night along three shoreline sta tions with a six-volt flashlight. The area observed extended lakeward from shore for approximately two meters and down to depths approaching one-half meter. 7
Reproductive Potential
An idea of the reproductive potential of the bass population was obtained through studies of the sex ratio, sexual m aturity, and fecundity. These determinations were based upon procedures by Bagenal and Braum (1968), Bennett (1948), and Kelley (1962). Bass were col lected throughout the year to determine their sex ratios. However specimens for sexual m aturity determinations were collected between
March and May while specimens for the fecundity study were collected between March and A pril.
Observations
Observations of spawning, schooling fry, and habitats utilized by bass were made from a boat during daylight hours.
Food Habits
The stomach contents of all bass were removed from the poste rior portion of the esophagus to the pyloric sphincter and identified using keys from Eddy (1969), Pennak (1953), and Usinger (1956). Fre quency of occurrence (Lagler 1956) and mean bulk index were criteria used to indicate the relative importance of the groups of organisms consumed. Only stomachs containing food were considered. The bulk index of each group of food organisms was established by visually exam ining the relative size of the groups in individual bass stomachs. The groups were then subjectively rated 1 through 9 with 1 indicating the greatest bulk. A rating of 10 meant that the organism was absent. The mean bulk index was then calculated from the equation: 8 SR MBI N where MBI = mean bulk index of the organism, R = numerical rating of the organism from individual stomachs, and N = total number of "full" sto m a c h s.
Foods ingested were analyzed on the basis of the fish length and season. Bass less than 10.0 cm standard length (S.L,) were divided into 1.0 cm intervals while bass 10.0 to 19.9 cm S.L. were divided into
5.0 cm intervals. All bass 20.0 cm S.L. and larger were grouped to g e th e r .
Age, Growth, and Length-weight Relationships
The standard and total lengths of bass were measured to the nearest 0.1 cm on a standard measuring board. Damp-dry weights were measured to the nearest 0.1 g on a triple beam balance.
Aging and back-calculations of growth were derived from scales showing one or more annuli. Scales were removed from the left side of the fish between the posterior region of the pectoral fin up to the lateral line before the fish were preserved. In the laboratory, the
scales were cleaned and dry-mounted between glass slides, then magni fied 30.5 times with a microprojector. The annuli were counted and distances between the focus, annuli, and the anterior scale margin were measured to the nearest 0.01 cm.
Back-calculations of growth were determined using the equation
s 1 = c + (1 - c) n s 9 where 1 = S.L. of the fish at the time of the annulus formation,
1 = S.L. of the fish at time of capture, c = constant, s^ = length of
the anterior radius of the scale at the n^1 annulus, and s = length of
the anterior scale radius at capture (Tesch 1968). The constant (c)
was derived from the body—scale relationship (Tesch 1968) of 407 bass
grouped into 1.0 cm intervals from 4.0 to 32.0 cm S.L. The S.L. of
each group was then plotted against the corresponding mean length of
the anterior scale radius (Fig. 2) and the linear regression equation
(M iller 1966) was expressed as
L = 0 .7 cm + 1 .8 S
where L = S.L., S = anterior scale radius X 30.5, and 0.7 cm = c.
Growth rates of young-of-the-year bass were determined by aver
aging the standard lengths of all fry and fingerlings caught during
each sampling trip.
To facilitate growth comparisons with the literature, an equa
tion for converting S.L. to total length (T.L.) was computed from 727 '
bass (Fig. 3). The linear regression equation was
T.L. « 0.4 cm + 1.2 S.L.
The length-weight relationship was described from the formula
log W = log a + b log L
where W = weight, L = S.L., and a and b = constants (Lagler 1956). 10
- s
MEAN SCALE RADIUS (CM) X 30.5
Figure 2. Bass body length - anterior scale radius relationship. Cfl 25
MEAN STANDARD LENGTH (CM)
Figure 3. Bass standard length - total length relationship. RESULTS
Selected life history and ecological factors which influenced
the largemouth bass fishery at Parker Canyon Lake w ill be presented in
the following order: physico-chemical water quality conditions; repro ductive potential; spawning; observations of fry and fingerlings; available fish forage invertebrates; food habits; age, growth, and
length-weight relationships; and habitat utilization.
Physico-chemical Water Quality Conditions
Pronounced dissolved oxygen (D.O.) and thermal stratification
existed from March through October (Fig. 4). devoid of D.O. in June at 15 meters and by August no oxygen was present below 6 meters. Total alkalinity stratified primarily between August and October with little or no stratification during the rest of the year (Fig. 5). Stratification of pH began in March and followed essen tially the same pattern as the thermal stratification (Fig. 5). Light penetration was deepest from November through April and varied from 2.1 to 2.4 meters (Fig. 6). The depth of the photic zone began decreasing in May and reached a minimum of 0.9 meters in August. Lake levels decreased from a high of -0.3 meters below spillway level in November to a low of -1.7 meters in July (Fig. 6). A slight rise in lake level occurred in August and September to -1.5 meters but decreased back to -1.7 meters in October. 12 gure 4. nhy emper ur n oxgn . s n r e t t a p n o i t a c i f i t a r t s xygen o and re tu ra e p m te onthly M . 4 e r u ig F DEPTH (meters) at e = ( = re tu ra e p m e T XGN (ppm) OXYGEN EPRTR C) e ( TEMPERATURE oye = —• . ) •— — ( = oxygen , ) 5 30 15 June 22 June Mar.30 Dec. 3 Dec. a. 28 Jan. c. 12 Oct. 13 gure 5. nhy H n total alkalinity stratification patterns. s n r e t t a p n o i t a c i f i t a r t s y t i n i l a k l a l a t o t and pH onthly M . 5 e r u ig F DEPTH (met H ( = pH Nov. 5 Nov. total alkalinity = —•— ). ) — • — ( = y t i n i l a k l a l a t o t , ) OA ALKALINITY (ppm) TOTAL et 14 Sept. 0 110 90 Oct.12 Jan.28 14 15 LAKE LEVEL ( m e t e r s ) 71 72 Figure 6. Annual Secchi disk and lake level fluctuation patterns. Secchi disk = C ------) , la k e l e v e l = (— •— ) . 16 Reproductive Potential Female bass outnumbered male bass by a ratio of 52.1% (203) to 47.9% (187), respectively. This ratio did not differ significantly from a 1:1 ratio according to the chi-square test (Steel and Torrie 1960). Among the females, sexual m aturity was attained between the second and third year of life. Two-year-old bass contained immature, developing, and mature ovaries while all three-year-old and older bass were mature. Length and weight comparisons indicated that the immature two-year-old bass was shorter and weighed less than the mature two-year old bass (Table 1). A total of 11 females ranging in S.L. from 22.2 to 31.1 cm showed fecundities varying from 15,000 to 69,000 eggs (Appendix B). Spaw ning The principal spawning sites of the bass were coves at the north and southeast areas of the lake although a few scattered nests occurred elsewhere (Fig. 7). These areas were characterized by shal low water, a level or gradually sloping bottom, and an abundant growth of submerged aquatic vegetation. The lake bottom substrate was com posed of mud, silt, and detritus with an underlying strata of sand, gravel, and rocks. Bass first began their spawning activity on March 31 when the O inshore water temperatures reached 14.4 C. Peak spawning occurred one week later when 14 bass, presumably males, were observed guarding nests. The water temperature was then 17.7 C. On April 14, the water O temperature decreased to 14.6 C and while 12 nests were observed, only 17 Table 1. Sexual maturity stages of bass collected from March -May 1972. Sam ple Mean S. L. Mean weight Y ear c l a s s M aturity stage s iz e (cm) (g ) 1971 10 9 .0 2 4 .2 Im m ature 1970 1 1 4 .9 8 4 .7 Im m ature 1970 2 1 9 .9 2 2 9 .1 D e v e lo p in g 1970 1 2 2 .2 3 1 5 .6 M a tu re 1969 2 2 6 .6 5 6 9 .0 M atu re S tu n te d 13 2 9 .0 7 9 0 .3 M atu re 18 Spillway Figure 7. Bass spawning areas. 19 three were guarded. The guarded nests contained viable eggs while the abandoned nests contained white opaque eggs covered with fungus. From O April 22 to June 14, water temperatures rose steadily to 25.2 C, but the number of guarded nests observed on five separate occasions remained between two and five. All of these nests contained either viable em bryos or no eggs. A sample of 15 bass nests showed that the nests were located at water depths ranging from 50 to 150 cm with a mean of 92 cm. Most nests were excavated into the lake bottom to depths varying from 1.5 to 13 cm with a mean depth of 6.5 cm among dense beds of Myriophyllum. The majority of nests had clean bottoms composed of sand and gravel with a few small rocks lying toward the middle. One nest was found on top of a flat boulder. Eggs collected from nests adhered to the nest substrate. Egg size from 50 samples averaged 1.5 mm in diameter with a range of 1.4 to 1.6 mm. Viable eggs were clear, light yellow in color and contained a prominent yellow oil spot. Eggs collected from one nest on April 14 were in two stages of development. One stage was undeveloped while the other stage had fish- • like structures. Observations of Fry and Fingerlings Schools of bass fry were observed between June 1 and June 22. The schools were generally located in either the northern or southern areas of the lake 20 The results of sampling six schools showed fry varying in S.L. from 1.1 to 3.3 cm. Visual estimates of the numbers of fry per school ranged from 40 to 5000. Individual schools showing the smallest and largest mean lengths also contained the fewest estimated numbers of fry while schools with mean lengths intermediate between the two extremes contained the most estimated numbers of fry. Samples from these schools were easily obtained by dip-netting. However, when sufficiently disturbed (i.e ., by agitating the water with the outboard motor), the schools would scatter into the aquatic vegetation and remain there un til the disturbance had ended. They would then reappear in small groups and resume their schooling in open water. Solitary bass fry were first sighted on June 14. The smallest fry caught measured 2.2 cm S.L. although, in general, these fry were larger than the schooling fry. Solitary fry and fingerlings could not be caught by dip-netting although seining within the aquatic weeds proved successful. These fish appeared extremely wary and with the slightest disturbance (i.e ., hand movement by the observer) they would retreat into the Myriophyllum. Available Fish Forage Invertebrates A wide variety of benthic invertebrates was present, but a de crease in variety occurred with increased depth (Table 2). There were 12 invertebrate types in the 0.5 to 5.0 meter depth range, 10 in the 5.1 to 10.0 meter range, and only 5 in the 10.1 meter and deeper range. At times, no invertebrates were found in more than 15 meters of water. 21 Table 2. Benthic invertebrate composition at various water depths. Depth Interval (m) Invertebrate classification* 0.5 - 5.0 Class Oligochaeta Order Cladocera Order Podocopa Order Eucopepoda Order Hydracarina Family Baetidae Family Leptoceridae Family Tendipedidae Family Ceratopogonidae Family Culicidae Family Physidae Family Planorbidae 5 .0 - 1 0 .0 Phylum Nematomorpha Class Oligochaeta Order Cladocera Order Podocopa Order Eucopepoda Family Tendipedidae Family Ceratopogonidae Family Culicidae Family Planorbidae Class Pelecypoda 10.0 - 18.0 Phylum Nematomorpha Class Oligochaeta Order Eucopepoda Family Tendipedidae Family Culicidae a. See Appendix A for further clarification. 22 The litto ral weed samples yielded a larger variety of inverte brates than did the benthic samples. There were a total of 23 types collected in litto ral weed samples as compared to 12 in the benthic samples at the same water depth, A seasonal variation in the relative abundance of the litto ral weed invertebrates was observed (Table 3), Monthly counts of crayfish approximately 2,5 cm long or larger showed a minimum in December and a maximum in June (Fig. 8). Numerous crayfish less than 2 cm long were observed in April and May next to shore in water free of Myriophyllum and less than 15 cm deep. In con trast, larger crayfish were seen throughout most of the year on or around rocks and wood debris in deeper water containing Myriophyllum. Food Habits The food habits of bass varied according to fish size and sea son (Tables 4 to 7). Generally, as bass increased in length, their diets progressed from zooplankton to aquatic insects, to fish, and finally to crayfish. As the seasons changed, the bass length, when the dietary transitions occurred, also changed. During the summer, clad- ocerans were the primary food of bass fry up to 2.9 cm S.L. while aquatic insects (i.e ., tendipedids and zygopterans) were the primary foods of bass ranging from 3.0 to 5.9 cm S.L. Largemouth bass fry became the most important food for bass ranging from 6.0 to 14.9 cm and crayfish were the most important food for bass 15.0 cm and larger. However, winter samples showed that cladocerans were the most impor tant food for bass up to 19.9 cm S.L. with bass 20.0 cm and larger con suming prim arily crayfish. 23 Table 3. Littoral weed invertebrate composition and estimated seasonal relative abundance. Invertebrate Relative abundance*3 classification8 Spring Summer F a l l W in te r Family Hydridae CR R A Class Turbellaria C CR C Class Oligochaeta CCR R Order Cladocera A R A A Order Podocopa A AC A Order Eucopepoda CR R A Family Talitridae R N R R Orconectes causeyi R N N N Order Hydracarina R N R N Family Baetidae N RC C Family Aeschnidae NN RN Family Libellulidae R RRN Family Coenagrionidae A CA R Order Hemiptera N RCN Family Hydroptilidae NRCA Family Leptoceridae N N RN Family Psychomyiidae R N N N Order Coleoptera R NNN Family Ceratopogonidae R A R N Family Culicidae N N RN Family Ancylidae A N RA Family Physidae AC RR Family Planorbidae AA AA a. See Appendix A for further clarification. b. A = Abundant, C = Common, R = Rare, and N = Absent. 24 Figure 8. Counts of crayfish 2.5 cm long or larger from three shoreline stations. 25 Table 4. Primary and secondary foods of bass during the spring (M arch - M ay). B ass S. L. F r e q . o f Mean interval Primary food Secondary food o c c u rr e n c e b u lk (cm) (%) in d e x 1 .0 - 1 .9 - - - 2 .0 - 2 .9 - - - 3 .0 - 3 .9 - - - 4 .0 - 4 .9 B a e tid a e 1 0 0 .0 1 .0 Cladocera 100.0 2 .0 5 .0 - 5 .9 C la d o c e ra 6 6 .7 4 .7 Tendipedidae 6 6 .7 5 .3 6 .0 - 6 .9 Z y g o p te ra 6 6 .7 4 .0 C la d o c e ra 6 6 .7 4 .7 Tendipedidae 66.7 4 .7 7 .0 - 7 .9 • C r a y f is h 7 1 .4 3 .7 Tendipedidae 4 2 .9 7 .1 8 .0 - 8 .9 Crayfish 100.0 1.0 9 .0 - 9 .9 Crayfish 100.0 1.5 Insect remains 5 0 .0 5 .5 10.0 - 14.9 Tendipedidae 62.5 5.5 Crayfish 50.0 6.0 15.0 - 19.9 Threadfin shad 3 8 .5 6 .5 Crayfish 30.8 7 .4 20.0 - Crayfish 65.6 4 .2 Fish remains 1 5 .6 8 .6 26 Table 5. Primary and secondary foods of bass during the summer (June - August). Bass S. L. F r e q . o f Mean i n t e r v a l Primary food Secondary food o c c u rr e n c e b u lk (cm) (7.) in d e x 1 .0 - 1 .9 Cladocera 100.0 1.2 E ucopepoda 9 0 .4 2 .8 2.0 - 2.9 Cladocera 94.4 2 .3 Eucopepoda 94.4 2 .4 3 .0 - 3 .9 Tendipedidae 60.0 5 .6 Cladocera 65.0 5 .7 Zygoptera 48.3 5 .7 4 .0 - 4 .9 Z y g o p te ra 6 3 .0 4 .5 Cladocera 59.3 6 .0 B a e tid a e 5 1 .9 6 .0 5 .0 - 5 .9 Zygoptera 75.0 3 .3 B a e tid a e 5 0 .0 6 .0 6 .0 - 6 .9 Largemouth bass 1 0 0 .0 1 .0 7 .0 - 7 .9 Largemouth bass 5 0 .0 5 .5 Insect remains 50.0 5 .5 Hemiptera 50.0 6 .0 8 .0 - 8 .9 Largemouth bass 1 0 0 .0 1 .0 9.0 - 9.0 Largemouth bass 3 7 .5 6 .6 Crayfish 25.0 7 .9 Insect remains 2 5 .0 7 .9 10.0 - 14.9 Largemouth bass 2 9 .4 7 .4 Fish remains 23.5 7 .9 15.0 - 19.9 C r a y f is h 3 3 .3 7 .0 Fish remains 3 3 .3 7 .2 20.0 - Crayfish 5 0 .0 5 .8 Fish remains 3 0 .0 7 .4 27 Table 6. Primary and secondary foods of bass during the fall (September - November). Bass S. L. F r e q . o f Mean i n t e r v a l Primary food Secondary food occurrence b u lk (cm) (%) in d e x 1 .0 - 1 .9 - - - 2.0 - 2.9 Cladocera 1 0 0 .0 1 .0 Baetidae 100.0 1 .0 Tendipedidae 100.0 2 .0 3 .0 - 3 .9 Cladocera 89.5 2 .8 B a e tid a e 5 7 .9 5 .4 4 .0 - 4 .9 C la d o c e ra 8 5 .4 3 .4 E ucopepoda 6 9 .5 5 .1 5 .0 - 5 .9 B a e tid a e 8 1 .0 3 .7 Cladocera 85.7 4.2 6.0 - 6.9 Anisoptera 50.0 5 .5 Eucopepoda 50.0 5 .5 Baetidae 50.0 6 .0 Insect remains 5 0 .0 6 .0 7 .0 - 7 .9 A n is o p te r a 5 0 .0 5 .5 Threadfin shad 5 0 .0 5 .5 Tendipedidae 50.0 6 .0 Insect remains 5 0 .0 6 .0 8 .0 - 8 .9 Insect remains 5 0 .0 5 .5 Threadfin shad 5 0 .0 5 .5 9 .0 - 9 .9 - - - 10.0 - 14.9 Threadfin shad 3 3 .3 7 .1 Largemouth bass 2 2 .2 8 .0 15.0 - 19.9 Threadfin shad 3 8 .5 6 .5 Fish remains 3 0 .8 8 .2 2 0 .0 - C r a y f is h 4 6 .7 5 .8 Fish remains 3 3 .3 7 .1 28 Table 7. Primary and secondary foods of bass during the winter (December - February). Bass S. L. F r e q . o f Mean i n t e r v a l Primary food Secondary food occurrence b u lk (cm) (%) in d e x 1 .0 - 1 .9 - - - 2 .0 - 2 .9 - - - 3 .0 - 3 .9 - - - 4 .0 -4.9 Cladocera 100.0 1 .4 B a e tid a e 3 7 .5 7 .0 5 .0 - 5 .9 C la d o c e ra 1 0 0 .0 1 .8 B a e tid a e 4 2 .1 6 .6 6 .0 - 6 .9 C la d o c e ra 1 0 0 .0 2 .6 Z y g o p te ra 2 8 .6 7 .6 7 .0 - 7 .9 C la d o c e ra 1 0 0 .0 . 1 .5 * B a e tid a e 5 0 .0 5 .8 8 .0 - 8 .9 C la d o c e ra 1 0 0 .0 1 .0 9 .0 - 9 .9 C la d o c e ra 1 0 0 .0 1 .0 10.0 - 14.9 C la d o c e ra 7 7 .8 3 .8 Baetidae 44.4 6 .6 15.0 - 19.9 Cladocera 58.3 6.0 Insect remains 3 3 .3 7 .5 - 2 0 .0 - C r a y f is h 4 5 .5 6 .0 Fish remains 2 7 .3 7 .8 29 Age, Growth, and Length-weight Relationships The results of the aging study showed the presence of large fish which were stunted until 1970 and subsequently resumed good growth, and smaller fish which were never stunted. The previously stunted fish could not be aged confidently because of excessive scale erosion during early life. However, fish which were never stunted could be aged and these composed the year classes 1969-1972. Growth data for 75 previously stunted bass showed good growth during the first year of life because a mean S.L. of 8.6 cm (10.7 cm T. L.) was attained. Stunting began during or after the second year when the fish were 12.6 cm (15.5 cm) long and ended at the beginning or during the 1970 growing season when the bass had reached a length of 14.7 cm (18.0 cm). After the 1970 growing season was completed, the bass had attained 20.6 cm (25.1 cm), an annual growth increment of 5.9 cm (7.1 cm). At the closure of the 1971 growing season, these bass were 27.6 cm (33.5 cm), a growth increment of 7.0 cm (8.4 cm). Annual growth increments appeared to be increasing since the stunting ended. The growth data of 243 bass which never experienced stunting (i.e ., year classes 1969-1971) indicated that these fish reached 6.5 cm S.L. (8.2 cm T.L.) after one year, 16.7 cm (20.4 cm) after two V years, and 23.0 cm (28.0 cm) after three years (Table 8). Maximum growth occurred during the second year of life, after which time the growth rates began to decrease. Incomplete growth rates of young-of-the-year bass (i.e ., 1972 year class) were obtained between July 22 and October 12. Sample sizes 30 Table 8. Calculated growth rates of 1969 - 1971 bass year classes. Number Mean standard lengths (total lengths) in , centimeters at each annulus Y ear c l a s s o r specimens 1 2 3 1971 81 6.1 (7.7) 1970 145 6.0 (7.6) 17.5 (21.4) 1969 17 . 7.4 (9.3) 15.8 (19.4) 23.0 (28.0) Mean 243 6.5 (8.2) 16.7 (20.4) 23.0 (28.0) Mean annual 243 6.5 (8.2) 10.2 (12.2) 6.3 (7.6) in c re m e n t 31 varied from 44 to 78 bass per sampling period. Sampling began on July 22 because spawning was completed and all bass fry schools had dis persed. The growth data indicated that bass fry and fingerlings grew from 3.56 cm to 4.68 cm S.L. during the sampling interval (Fig. 9) or approximately 3.9 mm per month. Growth rates were highest between August and September and lowest between September and October. There were no indications that growth had ceased for the year when sampling was terminated. The length-weight relationship of 439 bass collected during the study was expressed by the logarithmic regression equation (Lagler 1 9 5 6 ), log W = -1.70 + 3.12 log L where W = weight and L = S.L. (Fig. 10). This equation indicates that the present bass population weighs approximately 6.8 g after one grow- ) ing season, 128.4 g after two growing seasons, and 348.4 g after three growing seasons. Habitat U tilization Fry and fingerling bass were always associated with aquatic vegetation. Schooling fry were usually found in open water but within two or three meters of the Myriophyllum while solitary fry and finger- lings were always seen at the periphery or within the vegetation. Adult bass showed a variability in habitat use ranging from shallow, weedy areas to deep, open water. The majority of bass from late spring through fall were observed or caught in open "pockets" JULY 20 AUG. 21 S E P T .14 OCT. 12 Figure 9. Growth rates and size ranges of young-of-the-year bass. 33 MEAN STANDARD LENGTH (CM) Figure 10. Bass length-weight relationship 34 within the Myriophyllum beds located in shallow water, 1.5 meters or less in depth. Next in importance were shallow, open water areas with a rocky bottom and at least some Myriophyllum growing nearby. In this case, the bass were invariably located within 1.5 meters of shore. A third habitat was characterized by deep water, two meters or more in depth, where aquatic vegetation was absent. This habitat was predom inantly utilized in the winter and early spring when shoreline aquatic vegetation was scarce. DISCUSSION The success of the largemouth bass fishery at Parker Canyon Lake may be predicted if future management is based upon the ecologi cal factors affecting the bass life history. This discussion will at tempt to elucidate in detail sane of the most important ecological f a c t o r s . Reproductive Potential and Spawning Success Females reach sexual maturity when either two or three years old and show fecundity variations ranging from 15,000 to 69,000 eggs per female. Obviously all of the eggs do not produce catchable-sized fish. Bennett (1971) states that only a small fraction of the young produced by 100 sexually mature bass in Ridge Lake, Illinois, survived after two years. Most of the m ortality apparently occur during the first few weeks of life when the bass are small and relatively defense l e s s . This study indicates that spawning site availability, length of the spawning season, and nest-tending behavior of the guarding bass were factors which could affect the spawning success. The majority of spawning sites were restricted to two portions of the lake, the northern and the southeastern areas. The necessity of a substrate composed of silt, mud, sand, gravel, or roots for the spawning sites has been reported by Breder (1936), Curtis (1949), 35 36 Kramer and Smith (1962), and many others. These types of substrate were found along most of the lake shoreline and apparently did not con tribute to the observed selectivity. Protective cover as a nesting re quirement has been suggested by some w riters. Bushes on shore and in the water, logs, emergent vegetation, and large rocks or boulders have been described (Hunsaker and Crawford 1964; M iller and Kramer 1971; Swallow, Kelley, and Male 1966). These conditions were only rarely present in the northern and southeastern areas of the lake unless sub merged aquatic vegetation around the nest could be considered protec tive cover. This did not appear to be the reason for the selectivity because Myriophyllum was found along most of the lake shoreline. Fur thermore , on several occasions large areas around the nest Cup to 1.7 meters in diameter) were cleared of Myriophyllum by nesting bass. In addition, Weaver (1971) reported that bass chose nesting sites away from aquatic vegetation at Imperial Reservoir, Arizona. Most of the Parker Canyon Lake bass nests were located on level or gently sloping areas where interm ittent streams entered the lake. The stream run-off had presumably carried large amounts of silt, sand, and gravel into the lake to create the level appearance. Other areas of the lake, in gen eral, had much steeper slopes. Carbine (1939) states that the bottom slope lim ited the depth of bass nests in Deep Lake, Michigan. Bottom slope apparently was more critical in Parker Canyon Lake because the bass appeared to select the level areas and only in rare instances did they attempt nest building in steeper areas. 37 The apparent length of the spawning season was at least 75 days (March 31 to June 14) during which time the mean inshore surface water o o temperature rose from 14.4 to 25.2 C. Initiation of spawning has been reported at temperatures ranging from 14.4 C (M iller and Kramer 1971) to 21.6 C (Breder 1936) with the spawning season lasting for six to ten weeks (Snow 1968a). However the first school of bass fry in this study was not observed until June 1. This suggests that successful spawning did not occur until mid- or late May when surface water temperatures o approximated 20 C. The successful spawning season (about four to five weeks) was obviously shorter than reported in the literature and prob ably affected the bass population by causing a reduction in the 1972 year class strength. The short successful spawning season was associated with a sud den decrease in the surface water temperatures during mid-April. Ob servations made on April 14 showed a large number of deserted nests containing eggs covered with fungus and the water temperature had de- O o creased to 14.6 C from the previous week’s mean of 17.7 C. Kelley (1968) and Jurgens and Brown (1954) stated that a decrease in tempera ture was not the direct cause of egg m ortality. Jurgens and Brown (1954) reported the production of viable embryos at temperatures as low o as 5.6 C. These investigators suggested that death of the eggs was due to the male deserting its nest and, as a result of his action, the eggs were left without aeration and death followed. It appeared that a sim ilar phenomenon occurred at Parker Canyon Lake during this study. 38 The most prominent features of nests observed during the study were that all nests were swept down to sand and gravel by the guarding bass and organic detritus was only rarely found within the nests. The probable significance of a clean, sandy bottom is twofold: (1) a solid substrate to which the adhesive eggs can attach themselves and not be swept away as the guarding bass creates water currents to replenish the oxygen supply and drive off metabolic wastes and (2) a lower oxygen consumption by bacteria decomposing the organic detritus. Factors Affecting Bass Food Habits The food habits of Parker Canyon Lake bass suggest that their diets change as they increase in length. Bass fry feed predominantly upon small organisms such as zooplankton while larger bass feed upon larger organisms such as aquatic insects, fish, and crayfish. Murphy (1949), Rogers (1967), Snow (1971), and many others report sim ilar findings. This feeding behavior may play an "energy economy" role. If a large bass is forced to feed only on zooplankton and small insects, it w ill have to expend much more body energy to satisfy its food re quirements than if a much smaller bass ate sim ilar foods. This expla nation is based on the premise that the larger bass would have to ingest larger numbers of organisms and, hence, do more food-searching. However if the larger bass is able to eat larger organisms, the number of organisms that it must ingest w ill decrease and less body energy is wasted in food-searching. 39 The present study indicates that bass food habits vary season ally and the consumption of some foods may be higher during some sea sons than during others. In the spring, crayfish were most heavily utilized by the bass population. However, during the summer, bass fry became the primary food source for other bass while aquatic insects and threadfin shad became most important in the fa ll. In the winter, cladocerans were the most important food for the entire bass popula tion. Seasonal variations in food habits have been attributed to vari ability in the accessibility and/or abundance of the food organisms or feeding selectivity by the bass (Hodson and Strawn 1968; Kramer and Smith 1962; McCammon, LaFaunce, and Seeley 1964; Snow 1961; Snow 1971). In this study certain insect types, crayfish, and largemouth bass fry occurred most frequently in the bass diets during or just after large numbers were observed, indicating that seasonal food changes were related to abundance of food. Large numbers of other or ganisms (i.e ., ostracods, snails, bluegills, and green sunfish) were observed during certain seasons but were seldom found in bass stomachs, suggesting that they were inaccessible. Bass feed primarily by vision (Bennett 1971) so feeding selectivity may occur by bass being able to observe some forage organisms with greater ease than others. Thus, the seasonal variations in the feeding behavior of bass in Parker Canyon Lake probably results from bass - prey interactions of abundance, acces sibility, and feeding selectivity. 40 Factors Influencing Growth Largemouth bass were introduced surreptitiously into Parker Canyon Lake in the fall of 1965. These fish apparently were mature adults of both sexes because in the spring of 1966 successful spawning occurred and good growth of the fingerlings was noted (Knipe 1966). During 1967-68 while studying the factors affecting the fish forage production in Parker Canyon Lake, Bergersen (1969) noted that bass growth rates had decreased markedly. He found that bass averaging 13.3 cm T.L. in December 1966 had grown only 1.7 cm by the close of the 1967 growing season. With half of the growing season completed in 1968, bass growth was just 0.5 cm. Bergersen attributed the stunted condi tion to insufficient fish forage invertebrate production. He also pointed out that the bass were unable to utilize a great proportion of the benthic invertebrates because of the long period of thermal strati fication that existed in the lake. The stunting at Parker Canyon Lake ended in 1970 and previously stunted bass are now growing well with sane bass reaching total lengths of well over 40.0 cm by October 1972. The Arizona Game and Fish De partment (personal communication, A. Essbach, Chief of Fisheries Manage ment Division, Phoenix, Arizona, October 18, 1972) indicated that cray fish (Orconectes causeyi) were introduced prior to 1969 probably by fishermen with surplus bait. By 1970, the crayfish population appar ently increased sufficiently to comprise a large part of the bass diet. This inference was suggested by the results of stomach analyses con ducted during this study. Table 4 shows that in the spring crayfish 41 were an important food source of bass 7.0 cm S.L. and larger. When summer arrived, bass 15.0 cm S.L. and larger were feeding predominantly upon crayfish (Table 5). Since the bass averaged 14.7 cm S.L. at the time stunting ended, it appears that a crayfish diet was available to these fish during these two seasons. Thus, the initiation of the in creased growth rate is most likely due to the proliferation of crayfish in 1970. Dean (1969) reported that Orconectes causeyi controlled sub merged aquatic vegetation, including Myriophyllum exalbescens. by feed ing upon it. When Bergersen (1969) studied Parker Canyon Lake, he sus pected that a low turnover rate of Myriophyllum was lim iting the trophic contribution of these plants to the invertebrate food chains which, in turn, lim ited their production. With the appearance of the crayfish, the invertebrate population may have been able to channel more energy into its system to insure good production. Thus it is also possible that the stunting ended because more forage invertebrates were available to the bass and may have supplemented the crayfish diet. Young-of-the-year bass growth was not adversely affected during the stunted period. In fact, their growth rates were higher than that experienced by bass fry spawned after the stunting ended. The rapid growth rates may have resulted from excessive intra-year class canni balism by larger young-of-the-year bass during the stunted period and/or an earlier successful spawning season resulting in a longer growing season during the same period. Snow (1968b) reported no can nibalism among fingerlings raised in hatchery ponds if they were 42 regularly fed adequate amounts of food. However, as related earlier, invertebrate fish food production in Parker Canyon Lake during the stunted period was extremely low. Thus, excessive intra-year class cannibalism could have occurred during this period. The possibility that successful spawning occurred earlier in the year during the stunted period was suggested by Knipe (1966) who reported large schools of bass fry in April and May of 1966. In contrast, the first school of bass fry was sighted on June 1 during the present study. Previously stunted bass grew faster in 1971 than in 1970. This phenomenon suggests that the young-of-the-year crayfish outgrew the bass shortly after the 1970 growing season began. According to Lawrence (1957), bass w ill feed upon forage fish if the maximum depth of the fish's body does not greatly exceed the mouth width of the bass. If the same restriction holds true when crayfish is the forage, then the possibility suggested above may have occurred. In 1971, the bass ap- * patently were large enough to utilize the new year class of crayfish for a longer period of time, resulting in the observed growth increases. The unstunted bass population is presently growing at a r a t e equivalent to the overall bass growth rates from various areas of the country (Table 9). This result is also reflected in the length-weight relationship of all bass sampled where b = 3.12. Clugston (1964) in dicates that b varying from 3.03 to 3.19 represents excellent bass con dition and can usually be correlated with good growth. When the food supply is adequate for good growth, the length of the growing season may become growth-limiting. The length of the 43 Table 9. Growth of largemouth bass in P a r k e r Canyon Lake and in other localities. Mean total lengths (cm) attained at end of year TL___ o c__ a1 lityJ 1 2 3 4 3 Montana ponds 4 .8 9 .7 1 4 .5 1 9 .6 Ohio (slow growth) 5 .8 1 3 .2 2 0 .3 2 5 .4 Brown's Lake, Wise. 8 .6 16.8 23.1 28.2 M in n e so ta 8 .9 1 7 .0 2 3 .6 2 9 .2 Whitmore Lake, Mich. - 1 6 .8 2 4 .1 2 9 .7 Lake Vesuvius, Ohio 8 .9 1 7 .8 2 4 .9 2 9 .7 O hio 8 .9 1 7 .8 2 5 .7 3 1 .8 W isc o n sin 8 .4 1 8 .8 2 6 .7 3 1 .8 Connecticut 1 3 .0 2 1 .1 2 7 .2 3 2 .8 Quabbin Reservoir, Mass. 10.2 23.4 32.5 3 8 .1 Lake Wappapello, Mo. 1 3 .7 2 7 .7 3 3 .8 4 0 .9 L o u is ia n a 1 9 .3 2 8 .7 3 6 .8 4 7 .8 Norris Lake, Tenn. 1 7 .5 3 1 .5 3 7 .3 4 0 .9 Mean of all references 1 0 .7 2 0 .0 2 7 .0 3 2 .8 Parker Canyon Lake, 8 .2 2 0 .4 2 8 .0 - Arizona (present study) a. Data compiled from Emig (1966). 44 growing season varies within the same age class as well as between dif ferent age classes. Variations among young-of-the-year bass are ex pected because spawning does not occur at one specific time but is stretched out over several weeks. However, variations in the length of the growing season of yearling or older bass are not expected because they are present in the lake before the growing season begins. Never theless, some of these bass were found with new annuli on scales as early as March while others did not show this until June. Bennett (1954) found that the growing season of bass in Ridge Lake, Illinois, began when water temperatures ranged from 10.1°to 15.7 C. This study O O showed that surface water temperatures ranged from 12.0 to 13.3 C when the growing season began. By this time, the lake had become thermally stratified. Whitmore, Warren, and Doudoroff (1960) reported that bass exhibited some avoidance to oxygen concentrations of 4.5 ppm and avoid ance increased as oxygen decreased. Parker Canyon Lake waters had oxy gen concentrations well over 4.5 ppm until April (Fig. 4). Thus, it was possible that the bass were distributed throughout the water column until this time. While bass spending a considerable time close to the surface could have metabolic rates high enough to stim ulate growth be tween February and March, those deeper down would s till be in water too cool for growth. On May 22, 4.5 ppm of oxygen was found between 8 and o O 9 meters while the temperature ranged from 11.0 to 13.0 C at the same depths. The entire inhabitable water column was then warm enough for bass at any depth to begin growing and this growth was detected in June when all bass sampled contained new annuli on their scales. By 45 using sim ilar criteria, some bass probably stop growing between October and November, and by December all bass have ceased growing for the year. This indicates a growing season extending over a minimum of six months and a maximum of ten months. Importance of the L ittoral Weeds The litto ral weeds appear to provide the most important habitat for bass by serving as the major food producing region of the lake and for protective cover. L ittoral weed samples from Parker Canyon Lake contained a large proportion of the same types of organisms found in the bass stomachs such as zooplankton, amphipods, and aquatic insects. Seine hauls made in the weeds also yielded large numbers of crayfish and potential for age fish. In contrast, the pelagic zone produced mainly threadfin shad and zooplankton while the benthic zone produced prim arily oligochaetes which seldom entered the bass diet. Dendy (1956) also noted the poor utilization of benthos by the bass. The littoral weeds also provide protective cover. As reported previously, fry and fingerlings often swam into the weeds when alarmed. In addition, adult bass guarding nests during the spawning season fre quently retreated into the weeds when disturbed by the observer. Fur thermore bass of all sizes were often captured within or near the littoral weeds during seining, gillnetting, or electrofishing opera tions while gillnet sets made in deep, open water only once yielded a b a s s . 46 Bennett (1971) reported that fish production may be decreased by the presence of rooted aquatic vegetation which bind up nutrient m aterials. This certainly does not appear to be the case in Parker Canyon Lake although, as explained earlier, the crayfish may be the major factor causing the difference. Also, it is possible that the rooted aquatic vegetation is not sufficiently dense to the point where its disadvantages outweight its advantages. There may be a pivotal point where the proper amounts of vegetation and open, water w ill sup port a maximum number of bass, and if this ratio is shifted to either side, detrimental results can occur. > CONCLUSION Parker Canyon Lake has the potential for providing a good largemouth bass fishery because successful natural reproduction and good growth of all age classes are occurring. Adequate forage foods such as aquatic insects and crayfish are available to insure that the good growth w ill continue. Also the bass food chain has been strength ened by the introduction of threadfin shad in May 1971 by the Arizona Game and Fish Department (personal communication, A. Essbach, Chief of Fisheries Management Division, Phoenix, Arizona, October 18, 1972). The shad appeared in large numbers in the fall of 1972. These forage fish should prove beneficial to the bass fishery by providing addi tional food for growth if the shad population remains large. 47 APPENDIX A CLASSIFICATION SCHEME* OF INVERTEBRATES Phylum Coelenterata Class Hydrozoa Order Hydroida Family Hydridae Phylum Platyhelm inthes Class Turbellaria Phylum Nematomorpha Phylum Annelida Class Oligochaeta Phylum Arthropoda Class Crustacea Order Cladocera Order Podocopa Order Eucopepoda Order Amphipoda Family Talitridae Order Decapoda Family Astacidae (Orconectes causeyi) Class Arachnoidea Order Hydracarina Class Insects Order Ephemeroptera Family Baetidae Order Odonata Suborder Anisoptera Family Aeschnidae Family Libellulidae Suborder Zygoptera Family Coenagrionidae Order Hemiptera Order Trichoptera Family Hydroptilidae Family Leptoceridae Family Psychomyiidae Order Coleoptera a. From Pennak (1953). 48 Order Diptera Family Ceratopogonidas Family Culicidae Family Tendipedidae Phylum M ollusca Class Gastropoda Order Pulmonata Family Ancylidae Family Physidae Family Planorbidae Class Pelecypoda APPENDIX B FECUNDITY VARIATIONS IN BASS TAKEN IN MARCH AND APRIL 1972 Ovary weight Y ear c l a s s S. L. (cm) Weight (g) F e c u n d ity (g ) 1970 2 2 .2 3 1 5 .6 17.64 17,000 1969 2 6 .1 5 0 0 .1 9 .7 6 1 5 ,0 0 0 1 9 6 9 . 2 7 .0 637.9 30.27 34,000 S tu n te d 28.4 711.0 32.00 31,000 S tu n te d 2 8 .8 8 2 6 .4 6 5 .6 9 5 9 ,0 0 0 S tu n te d 2 9 .3 8 4 6 .0 5 6 .3 5 6 0 ,0 0 0 S tu n te d 2 9 .7 7 6 1 .6 3 4 .1 2 3 3 ,0 0 0 S tu n te d 2 9 .9 9 2 9 .5 6 6 .9 8 5 5 ,0 0 0 S tu n te d 3 0 .3 8 5 7 .1 4 1 .2 6 4 6 ,0 0 0 S tu n te d 3 0 .8 9 0 0 .8 5 8 .4 5 5 7 ,0 0 0 S tu n te d 3 1 .1 9 5 4 .4 73.43 69,000 50 LIST OF REFERENCES American Public Health Association. 1965. Standard Methods for the Examination of Water and Wastewater Including Bottom Sedi ments and Sludges. Amer. Public Health Assoc., Inc., New York, 769 p p . Bagenal, T. B., and Erich Braum. 1968. Eggs and early life history. In Ricker. W. E. (ed.). Methods for Assessment of Fish Produc tion in Freshwaters. Int. Biol. Programme. Handb. No. 3, pp. 1 5 9 -1 8 1 . Bennett, George W. 1948. The bass-bluegill combination in a small artificial lake. Bull. 111. Nat. Hist. Survey 24(3):377-4l2. ______. 1954. Largemouth bass in Ridge Lake, Coles County, Illinois Bull. 111. Nat. Hist. Survey 26(2):217-276. ______. 1971. Management of Lakes and Ponds. Van Nostrand Reinhold C o ., New Y ork, 375 p p . Bergersen, Eric P. 1969. Some factors affecting fish forage production in four Arizona lakes. M. S. Thesis, The Univ. of Arizona, Tucson, 89 p p . Breder, C. M., Jr. 1936. The reproductive habits of the North American sunfishes (family Centrarchidae). Zool. 21(1):1-48. Carbine, W. F. 1939. Observations of the spawning habits on centrar- chid fishes in Deep Lake, Oakland County, Michigan. Prog. Fish Cult. 44:33-34. Clugston, James P. 1964. Growth of the Florida largemouth bass, Micropterus salmoides floridanus (Le Sueur), and the northern largemouth bass, M. s. salmoides (Lacedepe), in subtropical Florida. Trans. Am. Fish. Soc. 93(2):146-154. Curtis, Brian. 1949. The warm-water game fishes of California. Calif. F is h and Game 3 5 ( 4 ):2 5 5 -2 7 4 . Dean, Jack L. 1969. Biology of the crayfish Orconectes causeyi and its use for control of aquatic weeds in trout lakes. U. S. Bur. Sport Fish, and W ildlife Tech. Paper 24, 15 pp. Dendy, Jack L. 1956. Bottom fauna in ponds with largemouth bass only and with a combination of largemouth bass plus bluegill. J. Tenn. Acad. Sci. 31(3):198-207. 51 52 Eddy, Samuel. 1969. How to Know the Freshwater Fishes. Wm. G. Brown Co. Publ., Dubuque, Iowa, 286 pp. Bnig, John W. 1966. Largemouth bass. In Calhoun. Alex (ed.). In land Fisheries Management. Calif. Dept, of Fish and Game, Sacra mento, California, pp. 332-353. Hodson, Ronald G., and Kirk Strawn. 1968. Food of young-of-the-year largemouth and spotted bass during the filling of Beaver reser voir, Arkansas. Proc. Ann. Conf. S. E. Assoc. Game and Fish Comm. 22:510-516. Hunsaker, Don, II, and R. W. Crawford. 1964. Preferential spawning behavior of the largemouth bass, Micropterus salmoides. Copeia 1 :2 4 0 -2 4 1 . Jurgens, Kenneth C., and William H. Brown. 1954. Chilling the eggs' of the largemouth bass. Prog. Fish-Cult. 16(4):172-175. Kelley, John W. 1962. Sexual maturity and fecundity of the largemouth bass, Micropterus salmoides (Lacedepe), in Maine. Trans. Am. Fish. Soc. 91(1):23-28. ______. 1968. Effects of incubation temperature on survival of largemouth bass eggs. Prog. Fish-Cult. 30(3):159-163. Knipe, Ted. 1966. Fishery investigations in region VI, periodic sur vey of waters. Completion Report, Ariz. Game and Fish Dept., Project F-7-R-9, 7 pp. Kramer, Robert H., and Lloyd L. Smith, Jr. 1962. Formation of year classes in largemouth bass. Trans. Am. Fish. Soc. 91(l):29- 4 1 . Lagler, Karl F. 1956. Freshwater Fishery Biology, Wm. C. Brown Co., Dubuque, Iowa, 421 pp. Lawrence, J. M. 1957. Estimated sizes of various forage fishes large mouth bass can swallow. Proc. Ann. Conf. S. E. Assoc. Game and Fish Comm. 11:220-225. McCammon, G. W., D. LaFaunce, and C. M. Seeley. 1964. Observations on the food of fingerling largemouth bass in Clear Lake, Lake County, California. Calif. Fish and Game 50(3):158-169. M iller, Edward E. 1966. Age and growth determinations. In_Calhoun, Alex (ed.). Inland Fisheries Management. Calif. Dept, of Fish and Game, Sacramento, California, pp. 57-69. 53 M iller, Kent D., and Robert H. Kramer. 1971. Spawning and early life history of largemouth bass (Micropterus salmoides) in Lake Pow ell. In_ Hall, G. E. (ed.). Reservoir Fisheries and Limnology, Am. Fish. Soc. Special Public. No. 8, pp. 73-83. Murphy, G. I. 1949. The food of young largemouth black bass (Microp terus salmoides) in Clear Lake, California. Calif. Fish and Game 35(3):159-163. Pennak, Robert W. 1953. Fresh-water Invertebrates of the United States. Ronald Press Co., New York, 769 pp. Rainwater, F. H., and L. L. Thatcher. 1960. Methods for collection and analysis of water samples. Geological Survey Water-Supply Paper 1454, U. S. Govt. Print. O ff., Washington, D.C., 301 pp. Rogers, W. A. 1967. Food habits of young largemouth bass (Micropterus salmoides) in hatchery pools. Proc. Ann. Conf. S. E. Assoc. Game and Fish Comm. 21:543-553. Snow, H. E. 1971. Harvest and feeding habits of largemouth bass in Murphy flowage, Wisconsin. Wise. Dept. Nat. Resources Tech. Bull. 50, 25 pp. Snow, J. R. 1961. Forage fish preference and growth rate of large mouth black bass fingerlings under experimental conditions. Proc. Ann. Conf. S. E. Assoc. Game and Fish Comm. 15:303-313. ______. 1968a. Some progress in the controlled culture of the largemouth bass, Micropterus salmoides (Lac.). Proc. Ann. Conf. S. E. Assoc. Game and Fish Comm. 22:380-387. ______. 1968b. Production of six- to eight-inch largemouth bass for special purposes. Prog. Fish-Cult. 30(3):144-152. Steel, Robert G. D., and James H. Torrie. 1960. Principles and Pro cedures of S tatistics. McGraw-Hill Book Co., Inc., New York, 481 p p . Swallow, William H., John W. Kelley, and Larry M. Male. 1966. Inves tigations of first-year mortality in largemouth bass. Final Re port, Contract No. 14-16-0008-725, New York Coop. Fish. Unit, Mimeo., 25 pp. Tesch, F. W. 1968. Age and growth. jtn_ Ricker, W. E. (ed.). Methods for Assessment of Fish Production in Fresh Waters. Int. Biol. Programme. Handb. No. 3, pp. 93-123. Usinger, Robert L. (ed.). 1956. Aquatic Insects of California. Univ. Calif. Press, Berkeley and Los Angeles, 508 pp. 54 Weaver, Ronald Otto. 1971. Ecology of juvenile fish in Imperial res ervoir. M. S. Thesis, The Univ. of Arizona, Tucson, 33 pp. Whitmore, Cecil M., Charles E. Warren, and Peter Doudoroff. 1960. Avoidance reactions of salmonid and centrarchid fishes to low oxygen concentrations. Trans. Am. Fish. Sob. 89(1):17-26. 83