EPA-600/3-77-075
June 1971
Ecological Research Series
EFFECTS OF TEMPERATURE ON HATCHING
SUCCESS AND SURVIVAL OF LARVAE
IN THE WHITE BASS
Environmental Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Duluth, Minnesota 55804
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S. Environmental
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vironmental technology. Elimination of traditional grouping was consciously
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The nine series are:
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This document is available to the public through the National Technical Informa-
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EPA-600/3-77-075
June 1977
EFFECTS OF TEMPERATURE ON HATCHING
SUCCESS AND SURVIVAL OF LARVAE IN THE WHITE BASS
by
J. Howard McConnick
Environmental Research Laboratory-Duluth
Duluth, Minnesota 55804
ENVIRONMENTAL RESEARCH LABORATORY-DULUTH
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
DULUTH, MINNESOTA 55804
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DISCLAIMER
This report has been reviewed by the Environmental Research Laboratory-
Duluth, U.S. Environmental Protection Agency, and approved for publication.
Mention of trade names or commercial products does not constitute endorsement
or recommendation for use.
11
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FOREWORD
Our nation's fresh waters are vital for all animals and plants, yet our
diverse uses of water for recreation, food, energy, transportation, and
industry physically and chemically alter lakes, rivers, and streams. Such
alterations threaten terrestrial organisms, as well as those living in water.
The Environmental Research Laboratory in Duluth, Minnesota, develops methods,
conducts laboratory and field studies, and extrapolates findings
—to determine how physical and chemical pollution affects aquatic life
—to assess the effects of ecosystems on pollutants
—to predict effects of pollutants on large lakes through use of models
—to measure bioaccumulation of pollutants in aquatic organisms that are
consumed by other animals, including man.
This report provides data relative to the thermal limits and best
temperatures for successful survival of embryos and larvae of an important
freshwater sport and commercial fish, the white bass (Morone chrysops).
Donald I. Mount, Ph.D.
Director
Environmental Research Laboratory
Duluth, Minnesota
ill
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ABSTRACT
To determine temperature effects on hatching success of white bass
(Morone chrysops) embryos, sample lots of fertilized eggs were exposed to 10
constant temperatures, 6° through 30° C. Exposures were begun at two stages
of embryonic development, before gastrulation and after closure of the
blastopore. Embryos exposed before gastrulation were more sensitive to
extreme temperatures than those exposed after closure of the blastopore.
The percentage of normal larvae hatched from embryos exposed before gastru-
lation was not significantly impaired over the temperature range 18 - 26° C
(P>0.05). When first exposed after blastopore closure the range of
temperatures allowing unimpaired hatching was extended to 14° - 26° C
(P>0.05). Normal larvae hatched at 14 - 28° C from embryos exposed before
gastrulation and at 10 - 28° C when exposed after blastopore closure, but at
the extremes in significantly reduced numbers (P<0.05). Hatching took place
4.5 days after fertilization when incubated at 14° C and 1 day after
fertilization at 26° C.
The 24-hr TL50 for white bass larvae exposed within 24 hr of hatching
and acclimated at temperatures from 14° to 26° C was between 30° and 32° C
and was not altered by acclimation.
iv
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CONTENTS
Foreword ...................... ..........
Abstract ................................ lv
Acknowledgments ............................ v^
1. Introduction
2. Conclusions
3. Recommendations
4. Materials and Methods
5. Results
6. Discussion
References
11
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ACKNOWLEDGMENTS
I thank Mr. D. D. Johnson and Miss C. A. Church for their assistance in
conducting these tests, Mr. B. W. Hawkinson of the Minnesota Department of
Natural Resources and his staff for their cooperation in providing the white
bass brood stock, and Mr. J. N. Dryer for his assistance in calculating
larval TL50 values,
vi
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SECTION 1
INTRODUCTION
Thermal requirements for fishes are dependent on a number of variables,
among which are the species and the life stage being considered (Badenhuizen,
1968). This is a report of the response of three early life stages of the
white bass (Morone chrysops) to a range of constant temperatures.
The life stages studied were embryos before gastrulation, embryos after
closure of the blastopore, and newly hatched larvae (<24 hr old). These
stages are of particular importance since their success is critical to the
establishment of the year-class strength of the species and because once
deposited they are unable to avoid areas of altered temperatures.
The determination of thermal requirements for the well-being of this
species is of particular interest because of its importance both as a sport
and commercial fish (Howell, 1945; Ruelle, 1971; Scott and Grossman, 1973;
Great Lakes Commission, 1974), and because it inhabits large bodies of fresh
water where, through the activities of steam electric generation, perturbation
of natural thermal regimes is most likely to occur. Previous studies of
thermal requirements of this species have been limited or too general to
determine thermal limits for survival or degrees of success at various
temperatures (Yellayi and Kilambi, 1969).
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SECTION 2
CONCLUSIONS
Thermally unimpaired hatching of white bass embryos occurred when the
embryos were exposed from before gastrulation until hatching to temperatures
from 18° to 26° C. Hatching took place at 14° and 28° C, but with reduced
success. After closure of the blastopore, embryos are more tolerant, and
hatching was unimpaired from 14° to 26* C. At 28° C slightly reduced numbers
of normal larvae were produced (P<0.05). Hatching took place 4.5 days after
fertilization at 14° C and 1 day after fertilization at 26° C. The 24-hr
TL50 of 1-day-old larval white bass lies between 30° and 32° C.
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SECTION 3
RECOMMENDATIONS
If white bass reproduction is to be successful, temperatures in the
spawning area during the spawning period and the week after spawning should
be above 14° C and below 28° C. For greater potential year-class strength,
temperatures between 18° and 26° C are preferable, particularly during the
first day or two of incubation. Following hatching, temperatures below 30°
are required to prevent thermally-induced deaths of newly hatched larvae.
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SECTION 4
MATERIALS AND METHODS
On June 7, 1974, sexually mature white bass were brought to the Environ-
mental Research Laboratory at Duluth, Minnesota, The fish were collected
during the preceding 1 or 2 days from spawning populations in Sturgeon Lake,
a backwater area of the Mississippi River near Red Wing, Minnesota. Water
temperatures in the collection area during and immediately preceding netting
were about 16 - 20° C. The fish were held at 16° C until June 8, when the
temperature was raised to 19° C. At this time the females used as the egg
source were each injected intraperitoneally with 1 mg of dried triturated carp
pituitary, in 1 ml of Cortland physiological saline solution (Sneed and
Clemens, 1960). The next day eggs were obtainable from only one female.
These were fertilized with the milt from two males by using the dry method
(Davis, 1956), and the resulting embryos were used as the test specimens.
Duplicate lots of 50 embryos each were exposed to test temperatures.
Exposures were initiated at two stages to determine whether embryonic stage
at first exposure to test temperatures had any effect on thermal tolerance
(Kelly, 1968; Frank, 1974). Initial exposures to test temperatures (6 - 28°
C) were completed in exposure group I by the 32-cell stage, Oppenheimer
stage 7 (Rugh, 1962), before gastrulation. Embryos in exposure group II were
held at 18° C for exposure after closure of the blastopore between Oppenheimer
stages 17 and 18. Exposure group II was "screened" to remove infertile and
dead eggs before sampling and distribution to test temperatures (6 - 30° C).
The range of tested temperatures was expanded for exposure group II to
insure sufficiently high temperatures to exceed the upper lethal limit, and
to allow for possible higher tolerance of more advanced embryos. Increased
range was indicated by the failure to achieve 100% mortality at the upper
limit in group I exposures.
Periodically the eggs were inspected to determine stage of development
and to remove and record dead eggs and embryos for fungus control. As
hatching approached the eggs were inspected daily, and the dead embryos and
infertile eggs were removed and counted. The larvae were segregated and
counted as dead or deformed, or both and "normal" larvae categories. All
live larvae not obviously deformed when examined under 30x magnification
were considered normal larvae. Time to hatching was assessed to the nearest
one-half day in which 50% or more of the larvae hatched.
The embryos were exposed to test temperatures in 4- x 4-cm glass "jars"
whose bottoms were replaced with 0.23-mm opening stainless steel screen. The
"jars" were supported on 13-mm glass legs that held the screens off the
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bottoms of the water baths to allow free movement of water past the embryos.
The water baths were 10 x 40 x 10 cm deep and received a continuous mean flow
of 215 (200-250) ml/mln of Lake Superior water at constant temperatures. At
the drain end of each water bath a self-starting siphon provided an oscilla-
ting water depth. These depth changes provided a flow-through condition
about the embryos of 4.5 - 5.9 cm/min velocity during the draw-down portion
of the cycle and a 0.4 - 0.5 cm/min velocity during the up-welling portion.
The ratio of draw-down time to up-welling time was approximately 1 to 9.
Water temperatures were controlled by a thermostatically controlled
Immersion heater system and monitored by a Honeywell Multipoint recording
telethermometer. Recorder values were daily verified by thermometer readings
in each water bath. Thermometers used in verification were standardized
within +0.1° C of a calibration thermometer certified by the American Society
for Testing and Materials. Mean test temperatures and ranges are reported
in Table 1. Lake Superior water drawn directly from the lake had the
following chemical characteristics: total hardness, 43 - 47 mg/1.; total
alkalinity, 42 - 43 mg/1.; and pH 7.1 - 7.3. Dissolved oxygen concentrations
within the exposure chambers were 7 ppm or greater and the upper limit was
controlled to 104% saturation or lower by air-bubble stripping before delivery
to the exposure water baths. Other chemical characteristics of the test water
were essentially unchanged from those reported by Biesinger and Christensen
(1972). Lighting was by Duro-Test Vita-Lite fluorescent lamps with the
photoperiod normal for the time of year at Duluth, Minnesota.
The results are reported as the percentage of eggs producing normal
larvae. Dead or deformed larvae or both were not considered for analysis
as they were not believed likely contributors to year-class recruitment
(Volodin, 1960; Kokurewicz, 1969). The percentage normal hatch data were
converted to arcsin percentage and analyzed by one-way analysis of variance.
Tukey's multiple range tests were used to identify treatment effects
statistically significant at the 95% level (Steel and Torrie, 1960).
The 24-hr high temperature TL50 values of newly hatched larvae were
determined for larvae from embryos incubated at 14°, 18°, 20°, and 26° C.
The upper tolerance limits were determined in the same water-bath system
used for the embryo studies. Lots of 10 larvae each were tested at 26°,
28°, 30°, 32°, and 34° C. The data were analyzed by probit analysis (Finney,
1964) to derive the TL50 values and the 95% confidence limits.
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SECTION 5
RESULTS
Among group I embryos the maximum mean percentage normal larvae pro-
duced (59%) was from embryos Incubated at 26° C. Those exposed at 18 - 26°
C produced normal larvae at percentages not significantly less than those
at 26° C (P>0.05) (Table 1). Normal larvae were hatched at 14° and 28° C,
but in significantly reduced numbers (P<0.05).
Among group II embryos the maximum mean percentage of normal larvae
(87%) was produced at 18° C. The percentages of normal larvae produced at
temperatures from 14° to 26° C were not significantly less than those at 18e
C (P>0.05) (Table 1). Normal larvae were hatched at 10° and 28° C, but in
significantly reduced numbers (P<0.05).
At 14° C approximately 4.5 days were required after fertilization for
hatching, but only 1 day was required at 26° C. Rates of development in-
creased directly with temperature. Tolerance of newly hatched larvae did
not change with acclimation. Larvae acclimated at 14°, 18°, 20°, and 26° C
all had 24-hr TLSO's near 31° C; overlapping 95% confidence limits ranged
from 28.9° C to nearly 33.6° C (Table 2).
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TABLE 1
PERCENTAGE NORMAL HATCH OF WHITE BASS EMBRYOS EXPOSED TO CONSTANT TEMPERATURES.
MEAN PERCENTAGE HATCHES UNDERSCORED BY CONTINUOUS DOTTED LINES ARE NOT SIGNIFICANTLY
DIFFERENT FROM THE MAXIMUM MEAN PERCENTAGE HATCH (P<0.05)3
. . . , . — ' — • — •
Exposure Group (embryonic stage)
Group I (before gastrulation)
Mean temperature (°C)
Range (°C)
Replicate A
Replicate B
Mean A and B
6 10 14
5.8 9.8 14.2
5.4-6.5 9.0-11.0 13.3-14.8
0 Ob 28
0 Ob 24
0 0 26
Nominal Temperature ( C)
18 20 22 24 26 28 30
18.0 20.1 21.8 23.7 2j.'J 2C.O
17.8-18.2 19.8-20.5 21.4-22.0 23.3-23.8 25.7-26.1 27.7-28.1
34 38 66 30 56 28
30 48 50 32 62 18
32 43 53 31 59 23
Group II (after closure of the blastopore)
Mean temperature (°C)
Range (°C)
Replicate A
Replicate B
Mean A and B
6.0 10.0 14.2
5.4-6.5 9.2-11.0 13.3-14.8
0 34 76
0 22 72
0 28 74
18.0 20.1 21.8 23.6 26.1 27.9 30.2
17.8-18.2 10.8-20.5 21.4-22.0 23. 3-23. t 25.7-26.3 27.5-28.2 30.0-30.5
84 78 66 78 58C 50 0
90 74 73 84 74 58 0
87 76 72 81 66 54 0
"When in the transformed form for statistical testing. Tukey's honestly siBnificant difference for the before-gastrulation results was 16.4%
(P=0.05), for the after-closure-of-the-blastopore data it was 20.2% (P=0.05). All data here are presented as before normalization and
transformation.
bExposed first 14 hr to mean of 9.2° C, thence to 10.0° C until hatching.
cProbably was higher as container holding embryos was found tipped during part of the day of hatching allowing possible escape of swimming
larvae without recapture for counting.
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TABLE 2
a
TWENTY-FOUR-HR TL50'S OF NEWLY HATCHED LARVAL WHITE BASS.
(ACCLIMATION TEMPERATURES ARE INCUBATION TEMPERATURES).
oo
TL50
Acclimation temperature ( C)
• - - — ~
14
18
14-26 Combined
Test Dead
m
34.2
32.3
30.1
28.2
26.2
100
40
100b
10
0
34.4
32.3
30.3
28.0
26.4
100
100
10
0
0
34.
32.
30.
28.
26.
4
3
3
0
4
100
40
20
0
0
34
32
30
28
26
.2
.3
.3
.0
. 4
100
70
20
30
90b
34.4
32.3
30.3
28.0
26.3
100
62
17
10
0
31.7
30. £
32.0
30.6
31.3
95% C.L.
30.1-33.0
31.1-33.0
29.0-31.9
28.9-33.6
aN - 10, all test groups.
bPoints arbitrarily considered aberrant, listed for completeness of data but not used in analysis.
Graphic method with logarithmic probability paper; two values between 0 and 100% effect required for Finney's (1964) nethod not available.
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SECTION 6
DISCUSSION
Hatching success in group I was uninhibited from 18° to 26° C. These
limits extend well beyond the 15.6 - 16.7° C optimum limits previously
reported by Yellayi and Kilambi (1969). Their suggested upper lethal limit,
20.0° C, was also found too restricted; normal larvae in this study were
produced through 28° C, though with reduced success at the upper temperature.
Yellayi and Kilambi's (1969) lower lethal limit, 12.8, seems a reasonable
estimate of expected 100% mortality based on the downward trend between 18°
and 10° C in the data reported here.
The overall higher percentages of successful hatching at temperatures
between 18° and 26° C among group II embryos than among group I embryos are
not considered a function of the stage of development when first exposed.
They are rather the result of the "screening" for live embryos that was
carried out before sampling the test lots of the more advanced embryos. Thus
more fertilized eggs are represented in group II samples, and higher percen-
tage hatching would be expected.
The 24-hr TL50 values determined for 1-day-old white bass were not
changed over the range of acclimations from 14° to 26° C. Acclimation has
generally been accepted as a mechanism by which fish are able to adjust their
thermal tolerance. However, the early larval stage is apparently unable to
accomplish the necessary physiological changes. This result is consistent
with previously reported responses among 1-day-old brook trout (McCormick
e£ al., 1972). McCauley (1963) suggests that the capacity for an organism
to adjust to temperature changes probably requires functional organ systems
not present in early embryonic forms.
The life stage of the organism is important in determining its responses
to environmental temperatures, as illustrated by the lack of reduction in
hatching success with increase in temperature range when embryos are first
exposed after closure of the blastopore rather than before. These results
also corroborate Badenhuizen's (1968) finding with largemouth bass that cold
tolerance is gained more with increased age of the embryo than is heat
tolerance. Thermal requirements determined in the laboratory correlated
well with naturally occurring environmental requirements. In this case, the
lower limits for successful incubation, >10° and _<_ 14° C determined in this
laboratory study, are close to the lower thermal threshold initiating
spawning, 11.7° - 14.4° C (Webb and Moss, 1967), suggesting that natural
selection sets the temperature at which the spawning act occurs.
,9
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Webb and Moss (1967) report observations of spawning In natural waters
up to 23.9° C, somewhat cooler than the 26° C found in this study to permit
uninhibited hatching success, but allowing for seasonal rising temperature
trends during the time required before hatching, not an unreasonable value.
Recognizing that field observations may misinterpret ripe-fish activity for
spawning and fail to observe the remaining few late spawners after the
preceding masses have departed the spawning area, field and laboratory values
are probably even closer.
10
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REFERENCES
Badenhuizen, T. R. 1968. Effects of incubation temperature on survival of
largemouth bass embryos. 1967 Ann. Research Dept. Rep., New York, Coop.
Fish. Unit, Cornell Univ., Ithaca, N.Y. p. 16-32.
Biesinger, K. E., and G. M. Christensen. 1972. Effects of various metals
on survival, growth, reproduction, and metabolism of Daphnia magna. J. Fish
Res. Board Can. 29:1691-1700.
Davis, H. S. 1956. Culture and diseases of game fishes. 2nd ed. Univ.
California Press, Berkeley, Calif. 332 p.
Finney, D. J. 1964. Statistical method in biological assay. 2nd ed.
Hafner Publ. Co., New York. 668 p.
Frank, M. L. 1974. Relative sensitivity of different developmental stages
of carp eggs to thermal shock, p. 171-176. In J. W. Gibbons and R. R.
Sharitz (ed.). Thermal ecology. Technical Information Center, U. S. Atomic
Energy Commission.
Howell, H. H. 1945. The white bass in TVA waters. Tennessee Acad. Sci.
20:41-48.
Kelly, J. W. 1968. Effects of incubation temperature on survival of large-
mouth bass eggs. Prog. Fish-Cult. 30:159-163.
Kokurewicz, B. 1969. The influence of temperature on the embryonic
development of the perches: Perca fluvjatilis L. and Lucioperca L.
Zoological Pol. 19:47-67.
McCauley, R. W. 1963. Lethal temperatures of the developmental stages of
the sea lamprey Fetromyzon marinus L. J. Fish. Res. Board Can. 20:483-490.
McCormick, J. H., K. E. F. Hokanson, and B. R. Jones. 1972. Effects of
temperature on growth and survival of young brook trout, Salvelinus
fontinalis. J. Fish Res. Board Can. 29:1107-1112.
Ruelle, R. 1971. Factors influencing growth of white bass in Lewis and Clark
Lake, p. 411-423. JEn G. E. Hall (ed.) Reservoir fisheries and limnology.
Amer. Fish. Soc., Spec. Pub. No. 8.
Rugh, R. 1962. Experimental embryology; techniques and procedures, 3rd ed.
Burgess Publishing Co., Minneapolis, Minn. 501 p.
11
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Scott, W. B., and E. J. Grossman. 1973, Freshwater fishes of Canada. Fish.
Res. Board Can., Bull. 184. 966 p.
Sneed, K. E., and H. P. Clemens. 1960. Use of fish pituitaries to induce
spawning in channel catfish. U.S. Fish Wildl. Serv. Spec. Sci. Rept., Fish.
No. 329. 12 p.
Steel, R. G. D., and J. H. Torrie. 1960. Principles and procedures of
statistics. McGraw-Hill Book Co., New York. 481 p.
Great Lakes Comm. 1974. Great Lakes Newsletter. Great Lakes Comm., Ann
Arbor, Mich. May-June. 18:5.
Volodin, V. M. 1960. Effect of temperature on the embryonic development of
the pike, the blue bream (Abramis ballerus L.) and the white bream (Blicca
bjoerkna L.). Trudy Inst. Biologii Vodokhranilishch 3:231-237.
Webb, J. F., and D. D. Moss. 1967. Spawning behavior and age and growth of
white bass in Center Hill Reservoir, Tennessee. Proc. S. E. Assoc. Game
Fish. Comm., 21:343-357.
Yellayi, R. R,, and R. V. Kilambi. 1969. Observations on early development
of white bass, Roccus chrysops (Rafinesque). Proc. S. E. Assoc. Game Fish.
Comm. 23:261-265.
12
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TECHNICAL REPORT DATA
' (Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA-600/3-77-075
4. TITLE ANDSUBTITLE
EFFECTS OF TEMPERATURE ON HATCHING SUCCESS AND
SURVIVAL OF LARVAE IN THE WHITE BASS
3. RECIPIENT'S ACCESSI Of* NO.
5. REPORT DATE
June 1977 issuing date
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
J. Howard McCormick
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Environmental Research Laboratory - Duluth, MN
Office of Research and Development
U.S. Environmental Protection Agency
Duluth, Minnesota 55804
1O. PROGRAM ELEMENT NO.
1BA608
11. CONTRACT/GRANT NO.
None (in-house)
12. SPONSORING AGENCY NAME AND ADDRESS
Same as above
13. TYPE OF REPORT AND PERIOD COVERED
14. SPONSORING AGENCY CODE
EPA/600/03
15. SUPPLEMENTARY NOTES
16. ABSTRACT
To determine temperature effects on hatching success of white bass (Morone chrysops)
embryos, sample lots of fertilized eggs were exposed to 10 constant temperatures,
6 through 30 C. Exposures were begun at two stages of embryonic development,
before gastrulation and after closure of the blastopore. Embryos exposed before
gastrulation were more sensitive to extreme temperatures than those exposed after
closure of the blastopore. The percentage of normal larvae hatched from embryos
exposed before gastrulation was not significantly impaired over the temperature
range 18-26 C (P>0.05). When first exposed after blastopore closure the range of
temperatures allowing unimpaired hatching was extended to 14 - 26 C (P>0.05).
Normal larvae hatched at 14-28 C from embryos exposed before gastrulation and at
10-28 C when exposed after blastopore closure, but at the extremes in significant-
ly reduced numbers (P<0.05). Hatching took place 4.5 days after fertilization when
incubation at 14 C and 1 day after fertilization at 26 C.
The 24-hr TL50 for white bass larvae exposed within 24 hr of hatching and acclimated
at temperatures from 14 to 26 C was between 30 and 32 C and was not altered by
acclimation.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.IDENTIFIERS/OPEN ENDED TERMS C. COSATI Held/Group
Fresh water fishes
Bass
Temperature
Larvae
Embryos
Survival
Tolerances (physiology)
White Bass
Morone chrysops
Time to hatching
06F
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