United
Stater
Office
of
Water
Environmental
Protection
Regulatmr
and
Standards
Agency
Warhmgton.
DC
20460
May
1,
1986
e,
Ep',
Water
EPA
440/
5­
86­
001
QUALlTY
CRITERIA
for
W
A
m
1986
TEMPERATURE
Freshwater
Aquatic
Life
For
any
time
of
year,
there
are
two
upper
limiting
temperatures
for
a
location
(
based
on
the
important
sensitive
species
found
there
at
that
time):

1.
One
limit
consists
of
a
maximum
temperature
for
short
exposures
that
is
time
dependent
and
is
given
by
the
species­

specific
equation:

Temperature
=
(
l/
b)
(
log
[
time
3
­
a)
­
2,
C
(
C,)
10
(
min)

where:
loglo
=
logarithm
to
base
10
(
common
logarithm)

a
=
intercept
on
the
"
y"
or
logarithmic
axis
of
the
l'ine
fitted
to
experimental
data
and
which
is
available
for
some
species
from
Appendix
11­
C,
National
Academy
of
Sciences
1974
document.

b
=
slope
of
the
line
fitted
to
experimental
data
and
available
for
some
species
from
Appendix
11­
C,
of
the
National
Academy
of
Sciences
document.

and
2.
The
second
value
is
a
limit
on
the
weekly
average
temperature
that:

a.
In
the
cooler
months
(
mid­
October
to
mid­
April
in
the
north
and
December
to
February
in
the
south)
will
protect
against
mortality
of
importr
to
mid­
April
in
the
north
and
December
to
February
in
the
south)
will
protect
against
mortality
of
important
species
if
the
elevated
plume
temperature
is
suddenly
dropped
to
the
ambient
temperature,
with
the
limit
being
the
b.
acclimation
temperature
minus
apt0
when
the
lower
lethal
threshold
temperature
equals
the
ambient
water
temperature
(
in
some
regions
this
limitation
may
also
be
applicable
in
summer).

or
In
the
warmer
months
(
April
through
October
in
the
north
and
March
through
November
in
the
south)
is
determined
by
adding
to
the
physiological
optimum
temperature
(
usually
for
growth)
a
factor
calculated
as
one­
third
of
the
difference
between
the
ultimate
upper
incipient
lethal
temperature
and
the
optimum
temperature
 or
the
most
sensitive
important
species
(
and
appropriate
life
state)
that
normally
is
found
at
that
location
and
time.

or
c.
During
reproductive
seasons
(
generally
April
through
June
and
September
through
October
in
the
north
and
March
through
May
and
October
through
November
in
the
south)
the
limit
is
that
temperature
that
meets
site­

specific
requirements
for
successful
migration,

spawning,
egg
incubation,
fry
rearing,
and
other
reproductive
functions
of
important
species.
These
local
requirements
should
supersede
all
other
requirements
when
they
are
applicable.

or
d.
There
is
a
site­
specific
limit
that
is
found
necessary
to
preserve
normal
species
diversity
or
prevent
appearance
of
nuisance
organisms.
Marine
Aquatic
­
Life
In
order
to
assure
protection
of
the
characteristic
indigenous
marine
community
of
a
water
body
segment
from
adverse
thermal
effects:

a.
the
maximum
acceptable
increase
in
the
weekly
average
temperature
resulting
from
artificial
sources
is
1'

C
(
1.8
F)
during
all
seasonsofthe
year,
providtng
the
summer
maxima
are
not
exceeded;

and
b.
daily
temperature
cycles
characteristic
of
the
water
body
segment
should
not
be
altered
in
either
amplitude
or
frequency.

Summer
thermal
maxima,
which
define
the
upper
thermal
limits
for
the
communities
of
the
discharge
area,
should
be
established
on
a
site­
specific
basis.
Existing
studies
suggest
the
following
regional
limits:
0
Short­
term
Maximum
Maximum
True
Daily
Mean*
Sub
tropical
regions
(
south
of
Cape
Canaveral
and
Tampa
Bay,
Florida,
and
Hawaii
32.2'
C
(
90
°
F)
29.4O
C
(
85'
F)

Cape
Hatteras,
N.
C.,
to
Cape
Canaveral,
Fla.

Long
Island
(
south
shore)
3
0
.
6
O
C
(
87O
F)
27.8O
C
(
82O
F)
32.2'
C
(
90'
F)
29.4O
C
(
85O'F)

to
Cape
Hatteras,
N.
C.

(*
True
Daily
Mean
=
average
of
24
hourly
temperature
readings.)

Baseline
thermal
conditions
should
be
measured
at
a
site
where
there
is
no
unnatural
thermal
addition
from
any
source,

which
is
in
reasonable
proximity
to
the
thermal
discharge
(
within
5
miles)
and
which
has
similar
hydrography
to
that
of
.
the
receiving
waters
at
the
discharge.

INTRODUCTION:

The
uses
of
water
by
man
in
and
out
of
its
natural
situs
in
the
environment
are
affected
by
its
temperature.
Offstream
domestic
uses
and
instream
recreation
are
both
partially
temperature
dependent.
Likewise,
the
1
ife
associated
with
the
aquatic
environment
in
any
location
has
its
species
composition
and
activity
regulated
by
water
temperature.
Since
essentially
all
of
these
organisms
are
so­
called
"
cold
blooded"
or
poikilotherms,
the
temperature
of
the
water
regulates
their
metabolism
and
ability
to
survive
and
reproduce
effectively.

Industrial
uses
for
process
water
and
for
coolingare
likewise
regulated
by
the
water's
temperature.
Temperature,
therefore,
is
an
important
physical
parameter
which
to
some
extent
regulates
many
of
the
beneficial
uses
of
water.
The
Federal
Water
Pollution
Control
Administration
in
1967
called
temperature
a
catalyst,
a
depressant,
an
activator,
a
restrictor,
a
stimulator,

a
controller,
a
killer,
one
of
the
most
important
and
most
influential
water
quality
characteristics
to
life
in
water."
0
RATIONALE
:

The
suitability
of
water
for
total
body
immersion
is
greatly
affected
by
temperature.
In
temperate
climates,
dangers
from
exposure
to
low
temperatures
is
more
prevalent
than
exposure
to
elevated
water
temperatures.
Depending
on
the
amount
of
activity
by
the
swimmer,
comfortable
temperatures
range
from
20
°
C
to
30
°
e.
Short
durations
of
lower
and
higher
temperatures
can
be
tolerated
by
most
individuals.
For
example,
for
a
30­
minute
period,
temperatures
of
10'
C
or
35O
C
can
be
tolerated
without
harm
by
most
individuals
(
NAS,
1974).

Temperature
also
affects
the
self­
purification
phenomenon
in
water
bodies
and
therefore
the
aesthetic
and
sanitary
qualities
that
exist.
Increased
temperatures
accelerate
the
biodegradation
of
organic
material
both
in
the
overlying
water
and
in
bottom
deposits
which
makes
increased
demands
on
the
dissolved
oxygen
resources
of
a
given
system.
The
typical
situation
is
exacerbated
by
the
fact
that
oxygen
becomes
less
soluble
as
water
temperature
increases.
Thus,
greater
demands
are
exerted
on
an
increasingly
scarce
resource
which
may
lead
to
total
oxygen
depletion
and
obnoxious
septic
conditions.
These
effects
have
been
described
by
Phelps
(
1944)
,
Carp
(
1963),
and
Velz
(
1970).

Indicator
enteric
bacteria,
and
presumably
enteric
pathogens,

are
likewise
affected
by
temperature.
It
has
been
shown
that
­
both
total
and
fecal
coliform
bacteria
die
away
more
rapidly
in
the
environment
with
increasing
temperatures
(
Ballentine
and
Kittrell,
1968).

Temperature
effects
have
been
shown
for
water
treatment
processes.
Lower
temperatures
reduce
the
effectiveness
of
coagulation
with
alum
and
subsequent
rapid
sand
filtration.
In
one
study,
difficulty
was
especially
pronounced
below
5O
C
(
Hannah,
et
al.,
1967).
Decreased
temperature
also
decreases
the
effectiveness
of
chlorination.
Based
on
studies
relating
chlorine
dosage
to
temperature,
and
with
a
30­
minute
contact
time,
dosages
required
for
equivalent
disinfective
effect
increased
by
as
much
as
a
factor
of
3
when
temperatures
were
decreased
from
2
0
°
C
to
loo
C
(
Reid
and
Carlson,
1974).

Increased
temperature
may
increase
the
odor
of
water
because
of
the
increased
volatility
of
odor­
causing
compounds
(
Bumson,

1938).
Odor
problems
associated
with
plankton
may
also
be
aggravated.

The
effects
o
f
temperature
on
aquatic
organisms
have
been
the
subject
of
comprehensive
literature
reviews
(
Brett,
1956;
Fry,

1967;
FWPCA,
1967;
Kine,
1970)
and
annual
literature
reviews
published
by
the
Water
Pollution
Control
Federaticn
(
Coutant,

1968,
1969,
1970,
1971;
Coutant
and
Goodyear,
1972;
Coutant
and
Pfuderer,
1973,
1974).
Only
highlights
from
the
thermal
effects
on
aquatic
life
are
presented
here.

Temperature
changes
in
water
bodies
can
alter
the
existing
aquatic
community.
The
dominance
of
various
phytoplankton
groups
in
specific
temperature
ranges
has
been
shown.
For
example,
from
20
°
C
to
25'
C,
diatoms
predominated;
green
algae
predominated
from
30'
C:
to
35O
C
and
blue­
greens
predominated
above
3.5'
C
a
i
r
n
s
,
1956).
Likewise,
changes
from
a
coldwater
f
i
s
h
e
r
y
t
o
a
warm­
water
f
i
s
h
e
r
y
can
occur
because
temperature
may
be
d
i
r
e
c
t
l
y
l
e
t
h
a
l
t
o
a
d
u
l
t
s
o
r
f
r
y
c
a
u
s
e
a
r
e
d
u
c
t
i
o
n
of
a
c
t
i
v
i
t
y
o
r
l
i
m
i
t
0
(
c
reproduction
(
B
r
e
t
t
,
1960)

Upper
and
lower
l
i
m
i
t
s
f
o
r
temperature
have
been
established
f
o
r
many
a
q
u
a
t
i
c
organisms.
C
o
n
s
i
d
e
r
a
b
l
y
more
d
a
t
a
e
x
i
s
t
f
o
r
u
p
p
e
r
a
s
opposed
t
o
l
o
w
e
r
l
i
m
i
t
s
.
T
a
b
u
l
a
t
i
o
n
s
of
l
e
t
h
a
l
temperatures
f
o
r
f
i
s
h
and
o
t
h
e
r
organisms
a
r
e
a
v
a
i
l
a
b
l
e
(
Jones,

1
9
6
4
:
FWPCA,
1
9
6
7
NAS,
1
9
7
4
)
.
F
a
c
t
o
r
s
s
u
c
h
a
s
d
i
e
t
,
a
c
t
i
v
i
t
y
,

age,
g
e
n
e
r
a
l
h
e
a
l
t
h
,
osmotic
stress,
and
even
weather
c
o
n
t
r
i
b
u
t
e
t
o
t
h
e
l
e
t
h
a
l
i
t
y
of
t
e
m
p
e
r
a
t
u
r
e
.
The
a
q
u
a
t
i
c
species,
thermal
accumulation
s
t
a
t
e
and
exposure
t
i
m
e
a
r
e
considered
t
h
e
c
r
i
t
i
c
a
l
f
a
c
t
o
r
s
(
Parker
and
Xrenkel,
1969).

The
e
f
f
e
c
t
s
o
f
s
u
b
l
e
t
h
a
l
t
e
m
p
e
r
a
t
u
r
e
s
o
n
m
e
t
a
b
o
l
i
s
m
,

r
e
s
p
i
r
a
t
i
o
n
,
behavior,
d
i
s
t
r
i
b
u
t
i
o
n
and
migration,
feeding
rate,

growth,
and
reproduction
have
been
summarized
by
Be
S
y
l
v
a
(
1969).

Another
s
t
u
d
y
h
a
s
i
l
l
u
s
t
r
a
t
e
d
t
h
a
t
i
n
s
i
d
e
t
h
e
t
o
l
e
r
a
n
c
e
zone
t
h
e
r
e
is
encompassed
a
more
r
e
s
t
r
i
c
t
i
v
e
t
e
m
p
e
r
a
t
u
r
e
r
a
n
g
e
i
n
which
normal
a
c
t
i
v
i
t
y
and
growth
o
c
c
u
r
and
y
e
t
a
n
e
v
e
n
more
r
e
s
t
r
i
c
t
i
v
e
zone
i
n
s
i
d
e
t
h
a
t
i
n
which
normal
reproduction
w
i
l
l
occur
(
B
r
e
t
t
,
1960).

D
e
S
y
l
v
a
(
1969)
has
summarized
a
v
a
i
l
a
b
l
e
data
on
t
h
e
combined
effects
of
i
n
c
r
e
a
s
e
d
t
e
m
p
e
r
a
t
u
r
e
and
t
o
x
i
c
m
a
t
e
r
i
a
l
s
o
n
f
i
s
h
i
n
d
i
c
a
t
e
t
h
a
t
t
o
x
i
c
i
t
y
g
e
n
e
r
a
l
l
y
i
n
c
r
e
a
s
e
s
w
i
t
h
i
n
c
r
e
a
s
e
d
t
e
m
p
e
r
a
t
u
r
e
and
t
h
a
t
o
r
g
a
n
i
s
m
s
s
u
b
j
e
c
t
e
d
t
o
stress
from
t
o
x
i
c
m
a
t
e
r
i
a
l
s
a
r
e
less
t
o
l
e
r
a
n
t
o
f
temperature
extremes.

The
t
o
l
e
r
a
n
c
e
o
f
o
r
g
a
n
i
s
m
s
t
o
extremes
o
f
t
e
m
p
e
r
a
t
u
r
e
is
a
f
u
n
c
t
i
o
n
o
f
t
h
e
i
r
g
e
n
e
t
i
c
a
b
i
l
i
t
y
t
o
a
d
a
p
t
t
o
t
h
e
r
m
a
l
c
h
a
n
g
e
s
0
~
within
their
characteristic
temperature
range,
the
acclimation
temperature
prior
to
exposure,
and
the
time
of
exposure
to
the
elevated
temperature
(
Coutant,
1972).
The
upper
incipient
lethal
temperature
or
the
highest
temperature
that
50
percent
of
a
sample
of
organisms
can
survive
is
determined
on
the
organism
at
the
highest
sustainable
acclimation
temperature.
The
lowest
temperature
that
50
percent
of
the
warm
acclimated
organisms
can
survive
in
is
the
ultimate
lower
incipient
lethal
temperature.

True
acclimation
to
changing
temperatures
requires
several
days
(
Brett,
1941).
The
lower
end
of
the
temperature
accommodation
range
for
aquatic
life
is
0'
C
in
fresh
water
and
somewhat
less
for
saline
waters.
However,
organisms
acclimated
to
relatively
warm
water,
when
subjected
to
reduced
temperatures
that
under
other
conditions
of
acclimation
would
not
be
detrimental,
may
suffer
a
significant
mortality
caused
by
thermal
shock
(
Coutant,

1972).

Through
the
natural
changes
in
climatic
conditions,
the
temperatures
of
water
bodies
fluctuate
daily,
as
well
as
seasonally.
These
changes
do
not
eliminate
indigenous
aquatic
populations,
but
affect
the
existing
community
structure
and
the
geographic
distribution
of
species.
Such
temperature
changes
are
necessary
to
induce
the
reproductive
cycles
of
aquatic
organisms
and
to
regulate
other
life
factors
(
Mount,
1969).

Artificially
induced
changes
such
as
the
return
of
cooling
water
or
the
release
of
cool
hypolimnetic
waters
from
impoundments
may
alter
indigenous
aquatic
ecosystems
(
Coutant,

1972).
Entrained
organisms
may
be
damaged
by
temperature
increases
across
cooling
water
condensers
if
the
increase
is
sufficiently
great
or
the
exposure
period
sufficiently
long.

Impingement
upon
condenser
screens,
chlorination
for
slime
control,
or
other
physical
insults
damage
aquatic
life
(
Raney,

1969:
Patrick,
1969
(
b)).
However,
Patrick
(
1969(
a))
has
shown
that
algae
passing
through
condensers
are
not
injured
if
the
temperature
of
the
outflowing
water
does
not
exceed
345O
C.

In
open
waters
elevated
temperatures
nay
affect
periphyton,

benthic
invertebrates,
and
fish,
in
addition
to
causing
shifts
in
algal
dominance.
Trembley
(
1960)
studies
of
the
Delaware
River
downstream
from
a
power
plant
concluded
that
the
periphyton
population
was
considerably
altered
by
the
discharge.

The
number
and
distribution
of
bottom
organisms
decrease
as
water
temperatures
increase.
The
upper
tolerance
limit
for
a
balanced
benthic
population
structure
is
approximately
32O
C,
A
0
large
number
of
these
invertebrate
species
are
able
to
tolerate
higher
temperatures
than
those
required
for
reproduction
(
FWPCA,

1967).

In
order
to
define
criteria
for
fresh
waters,
Coutant
(
1972)

cited
the
following
was
cited
as
currently
definable
requirements:

1.
Maximum
sustained
temperatures
that
are
consistent
with
maintaining
desirable
levels
of
productivity,

2.
maximum
levels
of
metabolic
acclimation
to
warm
temperatures
that
will
permit
return
to
ambient
winter
temperatures
should
artificial
sources
of
heat
cease,

3.
Time­
dependent
temperature
1
imitations
f
o
r
survival
of
brief
exposures
to
temperature
extremes,
both
upper
and
lower,
4
.
Restricted
temperature
ranges
for
various
states
of
reproduction,
including
(
for
fish)
gametogenesis,
spawning
migration,
release
of
gametes,
development
of
the
embryo,
commencement
of
independent
feeding
(
and
other
activities)
by
j
uv
eni
1
es
,
and
temper
a
tur
es
re
qu
ired
for
met
amorphos
is,
emergence,
or
other
activities
of
lower
forms,

5.
Thermal
limits
for
diverse
species
compositions
of
aquatic
communities,
particularly
where
reduction
in
diversity
creates
nuisance
growths
of
certain
organisms,
or
where
important
food
sources
(
food
chains)
are
altered,

6.
Thermal
requirements
of
downstream
aquatic
life
(
in
rivers)
where
upstream
diminution
of
a
coldwater
resource
will
adversely
affect
downstream
temperature
requirements.

The
major
portion
of
such
information
that
is
available,

however,
is
for
freshwater
fish
species
rather
than
lower
forms
of
marine
aquatic
life.

The
temperature­
time
duration
for
short­
term
exposures
such
that
50
percent
of
a
given
population
will
survive
an
extreme
temperature
frequently
is
expressed
mathematically
by
fitting
experimental
data
with
a
staright
line
on
a
semi­
logarithmic
plot
with
time
on
the
logarithmic
scale
and
temperature
on
the
linear
scale
(
see
fig.
1).
In
equation
form
this
50
percent
mortality
relationship
is:

loglo
(
time
(
minutes))
=
a
+
b
(
Temperature
(
O
C
)
)

where:
loglo=
logarithm
to
base
10
(
common
logarithm)

a
=
intercept
on
the
"
y
"
or
logarithmic
axis
of
the
line
fitted
to
experimental
data
and
which
is
available
for
some
species
from
Appendix
11­
C,
of
the
National
Academy
of
Sciences
document.

b
=
slope
of
the
line
fitted
to
experimental
data
and
which
is
available
for
some
species
from
Appendix
11­
C,
of
the
National
Academy
of
Sciences
document.

To
provide
a
safety
factor
so
that
none
or
only
a
few
organisms
will
perish,
it
has
been
found
experimentally
that
a
criterion
of
2O
C
below
maximum
temperature
is
usually
sufficient
(
Black,
1953).
To
provide
safety
for
all
the
organisms,
the
temperature
causing
a
median
mortality
for
5
0
percent
of
the
population
would
be
calculated
and
reduced
by
2'

C
in
the
case
of
an
elevated
temperature.
Available
scientific
information
includes
upper
and
lower
incipient
lethal
temperatures,

coefficients
I1at1
and
llbll
for
the
thermal
resistance
equation,
and
information
of
size,
life
stage,
and
geographic
source
of
the
particular
test
species
(
Appendix
11­
C,
NAS,
1974).

Maximum
temperatures
for
an
extensive
exposure
(
e.
g.,
more
than
1
week)
must
be
divided
into
those
for
warmer
periods
and
winter.
Other
than
for
reproduction,
the
most
temperature­

sensitive
life
function
appears
to
be
growth
(
Coutant,
1972).

Coutant
(
1972)
has
suggested
that
a
satisfactory
estimate
of
a
limiting
maximum
weekly
mean
temperature
may
be
an
average
of
the
optimum
temperature
for
growth
and
the
temperature
 or
zero
net
growth.

Because
of
the
difficulty
in
determining
the
temperature
of
zero
net
growth,
essentially
the
same
temperature
can
be
derived
by
adding
to
the
optimum
essentially
to
temperature
(
for
growth
or
other
physiological
functions)
a
factor
calculated
as
one­

third
of
the
difference
between
the
ultimate
upper
incipient
lethal
temperature
and
the
optimum
temperature
(
NAS,
1974).
In
equation
form:

Maximum
weekly
(
ultimate
upper
optimum)
average
=
optimum
+
1/
3
(
incipient
lethal
­
temperature)
temperature
temperature
(
temperature)

Since
temperature
tolerance
varies
with
various
states
of
development
of
a
particular
species,
the
criterion
f
o
r
a
­
p
a
r
t
i
c
u
l
a
r
l
o
c
a
t
i
o
n
would
be
c
a
l
c
u
l
a
t
e
d
f
o
r
t
h
e
most
important
l
i
f
e
form
l
i
k
e
l
y
t
o
be
p
r
e
s
e
n
t
d
u
r
i
n
g
a
p
a
r
t
i
c
u
l
a
r
month.
One
c
a
v
e
a
t
i
n
using
t
h
e
maximum
weekly
mean
temperature
is
t
h
a
t
t
h
e
l
i
m
i
t
f
o
r
s
h
o
r
t­
t
e
r
m
exposure
must
n
o
t
be
exceeded.
Example
c
a
l
c
u
l
a
t
i
o
n
s
f
o
r
predicting
t
h
e
summer
maximum
temperatures
f
o
r
short­
term
s
u
r
v
i
v
a
l
and
f
o
r
extensive
exposure
f
o
r
various
f
i
s
h
s
p
e
c
i
e
s
a
r
e
p
r
e
s
e
n
t
e
d
i
n
T
a
b
l
e
11.
These
c
a
l
c
u
l
a
t
i
o
n
s
u
s
e
t
h
e
above
e
q
u
a
t
i
o
n
s
and
d
a
t
a
from
EPA's
Environmental
Research
Laboxatory
i
n
Duluth.

The
w
i
n
t
e
r
maximum
t
e
m
p
e
r
a
t
u
r
e
must
n
o
t
exceed
t
h
e
ambient
water
t
e
m
p
e
r
a
t
u
r
e
by
more
t
h
a
n
t
h
e
amount
o
f
change
a
specimen
acclimated
t
o
t
h
e
plume
temperature
can
t
o
l
e
r
a
t
e
.
Such
a
change
c
o
u
l
d
o
c
c
u
r
by
a
c
e
s
s
a
t
i
o
n
of
t
h
e
s
o
u
r
c
e
of
h
e
a
t
o
r
by
t
h
e
specimen
being
d
r
i
v
e
n
from
a
n
a
r
e
a
by
a
d
d
i
t
i
o
n
o
f
b
i
o
c
i
d
e
s
o
r
o
t
h
e
r
f
a
c
t
o
r
s
.
However,
there
are
inadequate
d
a
t
a
t
o
estimate
a
s
a
f
e
t
y
f
a
c
t
o
r
f
o
r
t
h
e
Isno
stress"
l
e
v
e
l
from
c
o
l
d
shocks
(
NAS,

1974).
F
i
g
u
r
e
2
was
developed
from
a
v
a
i
l
a
b
l
e
d
a
t
a
i
n
t
h
e
l
i
t
e
r
a
t
u
r
e
(
ERL­
Duluth,
1
9
7
6
)
and
can
be
used
f
o
r
e
s
t
i
m
a
t
i
n
g
a
l
l
o
w
a
b
l
e
winter
temperature
increases.

Coutant
(
1
9
7
2
)
h
a
s
reviewed
t
h
e
e
f
f
e
c
t
s
of
t
e
m
p
e
r
a
t
u
r
e
on
a
q
u
a
t
i
c
l
i
f
e
reproduction
and
development.
Reproductive
e
v
e
n
t
s
are
noted
a
s
perhaps
t
h
e
most
t
h
e
r
m
a
l
l
y
restricted
of
a
l
l
l
i
f
e
p
h
a
s
e
s
assuming
o
t
h
e
r
f
a
c
t
o
r
s
a
r
e
a
t
o
r
n
e
a
r
optimum
l
e
v
e
l
s
.

N
a
t
u
r
a
l
s
h
o
r
t­
t
e
r
m
t
e
m
p
e
r
a
t
u
r
e
f
l
u
c
t
u
a
t
i
o
n
s
a
p
p
e
a
r
t
o
c
a
u
s
e
reduced
reproduction
of
f
i
s
h
and
invertebrates.
TABLE
11.­
Example
Calculated
Values
for
Maxima
for
Survival
for
Juveniles
and
Adults
During
the
Summer
(
Centigrade
and
Fahrenheit).

Species
Growtha
Maxima
Maximum
Weekly
Average
Temperatures
for
Growth
and
Short­
Term
b
Atlantic
salmon
Bigmouth
buffalo
Black
crappie
Bluegill
Brook
trout
Carp
Channel
catfish
Coho
salmon
Emerald
shiner
Freshwater
drum
Lake
herring
(
Cisco)
Largemouth
bass
Northern
pike
Rainbow
trout
Sauger
Smallmouth
bass
Smallmouth
buffalo
Sockeye
salmon
Striped
bass
Threadfin
shad
White
bass
White
crappie
White
sucker
Yellow
perch
20
(
68)

27
(
81)
32
(
90)
19
(
66)

32
(
90)
18
(
64)
30
(
86)

17
(
63)
32
(
90)
28
(
82)
19
(
66)
25
(
77)
29
(
84)

18
(
64)

28
(
82)
28
(
82)
29
(
84)
23
(
73)

35
(
95)
24
(
75)

35
(
95)
24
(
75)

25
(
77)

30
(
86)
24
(
75)
34
(
93)

22
(
72)

a
­
Calculated
according
to
the
equation
(
using
optimum
temperature
for
growth)

maximum
weekly
average
temperature
for
growth
=
optimum
temperature
+
1/
3
(
ultimate
incipient
lethal
temperature­

optimum
temperature.

b
­
Based
on
temperature
(
OC)
=
l
/
b
(
log"
time(
min.)
­
a)

2O
C,
acclimation
at
the
maximum
weekly
average
temperature
 or
summer
growth,
and
data
in
Appendix
11­
C
of
Water
Quality
Criteria,
published
by
National
Academy
of
Sciences.

c
­
Based
on
data
for
larvae
(
ERL­
Duluth,
1976).
0
­.
,
There
are
indadequate
data
available
quantitating
the
most
temperature­
sensitive
life
stages
among
various
aquatic
species.

Uniform
elevation
of
temperature
a
few
degrees
but
still
within
the
spawning
range
may
lead
to
advanced
spawning
for
spring
spawning
species
and
delays
for
fall
spawners.
Such
changes
may
not
be
detrimental
unless
asynchrony
occurs
between
newly
hatched
juveniles
and
their
normal
food
source.
Such
asynchrony
may
be
most
pronounced
among
anadromous
species
or
other
migrants
who
pass
from
the
warmed
area
to
a
normally
chilled,
unproductive
area.
Reported
temperature
data
on
maximum
temperatures
for
spawning
and
embryo
survival
have
been
summarized
in
Table
12
(
from
ERL­
Duluth
1976).

Although
the
limiting
effects
of
thermal
addition
to
estuarine
and
marine
waters
are
not
as
conspicuous
in
the
fall,

winter,
and
spring
as
during
the
summer
season
of
maximum
heat
stress,
nonetheless
crucial
thermal
limitations
do
exist.
Hence,

it
is
important
that
the
thermal
additions
to
the
receiving
waters
be
minimized
during
all
seasons
of
the
year.
Size
of
harvestable
stocks
of
commercial
fish
and
shellfish,
particularly
near
geographic
limits
of
the
fishery,
appear
to
be
markedly
influenced
by
slight
changes
in
the
long­
term
temperature
regime
(
Dow,
1973).

Jefferies
and
Johnson
(
1974)
studied
the
relationship
between
temperature
and
annual
variation
in
7­
year
catch
data
for
winter
flounder,
Pseudopleuronectes
_­__­_­­_­
I
americanus
in
Narragansett
Bay,

Rhode
Island,
revealed
that
a
78
percent
decrease
in
annual
catch
correlated
closely
with
a
0.5OC
increase
in
the
average
temperature
over
the
30­
month
period
between
spawning
and
recruitment
into
the
fishery.
Sissenwine's
1974
model
predicts
a
68
percent
reduction
of
recruitment
in
ye1
Powtail
flounder,

Limanda
­­­
ferrugiia,
with
a
l0C
long­
term
elevation
in
southern
New
England
waters.
TABLE
12.

Summary
of
Reported
Values
for
Maxima
for
Embryo
Survival
During
the
Spawning
Season
(
Centigrade
and
Fahrenheit)
Maximum
Weekly
Average
Temperature
for
Spawning
and
Short­
Term
Species
Atlantic
Salmon
Bigmouth
Buffalo
Black
Crappie
Bluegill
Brook
Trout
carp
Channel
Catfish
Coho
Salmon
Emerald
Shiner
Freshwater
Drum
Lake
Herring
(
Cisco)
Largemouth
Bass
Northern
Pike
Rainbow
Trout
Sauger
Smallmouth
Bass
Smallmouth
Buffalo
Sockeye
Salmon
Striped
Bass
Threadfin
Shad
White
Bass
White
Crappie
White
Sucker
Yellow
Perch
Spawning,
Embryo
Survivalb
5
17
25
9
21
27
10
24
21
3
21
11
9
17
17
10
18
18
17
18
10
12
I
10
(
41)
7
77
1
34
70)
33
(
63)
27
48)
13
81)
29
50)
13
75)
28
70)
26
37)
8
70)
27
52)
19
48)
13
50)
21
63
1
21
13
63)
50)
64
1
24
64
1
34
63)
26
23
20
64)

20
50)
54)

a
­
the
optimum
or
mean
of
the
range
of
spawning
temperatures
reported
for
the
species
(
ERL­
Duluth,
1976).

b
­
the
upper
temperature
for
successful
incubation
and
hatching
reported
for
the
species
(
ERL­
Duluth,
1976)
­

c
­
upper
temperature
for
spawning.
Community
balance
can
be
influenced
strongly
by
such
temperature­
dependent
factors
as
rates
of
reproduction,

recruitment,
and
growth
of
each
component
population.
A
few
degrees
elevation
in
average
monthly
temperature
can
appreciably
alter
a
community
through
changes
in
interspecies
relationships.

A
50
percent
reduction
in
the
softshell
clam
fishery
in
Maine
by
the
green
crab,
Carcinus
maenus,
illustrates
how
an
increase
in
winter
temperatures
can
establish
new
predator­
prey
relationships.
Over
a
period
of
4
years,
there
was
a
natural
amelioration
of
temperature
and
the
monthly
mean
for
the
coldest
month
of
each
year
did
not
fall
below
2OC.
This
apparently
precluded
appreciable
ice
formation
and
winter
cold
kill
of
the
green
crab
and
permitted
a
major
expansion
of
its
population,

with
increased
predation
of
the
softshell
clam
resulting
(
Glude,

1954:
Welch,
1968).

Temperature
is
a
primary
factor
controlling
reproduction
and
can
influence
many
events
of
the
reproductive
cycle
from
gametogenesis
to
spawning.
Among
marine
invertebrates,

initiation
of
reproduction
(
gametogenesis)
is
often
triggered
during
late
winter
by
attainment
of
a
minimum
environmental
threshold
temperature.
In
some
species,
availability
of
adequate
food
is
also
a
requisite
(
Pearse,
1970;
Sastry,
1975:
devlaming,

1971).
Elevated
temperature
can
limit
gametogenesis
by
preventing
accumulation
of
nutrients
in
the
gonads.
This
problem
could
be
acute
during
the
winter
if
food
availability
and
feeding
activity
is
reduced.
Most
marine
organisms
spawn
during
the
spring
and
summer;
gametogenesis
is
usually
initiated
during
the
0
previous
fall.
It
should
also
be
noted
that
some
species
spawn
only
during
the
fall
(
herrinhg)
,
while
others
during
the
winter
and
very
early
spring.
At
the
higher
latitudes,
winter
breeders
include
such
estuarine
community
dominants
as
acorn
barnacles,

Balanus
balanus
and
B.
balanoides,
the
edible
blue
mussel
Mytilus
_
­­
­

­­­­
I
edulis
sea
urchin,
Strongylocentrotus
drobachiensis,
sculpin,

and
the
winter
flounder,
Pseudopleuronectes
­
americanus.
The
two
boreal
barnacles
require
temperatures
below
10
°
C
before
egg
production
will
be
initiated
(
Crisp,
1957).
It
is
clear
that
adaptations
for
reproduction
exist
which
are
dependent
on
temperature
conditions
close
to
the
natural
cycle.

Juvenile
and
adult
fish
usually
thermoregulate
behaviorally
by
moving
to
water
having
temperatures
closest
to
their
thermal
preference.
This
provides
a
thermal
environment
which
approximates
the
optimal
temperature
for
many
physiological
functions,
including
growth
(
Neil1
and
Magnuson.
1974).
As
a
consequence,
fishes
usually
are
attracted
to
heated
water
during
the
fall,
winter,
and
spring.
Avoidance
will
occur
as
warmer
temperature
exceeds
the
preferendum
by
1
to
3OC
(
Coutant,
1975).

This
response
precludes
problems
of
heat
stress
for
juvenile
and
adult
fishes
during
the
summer,
but
several
potential
problems
exist
during
the
other
seasons.
The
possibility
of
cold
shock
and
death
of
plume­
entrained
fish
resulting
from
winter
plant
shutdown
is
well
recognized.
Also,
increased
incidence
of
disease
and
a
deterioration
of
physiological
condition
has
been
observed
among
plume­
entrained
fishes,
perhaps
because
of
insufficient
food
(
Massengill,
1973).
A
weight
loss
of
approximately
10
percent
for
each
lo
C
rise
in
water
temperature
has
been
observed
in
fish
when
food
is
absent.
(
Phillips
et
al.,

1960)
There
may
also
be
indirect
adverse
effects
on
the
indigenous
community
because
of
increased
predation
pressure
if
thermal
addition
leads
to
a
concentration
of
fish
which
are
dependent
on
this
community
for
their
food.

Fish
migration
is
often
linked
to
natural
environmental
temperature
cycles.
In
early
spring,
fish
employ
temperature
as
their
environmental
cue
to
migrate
northward
(
e.
g.,
menhaden,

bluefish)
or
to
move
inshore
(
winter
flounder).
Likewise,
water
temperature
strongly
influences
timing
of
spawning
runs
ofan­

adromous
fish
into
rivers
(
Leggett
and
Whitney,
1972).
In
the
autumn,
a
number
of
juvenile
marine
fishes
and
shrimp
are
dependent
on
a
drop
in
temperature
to
trigger
their
migration
from
estuarine
nursery
grounds
for
oceanic
dispersal
or
southward
migration
(
Lund
and
Maltezos,
1970;
Talbot,
1966).

Thermal
discharges
should
not
alter
diurnal
and
tidal
temperature
variations
normally
experienced
by
marine
communities.
Laboratory
studies
show
thermal
tolerance
to
be
enhanced
when
animals
are
maintained
under
a
diurnally
fluctuating
temperature
regime
rather
than
at
a
constant
temperature
(
Costlow
and
Bookhout,
1971;
Furch,
1972;
Hoss,
et
al.,).
A
daily
cyclic
regime
can
be
protective
additionally
as
it
reduces
duration
of
exposure
to
extreme
temperatures
(
Pearce,

1969;
Gonzalez,
1972).
0
Summer
thermal
maxima
should
be
established
to
protect
the
various
marine
communities
within
each
biogeographic
region.

During
the
summer,
naturally
elevated
temperatures
may
be
of
­
1
sufficent
magnitude
to
cause
death
or
emigration
(
Glynn,
1968;

Vaughn,
1961).
This
more
commonly
occurs
in
tropical
and
warm
temperate
zone
waters,
but
has
been
reported
for
enclosed
bays
and
shallow
waters
in
other
regions
as
well
(
Nichols,
1918).

Summer
heat
stress
also
can
contribute
to
increased
incidence
of
disease
or
parasitism
(
Sinderman,
1965)
:
reduce
or
block
sexual
maturation
(
Thorhaug,
et
al.,
1971:
deVlaming,
1972);
inhibit
or
block
embryonic
cleavage
of
larval
development
(
Calabrese,
1969)
;

reduce
feeding
and
growth
of
juveniles
and
adults
(
011a
and
Studholme,
1971)
:
result
in
increased
predation
(
Gonzalez,
1972);

and
reduce
productivity
of
macroalgae
and
seagrasses
(
South
and
Hill,
1970;
Zieman,
1970).
The
general
ceilings
set
forth
here
are
derived
from
studies
delineating
limiting
temperatures
for
the
more
thermally
sensitive
species
or
communities
of
a
biogeographic
region.

Thermal
effects
data
are
presently
insufficient
to
set
general
temperature
limits
for
all
coastal
biogeographic
regions.

The
data
enumerated
in
the
Appendix,
plus
any
additional
data
subsequently
generated,
should
be
used
to
develop
thermal
limits
which
specifically
consider
communities
relevant
to
given
water
bodies.

(
QUALITY
CRITERIA
FOR
WATER,
JULY
1976)
PB­
263943
SEE
APPENDIX
C
FOR
METHODOLOGY
