Document ID: EPA-HQ-OW-2004-0002-1023
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2005-10-18T04:00Z

Abundance
And
Size
Of
Dominant
Winter­
Immigrating
Fish
Larvae
At
Two
Inlets
Into
Pamlico
Sound,
North
Carolina
William
E.
Hettler,
Jr.
National
Marine
Fisheries
Service
National
Oceanic
and
Atmospheric
Administration
Southeast
Fisheries
Science
Center
101
Pivers
Island
Road
Beaufort,
North
Carolina,
USA
28516­
9722
ABSTRACT­­
Weekly
sampling
for
the
larvae
of
six
species
of
ocean­
spawning,
estuarine­
dependent
fishes
was
conducted
from
October
1994
to
April
1995
inside
Oregon
Inlet
and
Ocracoke
Inlet,
two
major
inlets
into
Pamlico
Sound,
North
Carolina.
Atlantic
menhaden,
Brevoortia
tyrannus,
were
similar
in
average
density
at
both
inlets;
Atlantic
croaker,
Micropogonias
undulatus,
and
summer
flounder,
Paralichthys
dentatus,
were
more
abundant
at
Oregon
Inlet;
spot,
Leiostomus
xanthurus,
pinfish,
Lagodon
rhomboides,
and
southern
flounder,
P.
lethostigma,
were
more
abundant
at
Ocracoke
Inlet.
Atlantic
croaker
were
significantly
larger
at
Oregon
Inlet
at
the
beginning
and
end
of
the
ingress
season,
whereas
Atlantic
menhaden
were
significantly
smaller
at
Ocracoke
Inlet
at
the
end
of
the
season
(
ca.
12
mm
vs.
27
mm).
Abundance
data
from
Oregon
and
Ocracoke
inlets
were
compared
with
abundance
data
collected
during
the
same
period
at
Beaufort
Inlet
and
with
data
from
a
previous
monthly
survey
conducted
six
years
earlier
at
the
same
stations
at
Oregon
and
Ocracoke
inlets.
Winter
temperatures
were
similar
at
both
inlets,
but
Ocracoke
Inlet
was
warmer
during
spring.
Oregon
Inlet
was
less
saline
than
Ocracoke
Inlet
at
every
sampling
event.

Pamlico
Sound,
the
largest
barrier
island
estuary
in
the
United
States
(
5,200
km2),
supports
numerous
fisheries
either
indirectly
as
juvenile
habitat
or
directly
as
fishing
grounds.
Major
fisheries
include
species
of
Clupeidae,
Paralicthyidae,
and
Sciaenidae.
Most
species
of
these
families
spawn
in
the
ocean,
after
which
their
larvae
pass
through
inlets
before
reaching
estuarine
nurseries.
Data
on
the
ingress
through
inlets
of
larvae
of
these
species
are
essential
in
understanding
variability
in
annual
recruitment.
The
only
publication
describing
the
seasonal
abundance
of
fish
larvae
in
inlets
to
Pamlico
Sound
was
based
on
once­
monthly
sampling
(
Hettler
and
Barker
1993).
Since
that
study,
analysis
of
a
daily
sampling
experiment
at
Beaufort
Inlet
concluded
that
sampling
weekly
or
more
often
significantly
increases
confidence
in
larval
abundance
estimates
(
Hettler
et
al.
1997)
.
The
objective
of
my
study
was
to
sample
weekly
at
two
of
the
three
inlets
connecting
Pamlico
Sound
directly
to
the
Atlantic
Ocean
(
Oregon
Inlet
and
Ocracoke
Inlet)
to
compare
their
relative
contribution
as
larval
fish
pathways
to
the
marine
species
nursery
grounds
in
the
sound
and
adjacent
tributaries
as
identified
by
Epperly
and
Ross
(
1986).

METHODS
Oregon
Inlet
is
the
only
inlet
into
Pamlico
Sound
north
of
Cape
Hatteras
and
lies
in
the
temperate
Virginian
Province
near
the
southern
end
of
the
Labrador
Current
(
Fig.
1:
Study
Location.).
Ocracoke
Inlet,
the
largest
inlet
in
North
Carolina
and
one
of
two
inlets
connecting
Raleigh
Bay
(
located
between
Cape
Hatteras
and
Cape
Lookout)
with
Pamlico
Sound,
lies
in
the
subtropical
Carolinian
Province.
These
inlets
were
sampled
for
27
consecutive
weeks
between
October
1994
and
April
1995
during
the
ingress
of
larvae
of
six
targeted
species
of
fall­
winter
spawning
fishes,
five
of
which
contribute
85%
of
the
total
commercial
fish
catch
in
North
Carolina
(
Miller
et
al.
1984).

Inside
each
inlet
a
single
sampling
station
was
established
in
the
center
of
the
main
floodtide
channel
(
Oregon
Inlet
station:
35E
46.3'
N,
75E
33.5'
W
;
Ocracoke
Inlet
station:
35E
06.4'
N,
75E
59.5'
W).
The
deepest
water
at
each
station
was
7
m
and
the
channel
width
was
about
300
m.
Inlets
were
sampled
one
night
each
week
on
adjacent
nights
(
quasisynoptic
Each
night's
sampling
consisted
of
12
repetitive
tows,
about
10
minutes
apart,
with
a
0.8­
ml,
800
micron­
mesh­
net
on
a
1­
m­
diameter,
sled­
mounted,
aluminum
frame
towed
at
a
net
speed
of
1
m/
sec.
A
tow
consisted
of
actively
towing
the
net
in
the
deepest
water
along
the
axis
of
the
channel
down
to
the
bottom
and
back
to
the
surface.
Tows
were
always
made
into
the
current.
A
flow­
meter
measured
the
volume
of
water
passing
through
the
net.
Each
tow
took
4
minutes,
filtering
approximately
200
m3
of
water.
Preceding
each
tow,
temperature
and
salinity
casts
were
taken
with
a
SeaBird
19
CTD
and
direction
of
tidal
flow
was
recorded.
CTD
data
were
averaged
for
the
entire
water
column
and
all
tows
on
a
given
date
(
Fig.
2:
Mean
water
column
temperature
and
salinity
at
Oregon
Inlet
and
Okracoke
Inlet,
North
Carolina
for
weekly
sampling
during
the
1994­
1995
immigration
period.),
because
the
oblique
net
tows
integrated
the
larval
catch
from
throughout
the
water
column
and
the
vertical
distribution
of
the
larvae
was
unknown.
However,
the
surface
and
bottom
values
were
compared
to
show
the
amount
of
temperature
and
salinity
stratification
in
the
channel
at
each
station
(
Fig.
3:
Difference
between
the
surface
and
the
bottom
temperature
and
salinity
at
Oregon
Inlet
and
Ocracoke
Inlet,
North
Carolina
during
the
1994­
1995
immigration
period.).
As
observed
from
the
vessel,
the
channel
currents
were
flooding
on
15
of
the
27
dates
at
Oregon
Inlet
and
on
20
of
the
27
dates
at
Ocracoke
Inlet.

On
board
the
vessel,
larvae
were
preserved
in
70%
ethyl
alcohol.
In
the
laboratory,
larvae
were
sorted
by
species
and
counted.
Up
to
10
larvae
of
each
species
from
each
tow
were
measured
to
the
nearest
0.1
mm
standard
length.
Larval
abundance
was
calculated
as
the
number
per
100
ml
and
plotted
as
the
weekly
mean
density
(+
1
standard
error)
of
the
individual
tow
densities
by
inlet
and
date.
Lengths
were
plotted
as
the
mean
standard
length
of
up
to
120
larvae
of
each
species
at
each
inlet
each
week
(
ñ
1
standard
error).

Wilcoxon
rank
sum
tests
were
used
to
compare
densities
of
species
between
inlets.
To
examine
the
relative
contribution
by
inlet
for
each
species,
the
seasonal
weekly
density
by
species
for
Oregon
Inlet
and
Ocracoke
fnict
was
compared
with
data
collected
during
the
same
period
in
a
separate
study
at
Beaufort
Inlet
(
Warlen
1994;
S.
Warlen,
NMFS
Beaufort
Laboratory,
personal
communication).
For
this
comparison,
it
should
be
recognized
that
the
Beaufort
Inlet
study
results
are
used
as
proxy
data
in
the
absence
of
data
collected
with
the
same
methods
as
at
Oregon
and
Ocracoke
inlets.
In
the
Beaufort
study,
a
2­
m2,
1000
micron­
mesh
neuston
net
was
fished
passively
in
the
tidal
current
at
the
surface.
In
both
studies,
however,
the
data
were
standardized
to
densities
per
unit
volume
by
the
use
of
flow
meters.

RESULTS
AND
DISCUSSION
TEMPERATURE
AND
SALINITY
The
inlets
were
similar
in
temperature,
except
that
Ocracoke
Inlet
warmed
at
a
faster
rate
after
late
February
than
did
Oregon
Inlet
(
Fig.
2:
Mean
water
column
temperature
and
salinity
at
Oregon
Inlet
and
Okracoke
Inlet,
North
Carolina
for
weekly
sampling
during
the
1994­
1995
immigration
period.).
During
February,
when
abundance
of
most
larval
species
was
low,
temperature
at
both
inlets
dropped
to
less
than
5C.

Salinity
as
high
as
33
ppt
was
observed
twice
at
Ocracoke
Inlet,
once
in
late
autumn
and
once
in
early
spring,
a
time
when
salinity
at
Oregon
Inlet
was
about
20
ppt.
Salinity
at
Oregon
Inlet
was
always
5­
20
ppt
lower
than
Ocracoke
Inlet
and
in
February
was
as
low
as
4
ppt.
Salinities
lower
than
10
ppt
in
Oregon
Inlet
in
combination
with
low
temperatures
occurred
eight
times.
The
physiological
consequences
of
low
salinities
and
temperatures
on
ocean­
spawned
larvae
is
only
partially
known.
For
example,
Brevoortia
tyrannus
(
Atlantic
menhaden)
larvae
died
in
laboratory
experiments
at
salinities
<
5
ppt
and
temperatures
<
5
C.
In
these
experiments,
however,
50%
mortality
in
<
48
hours
also
occurred
at
high
salinity
(
30
ppt)
and
low
temperatures
(<
5
C)
(
Lewis,
1966).
In
other
laboratory
experiments,
Leiostomus
xanthuras
(
spot)
were
determined
to
be
more
cold
sensitive
at
10
C
than
Micropogonias
undulatus
(
Atlantic
croaker),
but
test
salinities
were
not
given
(
Hoss
et
al.
1988).
Their
study
concluded
that
during
severe
winters
many
early
arriving
larvae
in
estuaries
are
killed
and
that
only
late
arriving
larvae
survive
for
recruitment
into
the
fishery.

Twice
at
each
inlet,
the
temperature
difference
between
the
surface
and
bottom
water
equaled
or
exceeded
1
C
in
the
7­
m­
deep
channel,
but
generally
there
was
little
thermal
stratification
(
Fig.
3:
Difference
between
the
surface
and
the
bottom
temperature
and
salinity
at
Oregon
Inlet
and
Ocracoke
Inlet,
North
Carolina
during
the
1994­
1995
immigration
period.).
On
several
occasions
the
water
column
was
colder
at
the
surface
when
strong,
cold
winds
were
present.
On
the
other
hand,
salinity
was
often
positively
stratified,
as
much
as
6
ppt
less
saline
at
the
surface.
At
Oregon
Inlet
during
early
February,
when
there
was
a
5
ppt
difference
between
the
surface
and
bottom,
the
surface
was
1C
colder
than
the
bottom.
At
this
time,
the
current
direction
at
the
surface
was
ebbing.

Table
1.
Average
weekly
densities
(
number
per
100
m3
ñ
1
standard
error)
at
Oregon
Inlet
and
Ocracoke
Inlet
(
0.8­
m2
net,
this
study)
compared
with
Beaufort
Inlet
(
2­
m2
net,
S.
Warlen,
NMFS,
Beaufort
Laboratory,
personal
communication)
during
the
October
1994
­
April
1995
immigration
season
(
n=
27
weeks).
Values
connected
with
a
dashed
line
are
not
significantly
different
(
Wilcoxon
rank
sum
test,
a
=
0.05).

Species
Oregon
Inlet
Ocracoke
Inlet
Beaufort
Inlet
Brevoortia
tyrannus
43.2(+
4.1)
43.5(+
4.9)
22.9(+
8.4)
Lagodon
rhomboides
0.6
(+
0.1)
1.7
(+
0.3)
12.4
(+
3.9)
Leiostomus
xanthurus
4.4
(+
1.0)
21.1
("
4.8)
4.8
("
18.7)
Micropogonias
undulatus
155.5(
ñ27.1)
26.9
(+
3.9)
25.7
(+
6.1)
Paralichthys
dentatus
1.0
(
ñ0.2)
0.3
(+
0.1)
0.3
(+
0.2)
Paralichthys
lethostigma
0.1
(+
0.1)
0.5
(+
0.1)
0.8
(+
0.3)

ABUNDANCE
Unlike
the
other
five
selected
species,
Atlantic
menhaden
were
not
significantly
different
in
average
weekly
density
at
any
inlet,
although
fewer
appeared
to
be
caught
at
Beaufort
Inlet
during
the
year
(
Table
1).
Spot
were
less
abundant
at
Oregon
Inlet
than
the
other
inlets,
but
Atlantic
croaker
were
most
abundant
at
Oregon
Inlet.
Pinfish
(
Lagodon
rhomboides)
and
southern
flounder
(
P.
lethostigma)
were
different
in
density
among
all
inlets.
Spot,
pinfish,
and
southern
flounder
increased
in
density
towards
the
south,
whereas
Atlantic
croaker
and
summer
flounder
decreased,
which
is
the
expected
pattern
based
on
the
known
distribution
of
these
species
(
Fahay
1983).
North
Carolina
is
the
center
of
the
known
spawning
range
of
Atlantic
menhaden
(
Friedland
et
al.
1996),
and
similar
densities
at
these
inlets
is
not
surprising
even
though
the
spawning
locations
contributing
Atlantic
menhaden
larvae
to
each
inlet
is
unknown.

One
or
more
prominent
peaks
in
densities
of
each
species
occurred
at
one
or
both
inlets
during
the
season
(
Fig.
4:
Mean
densities
of
six
selected
species
of
fish
larvae
at
Oregon
Inlet
and
Ocracoke
Inlet,
North
Carolina,
during
the
1994­
1995
larval
fish
immigration
period.).
Atlantic
croaker
were
dominant
during
the
early
season
at
Oregon
Inlet
with
a
weekly
mean
density
of
>
2000
per
100
m3
in
late
October.
In
one
tow
on
29
October
1994,
the
catch
density
was
3000
larvae
per
100
m3.
Another
pulse
of
Atlantic
croaker
entered
Oregon
Inlet
in
early
December,
a
week
after
summer
flounder
peaked
in
density
at
that
inlet.
Peak
summer
flounder
densities
at
Oregon
Inlet
preceded
the
period
of
peak
recruitment
into
Ocracoke
by
more
than
3
months.
Summer
flounder
were
found
to
peak
in
Beaufort
Inlet
in
February
(
Burke
et
al.
1991).
The
peak
abundance
of
Atlantic
croaker
and
summer
flounder
larvae
observed
early
in
the
season
at
Oregon
Inlet
compared
to
the
two
inlets
south
of
Cape
Hatteras,
suggests
that
these
species
are
coming
from
spawning
areas
that
have
cross­
shelf
transport
routes
north
of
Cape
Hatteras.
Southern
flounder,
which
were
not
abundant
at
Oregon
Inlet,
peaked
at
Ocracoke
Inlet
in
mid­
February,
the
same
period
as
reported
earlier
for
Beaufort
Inlet
by
Burke
et
al.
(
1991).
Gulf
flounder
(
P.
albigutta),
an
abundant
paralichyid
south
of
Cape
Hatteras,
were
not
caught
at
Oregon
Inlet
and
therefore
are
not
considered
further.
The
largest
numbers
of
pinfish
were
caught
at
both
inlets
in
mid­
January.
Spot
also
were
most
abundant
in
mid­
January,
but
only
at
Ocracoke.
Early
in
the
season
Atlantic
menhaden
were
more
abundant
at
Oregon
Inlet
than
at
Ocracoke,
but
both
inlets
had
high
numbers
in
mid­
December
and
mid­
January.
The
high
densities
of
Atlantic
menhaden
at
Oregon
Inlet
in
November,
a
month
before
significant
ingress
into
Ocracoke,
suggests
that
spawning
or
favorable
cross­
shelf
transport
currents
supplying
these
larvae
took
place
north
of
Cape
Hatteras.
In
early
October,
concentrations
of
Atlantic
menhaden
larvae
have
been
reported
as
far
south
as
Currituck
Beach,
North
Carolina,
about
60
km
north
of
Oregon
Inlet
(
Kendall
and
Reintjes
1974).
If
this
distribution
also
occurred
in
October
1994,
larvae
would
have
been
in
position
for
transport
to
the
inlet
by
November.
The
largest
densities
of
Atlantic
menhaden
observed
during
the
season
came
into
Ocracoke
Inlet
in
mid­
March.
Except
for
southern
flounder,
the
abundance
of
all
other
species
was
low
in
February
at
both
inlets.

Seasonal
density
patterns
in
1994­
1995
were
different
than
those
reported
for
1988­
1989
(
Hettler
and
Barker
1993).
In
1988­
1989,
sampling
was
conducted
monthly
with
the
same
0.8­
m2,
800
micron­
mesh­
net
on
a
1­
m­
diameter
frame
at
the
same
stations
as
in
1994­
1995.
Because
large
variablity
in
density
estimates
can
occur
as
a
result
of
infrequent
sampling,
monthly
densities
probably
do
not
represent
average
monthly
values
(
Hettler
et
al.
1997).
However,
in
that
earlier
study,
Atlantic
menhaden
were
most
abundant
at
Ocracoke
Inlet
in
February
(
92
per
100
m3)
and
at
Oregon
Inlet
in
March
(
222
per
100
m3),
whereas
in
the
present
study
density
was
highest
in
mid­
March
at
Ocracoke
Inlet
and
mid­
December
at
Oregon
Inlet.
Warlen
(
1994)
also
recorded
peak
menhaden
density
(
130
per
100
m3)
in
February
1989
at
Beaufort
Inlet,
earlier
that
year
than
any
other
year
between
1986
and
1992.
In
1989,
spot
densities
were
less
than
10%
of
their
1995
values
at
Ocracoke
Inlet
(
27
per
100
m3).
Flounder
densities
at
any
month
were
low
during
1988­
1989
(<
1
per
l00
m3)
for
either
species.
Southern
flounder
and
pinfish
were
taken
in
1988­
1989
only
at
Ocracoke
Inlet.

SIZE
For
all
species,
significant
differences
in
body
size
occurred
between
inlets
on
many
sampling
dates
(
Fig.
5:
Mean
standard
lenght
of
six
selected
species
of
fish
larvae
at
Oregon
Inlet
and
Ocracoke
Inlet,
North
Carolina
during
the
1994­
1995
larval
fish
immigration
period.).
Average
lengths
of
Atlantic
menhaden
at
Oregon
Inlet
decreased
in
length
during
November
and
then
rapidly
increased
by
about
10
mm
in
mid­
December.
Increasing
density
and
decreasing
size
of
Atlantic
menhaden
larvae
in
early
November
at
Oregon
Inlet
indicated
that
spawning
schools
moving
south
for
the
winter
were
approaching
the
vicinity
of
the
inlet.
At
Ocracoke
larvae
increased
from
about
17
mm
in
early
December
to
27
mm
by
early
January.
During
the
remainder
of
winter,
25­
28
mm
Atlantic
menhaden
were
caught
at
both
inlets
until
the
end
of
the
season
at
Ocracoke
when
the
size
of
larvae
decreased
to
as
small
as
10
mm.
These
small
menhaden
in
April
probably
resulted
from
spawning
south
of
Ocracoke
Inlet
by
northerly
moving
adults.
Small
Atlantic
menhaden
were
not
collected
at
Oregon
Inlet
or
at
Beaufort
Inlet
in
April.
Atlantic
croaker
increased
>
50%
in
length
at
both
inlets
between
late
October
and
late
December.
Spawning
of
Atlantic
croaker
near
Cape
Hatteras
begins
at
least
by
early
September,
peaks
in
October,
and
is
reduced
by
late
December
with
perhaps
another
peak
in
the
spring
(
Morse
1980).
Near
Beaufort
Inlet,
in
Onslow
Bay,
Atlantic
croaker
were
reported
to
spawn
between
mid
September
and
late
February,
with
the
majority
of
spawning
between
late
September
through
November
(
Warlen
1982).
Evidence
of
summer
spawning
was
presented
by
Hettler
and
Barker
(
1993)
who
caught
7
mm
Atlantic
croaker
at
both
inlets
in
late
August
1989.
Atlantic
croaker
this
size
are
probably
about
30­
days
old
(
Warlen
1982).
In
April
at
Ocracoke
Inlet,
the
size
of
croaker
dropped
to
less
than
10
mm
due
possibly
to
inshore
spawning.
The
corresponding
density
data,
however,
did
not
indicate
the
arrival
of
significant
numbers
of
newly
spawned
larvae.

Spot
increased
in
length
about
2
mm
per
month
after
early
January
and
were
nearly
identical
in
size
at
both
inlets.
At
Oregon
Inlet
no
further
increase
in
length
was
noted
until
mid­
March,
when
a
few
early
juveniles
(>
17
mm)
were
caught.
It
is
difficult
to
determine
if
these
juveniles
had
just
entered
following
ocean
transport,
or
were
established
residents
in
the
inlet
or
nearby
estuary.
Juvenile
spot
(
20­
26
mm)
have
been
collected
in
that
inlet
in
May
and
June
1989
(
Hettler
and
Barker
1993).
Spot
size
data
before
January
and
after
late
March
are
probably
not
useful,
as
few
larvae
were
caught.

The
mean
lengths
of
pinfish
and
both
species
of
flounders
increased
during
the
sampling
period.
Pinfish
were
typically
about
1
mm
smaller
at
Ocracoke
than
at
Oregon
Inlet
and
showed
a
slight
increase
in
average
size
at
both
inlets
from
December
to
February.
After
January,
few
pinfish
were
caught
at
Oregon
Inlet.
The
average
lengths
of
both
species
of
flounder
at
both
inlets
increased
about
2
mm
from
December
to
February.
In
mid­
March
at
Ocracoke
when
densities
of
southern
flounder
were
highest,
this
species
was
about
13
mm.
When
summer
flounder
peaked
in
density
at
Oregon
Inlet
in
mid­
December,
they
also
averaged
13
mm.

CONCLUSIONS
From
these
quasi­
synoptic
weekly
abundance
and
size
estimates
of
the
winterimmigrating
marine
fish
larvae
at
two
major
inlets
to
Pamlico
Sound,
it
appears
that
Oregon
Inlet
imported
larger­
sized
individuals
and
higher
densities
of
Atlantic
menhaden,
Atlantic
croaker,
and
summer
flounder
(
important
commercial
species)
significantly
earlier
than
at
Ocracoke.
In
winters
with
mild
temperatures,
cohorts
of
older,
larger
larvae
that
establish
in
the
nursery
areas
within
Pamlico
Sound
early
in
the
season
may
have
a
survival
advantage
over
cohorts
of
larvae
entering
later
through
either
inlet;
in
severe
winters
the
converse
would
apply
as
inferred
by
Hoss
et
al.
(
1988).

The
relative
value
of
each
inlet
as
a
larval
pathway
for
future
juvenile
production
and
recruitment
into
the
fisheries
cannot
be
extrapolated
from
these
data
without
comparing
analyses
of
the
daily
age
structure
of
immigrating
larvae
with
juveniles
emigrating
Pamlico
Sound
nurseries.
Towards
this
goal,
larval
specimens
fumished
from
this
study
are
now
undergoing
age
and
growth
analyses:
Atlantic
menhaden
(
J.
Rice,
North
Carolina
State
University);
Atlantic
croaker
and
spot
(
C.
Jones,
Old
Dominion
University).
In
the
mean
time,
the
density
data
provided
above
should
be
useful
in
evaluating
the
effects
of
any
future
anthropogenic
modifications
(
e.
g.,
jetties)
to
Oregon
or
Ocracoke
inlets
on
immigrating
fish
larvae.

ACKNOWLEDGEMENTS
­
I
thank
P.
Crumley,
D.
Fuss,
M.
Greene,
D.
Hoss,
M.
Johnson,
C.
Lund,
R.
Robbins,
L.
Settle,
D.
Peters,
H.
Walsh,
and
S.
Warlen
for
assistance
with
sampling.
Larval
fish
processing
was
done
by
M.
Greene
and
H.
Walsh.
Early
drafts
of
the
manuscript
were
reviewed
by
D.
Ahrenholz,
D.
Peters,
and
A.
Powell
of
the
Beaufort
Laboratory
and
J.
Rice,
North
Carolina
State
University.
Support
was
provided
by
the
National
Oceanic
and
Atmospheric
Administration's
Coastal
Ocean
Program
/
Coastal
Fisheries
Ecosystems
Studies.

LITERATURE
CITED
Burke,
J.
S.,
J.
M.
Miller,
and
D.
E.
Hoss.
1991.
Immigration
and
settlement
pattem
of
Paralichthys
dentatus
and
P.
lethostigma
in
an
estuarine
nursery
ground,
North
Carolina.
Netherlands
Journal
of
Sea
Research
27:
393­
405.

Fahay,
M.
P.
1983.
Guide
to
the
early
stages
of
marine
fishes
occurring
in
the
western
North
Atlantic
Ocean,
Cape
Hatteras
to
the
southern
Scotian
Shelf.
Journal
of
Northwest
Atlantic
Fishery
Science
4:
1­
423.

Epperly,
S.
P.
and
S.
W.
Ross.
1986.
Characterization
of
the
North
Carolina
Pamlico­
Albemarle
estuarine
complex.
NOAA
Technical
Memorandum
NMFS­
SEFC­
175.

Friedland,
K.
D.,
D.
W.
Ahrenholz,
and
J.
F.
Guthrie.
1996.
Formation
and
seasonal
evolution
of
Atlantic
menhaden
juvenile
nurseries
in
coastal
estuaries.
Estuaries
19:
105­
114.

Hettler,
W.
E,
Jr.,
and
D.
L.
Barker.
1993.
Distribution
and
abundance
of
larval
fishes
at
two
North
Carolina
inlets.
Estuarine,
Coastal
and
Shelf
Science
37:
161­
179.

Hettler,
W.
F.,
Jr.,
D.
S.
Peters,
D.
R.
Colby,
and
E.
H.
Laban.
1997.
Daily
variability
in
abundance
of
larval
fishes
at
Beaufort
Inlet.
Fishery
Bulletin
95:
477­
493.

Hoss,
D.
E.,
L.
Coston­
Clements,
D.
S.
Peters,
and
P.
A.
Tester.
1988.
Metabolic
responses
of
spot,
Leiostomus
xanthurus,
and
Atlantic
croaker,
Micropogonias
undulatus,
larvae
to
cold
temperatures
encountered
following
recruitment
to
estuaries.
Fishery
Bulletin
86:
483­
488.

Kendall,
A.
W.,
Jr.,
and
J.
W.
Reintjes.
1974.
Geographic
and
hydrographic
distribution
of
Atlantic
menhaden
eggs
and
larvae
along
the
middle
Atlantic
coast
from
RV
Dolphin
cruises,
1965­
66.
Fishery
Bulletin
73:
317­
335.

Lewis,
R.
M.
1966.
Effects
of
salinity
and
temperature
on
survival
and
development
of
larval
Atlantic
menhaden,
Brevoortia
tyrannus.
Transactions
of
the
American
Fisheries
Society
95:
423­
426.
Miller,
J.
M.,
J.
P.
Reed,
and
L.
J.
Pietrafesa.
1984.
Patterns,
mechanisms
and
approaches
to
the
study
of
migrations
of
estuarine­
dependent
fish
larvae
and
juveniles.
Mechanisms
of
migrations
in
fishes,
pages
209­
225
in
J.
D.
McCleve,
G.
P.
Arnold,
J.
J.
Dodson,
and
W.
H.
Neill,
(
editors).
Plenum,
New
York,
New
York.

Morse,
W.
A.
1980.
Maturity,
spawning,
and
fecundity
of
Atlantic
croaker,
Micropogonias
undulatus,
occurring
north
of
Cape
Hatteras,
North
Carolina.
Fishery
Bulletin
78:
190­
195.

Warlen,
S.
M.
1982.
Age
and
growth
of
larvae
and
spawning
time
of
Atlantic
croaker
in
North
Carolina.
Proceedings
of
the
Annual
Conference
of
the
Southeastern
Association
of
Fish
and
Wildlife
Agencies
34:
204­
214.

Warlen,
S.
M.
1994.
Spawning
time
and
recruitment
dynamics
of
larval
Atlantic
menhaden,
Brevoortia
tyrannus,
into
a
North
Carolina
estuary.
Fishery
Bulletin
92:
420­
433.

APPENDIX
Fig.
1.
Study
location.

Fig.
2.
Mean
water
column
temperature
and
salinity
at
Oregon
Inlet
(
solid
line,
squares)
and
Ocracoke
Inlet
(
dashed
line,
triangles),
North
Carolina,
for
each
weekly
sampling
trip
during
the
1994­
95
larval
fish
immigration
period.
Solid
symbols
indicate
ebb
tide
samples;
open
symbols
indicate
flood
tide
samples.

Fig.
3.
Difference
(
anomaly)
between
the
surface
and
the
bottom
temperature
and
salinity
at
Oregon
Inlet
(
solid
line,
squares)
and
Ocracoke
Inlet
(
dashed
line,
triangles),
North
Carolina,
during
the
1994­
95
larval
fish
immigration
period.
Positive
values
indicate
warmer
or
more
saline
water
at
the
surface;
negative
values
indicate
warmer
or
more
saline
at
the
bottom.
Solid
symbols
indicate
ebb
tide
sampling;
open
symbols
indicate
flood
tide
sampling.

Fig.
4.
Mean
densities
of
six
selected
species
of
fish
larvae
at
Oregon
Inlet
(
solid
line)
and
Ocracoke
Inlet
(
dashed
line),
North
Carolina,
during
the
1994­
95
larval
fish
immigration
period.
Error
bars
equal
1
standard
error.

Fig.
5.
Mean
standard
length
of
six
selected
species
of
fish
larvae
at
Oregon
Inlet
(
solid
line)
and
Ocracoke
Inlet
(
dashed
line),
North
Carolina,
during
the
1994­
95
larval
fish
immigration
period.
Error
bars
equal
+
1
standard
error.

Received
8
December
1996
Accepted
25
February
1997
Correct
Citation:
Hettler,
William
F.,
Jr.
1998.
Abundance
And
Size
Of
Dominant
Winter­
Immigrating
Fish
Larvae
At
Two
Inlets
Into
Pamlico
Sound,
North
Carolina.
Brimleyana
25:
144­
155.