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CA
LIF
OR
NIA
FIS
H A
ND
GA
ME
C
allto
rnia
Fish
and
Gam
e 90
(3):1
40-1
54
2004
CU
RR
EN
T S
TA
TU
S O
F S
OU
THE
RN
ST
EE
LHE
AD
1 R
AIN
BO
W T
RO
UT
IN S
AN
MA
TE
0 C
RE
EK
, CA
LIF
OR
NIA
TIM
E. H
OV
EY
C
alifo
rnia
Dep
artm
ent o
f F
ish
and
Gam
e 49
49 V
iew
ridge
Ave
nue
San
Die
go, C
A 9
2123
The
dis
cove
ry o
f a s
mall
popula
tion (
e70 in
div
idu
als
) of
south
ern
st
eelh
ead tr
out, O
nco
rhyn
chus
myk
iss
in S
an M
ate
o C
reek
(S
MC
) and
De
vil C
anyo
nC
reek (
DC
C),
asm
allt
rib
uta
ryto
SM
C, i
n San
Die
goC
ounty
, C
alif
orn
ia in
the s
pri
ng
199
9 re
pre
sents
the fi
rst m
ultip
le re
cord
acc
ount
oft
rou
t in
the
cre
eki
n o
ver5
0 y
ears
. Fro
m A
ugust
1999 to
Dec
embe
rZO
O3,
th
e C
alif
orn
ia D
epart
ment o
f F
ish
and G
ame
(Depart
ment)
conduct
ed a
to
talo
f45
surv
eys
alo
ng
both
creeks
tom
on
itort
he
sta
tuso
fth
etr
ou
t. D
ata
on
tro
ut a
bundance
,age a
nal
ysis
,wat
erte
mp
erat
ure
,sp
awn
ing
beh
avio
r a
nd
ge
ne
tica
na
lysi
swe
reco
llect
ed
du
rin
g th
esu
~ey
s.W
eob
serv
edth
at
tro
utn
urn
be
rso
nS
MC
began to
de
clin
esh
ort
ly a
fte
rth
esu
rve
ys b
eg
an
in
1999
, and th
at t
he la
st tr
ou
twa
s obse
rved in
Au
gu
st 2
000.
Juve
nile
tro
ut
were
dis
cove
red o
n D
CC
in
May
and J
uly
200
0 a
nd
matu
ring fis
h w
ere
con
tinu
ally
monito
red o
n D
CC
thro
ugh 2
001
an
d 2
002,
with
no
new
re
cruitm
ent r
eco
rded d
uri
ng
that t
ime.
Asi
ng
lea
du
lt h
old
ove
rtro
ut(
DC
2)
was
obse
rved o
n th
e c
onflu
ence
as
rece
ntly
as
Dece
mber o
f 200
3. W
ater
te
mpera
ture
data
co
llect
ed
on
bo
th c
reeks
suggest
ed
that
annual
tem
pera
ture
pro
file
sare
more
sla
ble
an
d s
uita
ble
fGso
uth
ern
steelh
ead
surv
ival i
n D
CC
than in
SM
C.W
eass
um
eth
atth
isd
iffe
ren
ceen
han
cest
rou
t su
rviv
al
in D
CC
. S
paw
nin
g b
ehavi
or
was
de
scri
be
d o
n t
wo d
iffere
nt
occ
asi
ons
on
DC
C,
ind
ica
ting
the p
ote
ntia
l fo
r re
sid
en
t re
pro
duct
ion.
How
eve
r, n
oa
ctu
als
pa
wn
ing
was
eve
r re
cord
ed
on
SM
Co
r DC
C. G
enetic
and a
ge a
naly
sis
on
speci
mens
colle
cted in
199
9 a
nd
200
0 est
ablis
hed
that a
t least
two p
airs
of anadro
mous
steelh
ead e
nte
red th
e d
rain
age in
19
97 to
spaw
n a
nd
that s
ucc
ess
ful,
resi
dent r
ep
rod
uct
ion
(FI)
occ
urr
ed
in D
CC
in
200
0.
Oto
lith
age
analy
sis
of
a s
ingle
ad
ult in
div
idu
al (
DC
l)
colle
cte
din
DC
Cin
2002 co
nfirm
ed
that m
atu
rin
g,s
ew
nd
genera
tion tr
out
(FZ
) occ
upie
d t
ha
t tr
ibuta
ry,
alb
eit
in e
xtre
mely
sm
all
num
bem
(C
8
indiv
iduals
). T
hen
um
ber
son
DC
Cco
nti
nu
edto
dro
pu
nti
lon
lyas
ing
lead
ult
tr
ou
t (33
7 m
m T
L) w
as
obse
rved d
uri
ng
a s
urv
ey
in D
ece
mber 2
003.
The
hig
her w
ate
r tem
pera
ture
and p
rese
nce
of n
on-n
atlv
e fl
sh s
peci
es
likely
co
ntr
ibu
ted
toth
eext
irp
atio
no
f ad
ultt
rou
t on S
MC
in
2000
. Conve
rsely
, the
lack
of
non-n
ativ
e fi
sh a
nd th
e m
ore
sta
ble
wate
r te
mpera
ture
in
DC
C
enable
d tr
ou
t to
su
rviv
e o
n th
e t
rib
uta
ry u
ntil t
he l
ow
wate
r co
nd
itio
ns
impact
ed th
eir n
um
bers
consi
dera
bly
.
INTR
OD
UC
TIO
N
Sou
ther
n st
eelh
ead
trou
t his
torica
lly o
ccur
red
from
San
to D
om
ingo R
iver
in
nort
hern
Baj
a C
alif
om
iato
Malib
u C
reek
, Calif
orn
ia. H
isto
ricre
cord
sals
o sh
ow th
at in
140
the
earl
y 19
00's
, San
Mat
eo C
reek
may
hav
e be
enon
e of
the
mos
t im
port
ant s
outh
ern
stee
lhea
d sp
awni
ng st
ream
son
the
sout
h co
ast (
USF
WS
Rep
ort 1
998'
). A
t the
irpe
ak,
the
San
Mat
eo C
reek
ste
elhe
ad r
uns
wer
e re
cord
ed a
s la
rge
and
cons
iste
nt, w
ith t
he
fish
doc
umen
ted
toat
tain
a la
rger
size
than
thei
rrel
ativ
es to
then
orth
. Des
pite
the
high
nu
mbe
rs r
ecor
ded
in th
e ea
rly
part
of
the
Cen
tury
, tro
ut s
ight
ings
dro
pped
off
in th
e 19
40's
and
the
1950
's a
nd c
onsi
sten
t tro
ut a
bund
ance
has
not
bee
n pr
esen
t with
in S
an
Mat
eoC
reek
orso
utho
fMal
ibuC
reek
in t
hela
st 5
0 ye
ars (
US
FW
S R
epor
t 1 99
S2). T
he
last
reco
rded
sig
htin
g of
mul
tiple
age
-cla
sses
of
sout
hern
ste
elhe
ad o
n SM
C w
as in
19
50 du
ring
a D
ep
ah
en
t str
eam
sur
vey.
Sin
ce th
en, o
nly
anec
dota
l obs
erva
tions
of
trou
t on
the
cree
k ha
ve b
een
reco
rded
. Si
nce t
hat t
ime,
inco
nsis
tent
wat
er a
vaila
bilit
y du
e to
an
incr
ease
in g
roun
d w
ater
pu
mpi
ng b
egin
ning
in th
e la
te 1
950'
s an
d th
e ne
gativ
e in
flue
nce o
f non
nativ
e pl
ants
, (T
amar
isk
sp.),
beg
an t
o co
ntri
bute
to t
he a
ltera
tion
of s
trea
m h
abita
t with
in S
MC
. C
ritic
al s
trea
m s
truc
ture
s fo
r tro
ut re
prod
uctio
n, s
uch
as ri
ffle
s an
d gr
avel
bed
s no
w
sitd
ry an
duse
less
due
toal
tere
d fl
ow d
ynam
ics.
Inco
nsis
tent
wat
erle
vels
also
redu
ces
thea
mou
nt o
ftim
e SM
C re
mai
ns o
pen
to th
e oc
ean,
furt
herl
imit
ingu
pstr
cam
mig
mti
on
of s
outh
ern
stee
lhea
d, a
s w
ell a
s do
wns
trea
m e
mig
ratio
n of
resi
dent
fis
h.
Furt
her
effe
ctin
g tr
out p
rese
nce
was
the
intr
oduc
tion
of n
onna
tive
terr
estr
ial a
nd
aqua
tic s
peci
es (
larg
emou
th b
ass,
Mic
ropt
erns
sal
moi
des,
grc
cn s
unfi
sh, L
epom
is
cyan
ellu
s, b
lueg
ill, L
epom
is m
acro
chir
us, b
lack
bul
lhea
d, A
mei
unrs
mel
as, m
osqu
ito
fish
, G
ambu
sia
afln
is,
swam
p cr
ayfi
sh,
Pro
cam
baru
s cl
arki
i, an
d bu
llfro
g, R
ana
cate
sbei
ana)
into
San
Mat
eo C
reek
. The
sc sp
ccie
s hav
e be
en d
ocum
ente
d to
incr
ease
co
mpe
titiv
e an
dpre
dato
ry im
pact
s on
seas
onal
salm
onid
runs
, as w
ell a
s res
iden
t tro
ut
popu
latio
ns. S
teel
head
that
wer
e fo
rtun
ate
enou
gh to
find
per
iodi
c av
aila
ble
wat
er to
m
igra
te u
pstr
eam
, oft
en f
ound
thei
r sp
awni
ng g
roun
ds in
fcst
ed w
ith n
onna
tive
fish
sp
ecie
s, h
eavi
ly i
mpa
ctin
g re
prod
uctiv
e su
cces
s.
Due
to th
ese
two
fact
ors (
alte
red
habi
tat a
nd th
e int
rodu
ctio
n of
aqua
tic,
non
nativ
e sp
ecie
s), i
t was
gen
eral
ly c
oncl
uded
that
sou
lhem
stee
lhea
d tr
out w
ere
extin
ct s
outh
of
Mal
ibuC
reek
, Cal
ifom
ia.
The
dec
line
in q
ualit
y, s
outh
ern
stee
lhea
d ha
bita
t an
d th
e ab
senc
e of
ste
elhe
ad
trou
t insouthemCalifornia,pro~nptedtheNational Mar
ineF
ishe
ries
Ser
vice
(NM
FS)
to li
st s
outh
ern
Cal
ifor
nia'
s E
volu
tiona
rily
Sig
nifi
cant
Uni
t (E
SU)
for
anad
rom
ous
stee
lhea
d as
an en
dang
ered
spec
ies i
n 19
97 (F
eder
al R
egis
try
62 F
R43
937)
. Thi
s lis
ting,
ho
wev
er, d
esig
nate
d th
e cu
rren
t sou
them
ES
U b
ound
ary
as M
alib
u C
reek
, Cal
ifor
nia
and
prot
ectio
n w
as e
xclu
ded
for a
ll po
tent
ial
wat
erw
ays
sout
h of
that
bo
un
d~
. T
he d
isco
very
of
sout
hern
ste
elhe
adlr
ainb
ow t
rout
, O
ncor
hync
hus
myk
iss,
on
SM
C an
dDev
il C
anyo
n C
reek
(DC
C) a
smal
l tri
buta
ly to
SM
C, i
nSan
Die
go C
ount
y,
'U.S
. Fi
sh a
nd W
ildlif
e Se
rvic
e. 1
998,
Sou
ther
n St
eelh
ead
Onc
orhy
nchu
s m
ykiss
Hab
itat
Suita
bilit
ysur
veyo
Clh
e San
laM
arga
ritaR
iver
, San
Mat
eo an
dSan
Ono
6eC
reek
sonM
arin
e C
orps
Bas
e, C
amp
Pend
leto
n. C
oast
al C
alifo
mia
Fish
and
Wild
life O
ffic
e, A
rcat
a, C
A.
Prep
ared
for A
ssis
tant
Chi
ef o
f Sta
ff, E
nviro
nmen
tal S
ecur
ity.
'U.S
. Fish
and
Wild
life
Serv
ice.
199
5, S
anta
Mar
gari
tn R
iver
and
San
Mat
eu C
reek
Sal
mon
id
Stud
y. P
rogr
ess
Rep
ort
prep
ared
for
Cam
p Pe
ndle
ton
Mar
ine
Cor
ps. B
ase,
Jan
uary
- Se
ptem
ber 1
995.
Coa
stal
Cal
iforn
ia F
ish a
nd W
ildlif
e Off
ice.
Arc
ata,
CA
.
142
CA
LIF
OR
NIA
FIS
H A
ND
GA
ME
Cal
ifor
nia d
urin
g sp
ring
199
9, es
tabl
ishe
d a
need
to e
xten
d th
e ne
wly
des
igna
tedE
SU
bo
unda
ry. T
he p
opul
atio
n si
ze, t
houg
h ne
ver
accu
rate
ly d
eter
min
ed, w
as e
xtre
mel
y sm
all (<70individuals).whichlimitedthenumberofsamplesthatcouldbecollected(l0
adul
ts in
199
9 an
d 5
juve
nile
s in
200
0) f
or a
naly
sis.
Des
pite
this
, suc
cess
ful a
naly
sis
was
con
duct
ed o
n ge
netic
s, a
ge, a
nd o
tolit
h m
icro
chem
ishy
for
the
SMC
pop
ulat
ion.
G
enet
ic a
naly
sis
cond
ucte
d on
a f
in-c
lip c
olle
cted
fro
m a
sin
gle
adul
t in
199
9 (S
M41
2199
F) r
evea
led
that
the
spe
cim
en c
anie
d a
uniq
ue h
aplo
type
tha
t is
mos
t co
mm
only
fou
nd in
sou
ther
n C
alif
orni
a st
eelh
ead
and
has
neve
r be
en s
een
in a
ny
batcherypopulationofsteelheadorrainbowtrout(Nielsenetal. 19
94).
Thi
sinf
orm
atio
n co
nfir
med
tha
t th
e tr
out
occu
pyin
g SM
C w
ere
wild
fis
h.
Oto
lith
mic
roch
emis
hy
perf
orm
edon
asin
gles
peci
men
col
lect
ed6o
m S
MC
in 1999confirmedthattbeexarnined
fish
was
the
pro
geny
of
an a
nadr
omou
s fe
mal
e st
eelh
ead
(CD
FG s
teel
head
rep
ort,
2000
3; R
iern
an e
ta!.
1994
) and
that
the
coho
rts o
ccup
ying
SM
C w
ere
the
offs
prin
g of
oc
ean-
goin
g ad
ults
. A
ge a
naly
sis
of a
sin
gle
otol
ith in
dica
ted
that
the
fish
wer
e 2+
ye
arso
fage
whe
ncol
lect
edin
199
9. B
ack
calc
ulat
ing
6o
m th
e ag
eat d
isco
very
,it w
as
conf
umed
that
the
anad
rom
ons
stee
lhea
d ad
ults
mos
t lik
ely
ente
red
the
San
Mat
eo
drai
nage
to s
paw
n du
ring
a h
igh
wat
er p
erio
d in
ear
ly s
prin
g 19
97.
Thi
s in
form
atio
n an
d ad
ditio
nal
mon
itori
ne o
bser
vatio
ns w
ere
com
bine
d an
d .,
subm
ittcdasanorig~nalrcp~~ntothcNat~onal
Man
neF
~she
nesS
erv~
ct.(
NM
FS)
hy
the
Cal
ifor
nia D
span
rncn
t ofF
lsh
andG
arne
(Dep
artm
ent)
in F
cbm
ary
2000
. 11 w
asho
ped
that
this
rece
nt in
form
atio
n on
the
new
ly d
isco
vere
d po
pula
tion
ofso
uthe
m s
teel
head
tr
out i
n SM
C w
ould
requ
ire
NM
FS to
re-
eval
uate
the
rece
ntly
des
igna
ted
geog
raph
ic
boun
dary
of t
he e
volu
tiona
ry s
igni
fica
nt u
nit (
ESU
) for
this
spe
cies
. Due
to th
e ra
rity
of
this
occ
urre
nce,
the
Dep
artm
ent a
lso
initi
ated
a m
onito
ring
pro
gram
to
hack
the
stat
us o
f the
ste
elhe
adir
ainb
ow tr
out p
opul
atio
n on
SM
C im
med
iate
ly fo
llow
ing
the
1999
disc
over
y. C
ontin
uedm
onito
ring
bega
n in
Aug
usto
f 19
99 an
d ov
erth
e fol
low
ing
4-ye
ar p
erio
d, a
dditi
onal
inf
orm
atio
n on
gen
etic
s, a
ge a
t gr
owth
, ho
ut b
ehav
ior,
te
mpe
ratu
re c
ondi
tions
and
pop
ulat
ion
stat
us w
as c
olle
cted
. T
he o
bjec
tives
of t
his
stud
y ar
e to
: 1)
des
crib
e th
emon
itor
ing
cond
ucte
d an
d da
ta
gath
ered
on
the
drai
nage
sin
ce th
e re
-dis
cove
ry in
199
9; an
d 2)
to il
lush
ate t
he f
acto
rs
affe
ctin
g th
e su
rviv
al a
nd c
urre
nt st
atus
oft
he so
uthe
m st
eelh
ead/
rain
bow
trou
t in
San
Mat
eo a
nd D
evil
Can
yon
cree
ks.
ME
TH
OD
S A
ND
MA
TE
RIA
LS
A to
tal o
f45
stre
am su
rvey
s wer
e co
nduc
ted
by th
e D
epar
tmen
t fro
m A
ugus
t 199
9 to
Dec
ernb
er20
03.
Sw
eysw
erec
ondu
cted
by D
epar
tmen
tper
sonn
elan
dvol
unte
ers,
an
d st
arte
d at
the
Uni
ted
Stat
es G
eolo
gica
l Sur
vey
(USG
S N
o. 1
1046
300)
gau
ging
st
atio
n on
SM
C to
the
Dev
il C
anyo
n C
reek
con
flue
nce
and
incl
uded
the
entir
e D
evil
Can
yon
Cre
ek d
rain
age.
Thr
ee la
rge
pool
s lo
cate
d on
SM
C, P
ools
1.2
and
3, (
Fig.
1)
'Cal
ifom
iaD
epar
tmen
t of F
ish a
nd G
ame (
CD
FG) 2
000.
Ste
elhe
ad ra
inbo
w tr
out i
n Sa
nMat
eo
Cre
ek, S
an D
iego
Cou
nty,
Cal
ifor
nia.
Rep
ort s
ubm
ined
to th
e N
atio
nal M
arin
e Fi
sher
ies
Figu
re 1
. Map
of s
urve
y ar
ea s
how
iog
Pool
1. 2
and
3, t
empe
ratu
re p
robe
dep
loym
ent a
reas
, ga
ugin
g st
atio
n, a
nd tr
out l
ocat
ions
.
rem
aine
d is
olat
ed f
or m
uch
of t
he s
urve
y pe
riod
and
was
exa
min
ed d
urin
g ea
ch
depa
rtm
ent s
urve
y. A
n ad
ditio
nal 3
.4 km o
f San
Mat
eo C
reek
abo
veth
e Dev
il C
anyo
n C
reek
con
flue
nce
wer
e in
freq
uent
ly s
urve
yed.
Su
rvey
tec
hniq
ues
used
wer
e dr
aina
ge m
appi
ng,
back
pac
k el
ectr
o-sh
ocki
ng
(Sm
ith-R
oot 1
2-B
), sn
orke
ling,
sei
ning
, and
pas
sive
obs
erva
tion.
D
rain
age
map
ping
invo
lved
hik
ing
the
DC
C d
rain
age
to e
valu
ate
habi
tat a
nd to
id
entif
y in
divi
dual
trou
t lo
catio
ns.
Dat
a w
as c
olle
cted
on
fish
bar
rier
s, q
ualit
y of
ha
bita
t, an
d fi
sh p
rese
nce.
E
lect
ro-s
hock
ing
surv
eys w
ere
cond
ucte
d fo
r exo
tic sp
ecie
s rem
oval
and
juve
nile
tr
out d
etec
tion
in a
reas
whe
re se
ioin
gwas
not p
ossi
ble.
Dat
awer
e co
llec
tedo
nspe
cies
ob
serv
ed, w
ater
tem
pera
ture
, and
eff
ort (
seco
nds)
for e
ach
elec
tro-
shoc
king
sur
vey.
T
heus
eoft
heba
ck p
acke
lect
ro-s
hock
erw
as li
mit
eddu
ring
the
surv
ey pe
riod
tore
duce
th
e po
ssib
ility
of
inju
ry to
resi
dent
trou
t. Pr
esen
cela
bsen
ce sn
orke
l sur
veys
wer
e co
nduc
ted
in p
oole
d ar
easw
here
eff
ectiv
e se
inin
g was
diff
icul
t and
whe
re el
ectr
o-sh
ocki
ng w
as in
effe
ctiv
e. S
nork
el su
rvey
s wer
e co
nduc
ted
by a
sin
gle
obse
rver
usi
ng a
n un
derw
ater
div
e lig
ht.
Eac
h su
rvey
cov
ered
th
eent
irep
ool a
nd a
ll fi
sh sp
ecie
s wer
e re
cord
ed. W
hen
trou
t wer
e obs
erve
d, si
ze (t
otal
le
ngth
) was
est
imat
ed a
nd o
ver
all h
ealth
ass
esse
d.
144
CA
LIF
OR
NIA
FIS
H A
ND
GA
ME
Tw
odif
fere
nt t
ypes
of s
eine
s wer
e us
ed to
sam
ple
the
drai
nage
: a 3-m be
ach
sein
e an
d a
12-m
pol
e se
ine.
Sei
nes w
ere
used
for
exo
tic
spec
iesr
emov
al a
nd to
det
erm
ine
if tr
out w
ere
pres
ent.
Pass
ivep
rese
ncel
ahse
nce
shor
e obs
erva
tion
s wer
e co
nduc
ted
on se
vera
locc
asio
ns
to r
ecor
d tr
out
sigh
ting
s an
d ab
unda
nce.
D
ata
wer
e co
llect
ed o
n th
e le
ngth
of
obse
rvat
ion
and
the
spec
ies
enco
unte
red.
A
ll tr
out
sigh
ting
s ob
tain
ed b
y pa
ssiv
e sh
ore
obse
rvat
ions
wer
e vi
sual
ly c
onfi
rmed
with
fol
low
-up
snor
kel s
umey
s the
sam
e da
y. A to
tal o
f 15
fin-
clip
s wer
ecol
lect
ed f
orge
neti
cpur
pose
s fro
mM
arch
199
910 J
une
2000
(Tab
le 1
). E
achs
ampl
ecom
pris
ed o
fa I
-cm
squa
repi
eceo
ffin
tiss
ueex
cise
dfro
m
theuppe~~loheofthecaudalfin an
dpla
ced
on fi
lter
pape
rtod
ry. A
lldr
ieds
ampl
esw
ere
placedinsmallenvelopesfora~~alysis.
A si
ngle
gene
tics
ampl
ewas
sent
torm
itoch
ondr
ial
DN
A (
mtD
NA
) an
alys
is i
n 19
99 a
nd v
erif
ied
the
resi
dent
out
as w
ild f
ish.
Thi
s sp
ecim
enis
desi
gnot
edas
SM
4121
99F
inT
able
1. T
here
mai
ning
14 s
ampl
esw
eres
ent
out f
or m
itoc
hond
rial
DN
A (m
tDN
A)
anal
ysis
in M
arch
of 2
001
and
wer
epor
t on
the
find
ings
of
that
ana
lysi
s in
this
stu
dy (
Tab
le 1
).
Thr
ee te
mpe
ratu
re lo
gger
s (t
wo
Ons
et O
ptic
Sto
wA
way
mod
el n
umbe
r WTA
OB
- 05
+37
and
one
Ons
et O
ptic
Sto
wA
way
Tid
bit m
odel
num
ber
TB
132-
05+3
7) w
ere
depl
oyed
(tw
o on
DC
C a
nd o
ne o
n SM
C)
in A
ugus
t 20
01.
Eac
h pr
obe
gath
ered
lc
mpe
rutu
re d
ata
evcr
y 15
mtn
utes
for
n p
cnod
of
o\e
r I
I ~
nott
tl~
r.
I>au
It~
gg-r
No
471213(DC13Jwasdeployed1nasmallpoolatGPSN 53
476
65.M
' 17
454
85on
DC
C.
appr
oxim
atel
y 1.
6 km
iom
SM
C (F
ig. 1
). T
idhi
tdat
alog
gerN
o. 3
6420
3 (D
C03
) w
as
Tab
le 1
. Tro
ut g
enet
ic s
ampl
es c
olle
cted
on
San
Mat
eo C
reek
and
Dev
il C
anyo
n C
reek
Dat
e L
engt
h mm
Col
lect
ion
Dat
e Sa
mpl
e C
olle
cted
T
L
Loca
tion
Ana
lyze
d
SM41
2199
F S
MlF
SM
2F
SM3F
SM
4F
SM5F
SM
6F
SM7F
SM
RF
SM
IlF
SM
15F
SM 1
6F
SM17
F SM
IBI-
SM19
F
Dev
il C
anyo
n Sa
n M
ateo
Cre
ek
San
Mat
eo C
reek
D
evil
Can
yon
San
Mat
eo C
reek
Sa
n M
ateo
Cre
ek
San
Mat
eo C
reek
Sa
n M
ateo
Cre
ek
San
Mat
eo C
reek
Sa
n M
ateo
Cre
ek
Dev
il C
anyo
n D
evil
Can
yon
Dev
il C
anyo
n D
evil
Can
yon
Dev
il C
anyo
n
May
199
9 M
arch
200
1 M
arch
200
1 M
arch
200
1 M
arch
200
1 M
arch
200
1 M
arch
200
1 M
arch
200
1 M
arch
200
1 M
arch
ZOO
1 M
arch
ZOO
1 M
arch
200
1 M
arch
200
1 M
arch
200
1 M
arch
200
1
deployedinala1gerpoolatGPSN33.47453,W 117.45926onDCC,approximately 0
.8
kmfi
omS
MC
(Fig
. 1). DataloggerNo.4712Sh(SM56)wasdeployedinPool3
onS
MC
(F
ig. I
).
A s
ingl
e ad
ult '
out
was
col
lect
ed in
Jun
e 20
02 o
n D
CC
(de
sign
ated
DC
I) a
nd
exam
ined
to
dete
rmin
e ag
e. T
he f
ish
was
wei
ghed
, m
easu
red,
and
dis
sect
ed.
The
sa
gitt
al o
tolit
hs w
ere
rem
oved
, cl
eane
d, a
nd a
ge d
eter
min
atio
n, u
slng
a d
isse
ctin
g sc
ope,
was
con
firm
ed b
y fo
ur re
ader
s (F
ig. 2
).
RE
SU
LTS
Figu
re 2
. O
tolit
h m
icro
grap
h of
trou
t mlle
cled
on
Dev
il C
anyo
n C
reek
in Ju
ne 2
002.
Age
was
de
term
ined
to b
e 2
+ye
ars o
f ag
e. S
peci
men
was
273
mm
TL
. Pho
to b
y R
. Titu
s
146
CA
LIF
OR
NIA
FIS
H A
ND
GA
ME
Obs
erva
tions
dur
ing
the
surv
ey p
erio
d (A
ugus
t 199
9 to
Dec
embe
r 200
3) re
veal
ed
that
the
trou
t loc
ated
in S
MC
dec
lined
innu
mbe
rs, w
ith n
o bo
ut b
eing
obs
erve
d af
ter
Aug
ust2
000.
InM
ay a
ndJu
ly 2
000,
a to
tal o
f22j
uven
ile
hout
,ran
ging
insi
ze f
rom
60-
81 m
mT
L,w
asdi
scov
ered
occu
pyin
gthe
firs
t 1.2
km
ofD
CC
. Con
tinue
dobs
erva
tions
of
juve
nile
trou
tonD
CC
last
ed th
roug
h Se
ptem
ber2
000.
No
juve
nile
trou
twer
e lo
cate
d in
SM
Cdu
ring
thes
uwey
peri
od.
In A
ugus
t200
1, s
ever
alad
ulttr
out (
200-
250m
mT
L)
wer
e ob
serv
ed in
two
sepa
rate
poo
ls o
n D
CC
, app
roxi
mat
ely
0.8
and
1.6 k
m f
rom
the
SMC
con
flue
nce
(Fig
. 1)
. The
se w
ere
assu
med
to b
e co
hort
s oft
hejn
veni
les
foun
d in
20
00.
Obs
erva
tions
of
adul
ts o
ccup
ying
DC
C a
ppro
xim
atel
y 1.
6 km
up f
rom
the
co
nflu
ence
cont
inue
d thr
ough
Dec
embe
r200
3. T
rout
wer
e fre
quen
tly ob
serv
ed in
DC
C
occu
pyin
g po
ols
duri
ng th
e sp
ring
whe
re t
hey
wer
e pr
evio
usly
abs
ent,
indi
catin
g po
ssib
le d
owns
trea
m m
igra
tion.
W
hile
the
age
at s
ize
of th
e ju
veni
les
foun
d on
DC
C c
ould
not
be
conf
irm
ed, t
he
mea
sure
men
tsof
the
indi
vidu
als a
re w
ell w
ithin
them
axim
um fi
rsty
earg
row
th ra
teof
si
ze-a
t-ti
med
atac
olle
cted
by th
eDep
artm
ent o
fkno
wn-
agej
uven
ile
stee
lhea
d tr
out i
n so
uth-
cent
ral a
nd s
outh
ern
Cal
ifor
nia
coas
t (C
DFG
Ste
elhe
adR
epor
t200
0).
Rep
rodu
ctiv
e ac
tivity
was
obs
erve
d on
DC
C in
Aug
ust 2
001
and
Janu
ary
2002
. T
hree
adu
lt tr
out w
ere
obse
rved
par
ticip
atin
g in
bri
ef s
paw
ning
epi
sode
s on
Dev
il C
anyo
nCre
ek, i
n ap
ool a
ppro
xim
atel
y O
.8la
n fr
om th
e S
anM
ateo
Cre
ekco
nflu
ence
. In
divi
dual
s wer
eusi
ng a
cent
ral b
ould
eras
a st
agin
g ar
eaan
d co
nduc
tingr
epro
dnct
ive
post
urin
g di
rect
ly u
pstr
eam
of t
he b
ould
er.
A re
dd h
ad b
een
cons
truc
ted
adja
cent
to
theb
ould
er an
d in
divi
dual
s wer
e obs
erve
d app
roac
hiig
the r
edd
andr
ubbi
ng th
emse
lves
on
theg
rave
l bot
tom
. T
he re
ddw
as ap
prox
imat
ely
45-6
0 cm
in d
ia
me
te
r
asac
ucnl
ar,s
andy
area
whe
real
l the
leaf
litte
r had
bee
neith
erre
mov
ed o
r cov
ered
. One
ob
serv
atio
n w
as r
ecor
ded
whi
le t
he p
ool
was
bei
ng s
nork
eled
and
ano
ther
was
re
cord
ed fr
om a
rock
out
crop
ping
dir
ectly
abo
ve th
e po
ol.
Bot
h ep
isod
es w
ere
brie
f an
d ac
tivity
cea
sed
once
the
obse
rver
s w
ere
dete
cted
by
the
trou
t. W
hile
this
was
en
cour
agin
g,no
actu
al sp
awni
ng w
as o
bser
ved
and
no n
ew re
crui
tmen
t was
docu
men
ted
for2
001
0120
02.
Mito
chon
dria
1 DN
A (m
tDN
A) w
as su
cces
sful
ly ex
trac
ted f
rom
all f
in-c
lip sp
ecim
ens
and
anal
yzed
acc
ordi
ng to
est
ablis
hed
anal
ytic
al m
etho
ds (N
iels
en e
t al.
1997
). F
ive
ofth
e 19
99sa
mpl
es(S
M3,
SM
4, S
M7,
SM8,andSM1l)showedalackofdifferentiation
betw
een
the
trou
t col
lect
ed, i
ndic
atin
g th
at th
ese
fish
wer
e co
hort
s of
the
prev
ious
ly
analyzedSM412199F(Fl)(Fig. 3
). T
here
mai
ning
four
adul
ts (S
M1,
SM
2, S
M5,
and
SM6)
dif
fere
d in
rela
tedn
ess
from
SM
4 12
199
F an
d w
ere
prob
ably
des
cend
ed fr
om a
se
para
te p
air o
f ana
dmm
ous
adul
ts th
at e
nter
ed th
e C
reek
in e
arly
199
7. A
naly
sis
of
the j
uven
ile s
ampl
es s
how
ed th
at th
ree
of th
e fi
sh (S
M15
, SM
16, a
nd S
M18
) wer
e of
di
rect
des
cent
(F2)
from
SM
4121
99F
(Fl)
. T
he re
mai
ning
two
juve
nile
s (S
M17
and
SM
19)
had
very
div
erge
nt h
aplo
type
s, s
ugge
stin
g th
at m
ore
than
one
res
iden
t sp
awni
ngpa
irbr
ed s
ucce
ssfu
lly in
DC
C in
199
9 (N
iels
en a
nd S
age 2
001 '
)(Fi
g. 3
). N
o us
eabl
emat
eria
l was
obt
aine
dfro
m S
M14
andt
hiss
ampl
ewas
excl
uded
from
ana
lysi
s.
The
tem
pera
hlre
prob
esw
erer
ecov
ered
in J
uly
2002
. Allthreeprobessuccessfully
'Nie
lsen
1.L
andG
.K. S
age.
2001
Mic
rosa
telli
tean
d m
tDN
A a
naly
seso
fSan
Mat
eo C
reek
trout
, 20
01. A
pro
gres
s re
port.
17
pp.
~6
6~
luol(e6eule.pxae.3
oele.4 JeS e
ql d
oe
3u
esa
~o
us, D8lO
Nl8lLfdn Le
~o
a3
Le
plA
ese
pln
old
~
0~
13
"
oA
L~
~
I AD
O b
o qsq .enoP
Ioq PIO
lee6 c,,
F e ,o ~
olle
~d
es
qo
a
ql F
OO
L sol uennl z2 oooz at,\
jo )led
s (ecp spu
l su..,-oa w
e1
3 L
oh
e3
(tnea JO U
npe peleno3e) e ,o 6utB
e 84
1
2002 ~
8.
3
~0,4uo3 IIAOO
-0
doale ndoa ~j Bu ,"led
ju B
u~
~o
lt~o
rll panulluo3
~O
OZ
A~ny pue
he
n b
~ >
ee
l3 ~
oh
ue
3
lleo
do paJeno3slp s~ (2,)
~n
o~
t q
ue
hn
l lo a
m6
lletlts \I woz 853.3
UO
K~
IP~
.*a0
PL
~
~a
e,3
oelcw b
es L
O P
ePaIeP
s (1,) I~
OJI ~
ueptse. PIO Jeah,
2 lo u
o~
leln
lod
IleW
S v :6661 .h
a~
nS
eue
~
pua qs!d 30 lue
lup
ed
ec~
Eu!Jnp yes13 o~
e!,q
UES
uo
pe
pa
lap
148
CA
LIF
OR
NIA
FIS
H A
ND
GA
ME
colle
ct~.
ddat
a fcir
the
I I -m
onth
per
iod
ofde
ploy
mcn
i. T
wuo
fthc
pru
bes(
D('
I3 a
nd
DCU3)r
ccor
dedv
crys
imil
ar~a
d1ng
sfro
mAug
ust2
OOl to
hla
rch2
002
They
reco
rded
m
axim
umte
mpe
ratu
reso
f2 1.
8"C
pCl3
)and
23.1
"C(DC03)andminimumtemperatures
of 7
.8'
C a
nd 5
.8'
C, r
espe
ctiv
ely
(Fig
. 4).
The
ran
ges w
ithin
the
first
7 m
onth
s of
depl
oym
entw
erea
lmos
t ide
ntic
al b
etw
een
DC
13 a
ndD
C03
. For
the l
ast 4
mon
ths o
f de
ploy
men
t. DC
13 re
cord
edm
ore c
onsi
sten
ttem
pera
ture
s, w
ith a
ninc
rcas
e fro
m 1
0. lo
*
U
Devil
Cany
on (D
C13)
Temp
eratur
e Pro
file
L
4
I
Devil
Cany
on (D
COJ) T
empe
rature
Profi
le "2
"
30
1
30 Sa
n Mate
o Cree
k (SM56) Te
mpera
ture P
rofile
cu
LU
'1
', 1" ;: $
,, IL
; 1"
D
0
U
I'
I'
I'
I'
I~
I
1 17
01
09~1
lim
i oli
o2
mm2
051112
071
02 09
102
Figu
re 4
. Tem
pera
ture
pro
files
for
Devil
Can
yon
Cre
ek an
d S
an M
ateo
Cre
ek fr
om
Aug
ust 2
001
to J
uly
2002
.
SO
UTH
ER
N S
TEE
LHE
AD
IRA
lNB
OW
TRO
UT I
N S
AN
MA
TE
OC
RE
EK
CA
LIFO
RN
IA
149
C to
18.
lo C
, with
a d
aily
rang
e of
+I-
0.9
' C
(Fi
g. 4
). D
C03
reco
rded
an
incr
ease
in
tem
pera
ture
inth
atsa
mep
erio
d fr
om 1
1.2'
C t
o 18
.9'C
, w
ithd
aily
rang
es o
f+/-
2.5
'C
IFie
.4).
\- --~
,~
T
he S
M56
tem
pera
ture
pro
be re
cord
ed se
vere
tem
pera
ture
vari
atio
ns fr
om A
ugus
t 20
01 to
Dec
embe
r200
1, w
ith re
adin
gs fr
om 2
8.4'
C
to 7
.9"
C, w
ith so
me
daily
rang
es
shif
ting
+/-
7.5
' C
(Fig
. 4).
Beg
inni
ng in
May
200
2, S
M56
reco
rded
a st
eady
incr
ease
in
tem
pera
ture
, with
dai
ly ra
nges
shi
ftin
g +
/- 1
.4'
C a
nd to
ppin
g ou
t at t
ime
ofre
trie
val
at 2
5.X
°C. T
his w
as in
shar
pcon
tras
tto t
he te
mpe
ratu
rem
axim
ums f
orD
C 1
3 and
DC
03
of 1
8.1"
C a
nd 1
8.9'
C, r
espe
ctiv
ely
atti
meo
fpro
be re
trie
val (
Fig.
4).
Age
-at-
grow
th c
alcu
latio
ns w
ere
perf
orm
ed o
n a
sing
le a
dult
fish
(DC
1) c
olle
cted
in
June
2002
. The
fish
was
rece
ntly
expi
reda
ndac
ompl
ete
wor
k-up
was
perf
orm
ed B
oth
the
righ
t and
left
sag
ittal
oto
liths
wer
e re
mov
ed a
nd a
sin
gle
otol
ith w
as a
ged
by fo
ur
read
ers u
sing
a d
isse
ctin
gmic
rosc
ope (
Fig.
2).
The
fish
was
det
erm
ined
to b
e 2+
yea
rs
ofag
e, an
d w
asa2
73-m
mT
Lfe
mal
e(go
nadw
t. 16
.38g
), w
ith a
body
wei
ghto
f213
.5g.
T
he eg
gs o
fthe
fish
wer
e par
tially
hyd
rate
dupo
nrem
oval
and
appe
ared
ofhi
gh q
ualit
y.
Bot
h lo
bes
of th
e ov
arie
s wer
e ru
ptur
ed a
nd th
e st
omac
h w
as e
mpt
y. G
enet
ic m
ater
ial
was
col
lect
ed, b
ut h
as y
et to
be
anal
yzed
. N
o pa
rasi
tes
wer
e ob
serv
ed, i
nter
nally
or
exte
rnal
ly.
A s
ingl
e ad
ult,
hold
over
trou
t (D
C2)
was
obs
erve
d on
the
conf
luen
ce a
s rec
ently
as
Dec
embe
r 200
3. T
his
spec
imen
was
det
erm
ined
to b
e a
F2
hold
over
fish
due
to it
s si
ze, c
olor
atio
n,an
dloc
atio
non t
hecr
eek.
Thi
s obs
e~at
ione
stab
lish
edan
unin
tem
pted
fi
sh p
rese
nce
on th
e dr
aina
ge s
ince
199
7.
DIS
CU
SS
ION
Alm
ost i
mm
edia
tely
follo
win
g th
e di
scov
ery
of s
outh
ern
stee
lhea
d on
San
Mat
eo
Cre
ek, D
epar
tmen
t sur
veys
beg
an to
reco
rd a
decl
ine i
n tr
out n
umbe
rs to
war
ds th
e en
d of
199
9. O
bser
vatio
ns o
ftro
ut in
an
appa
rent
em
acia
ted
cond
ition
str
ongl
y su
gges
ted
that
reso
urce
com
petit
ion
with
exo
tics w
as im
pa
cti
ng
ut i
va
l Add
ition
ally
, the
re
cord
ed w
ater
tem
pera
ture
with
in S
MC
dur
ing
trou
t pre
senc
e st
rong
ly fa
vore
d th
e ex
otic
spe
cies
ove
r th
e tr
out,
and
prob
ably
con
trib
uted
gre
atly
to
thei
r ev
entu
al
extim
atio
n.
The
disc
over
yofj
uven
iletr
out i
nthe
low
erre
ache
s of
DC
C in
May
andJ
uly
of20
00
beca
me
apiv
otal
obs
erva
tion
duri
ng th
e su
rvey
per
iod.
Thi
s illu
stra
ted
that
eve
n w
ith
~ -
infr
eque
nt a
nd i
nter
mitt
ent
stee
lhea
d tr
out
mig
ratio
n in
to t
he d
rain
age,
suc
cess
ful
resi
dent
(F
l) r
epro
duct
ion
coul
d re
sult.
T
hese
obs
erva
tions
als
o co
nfir
med
tha
t ad
equa
te re
side
nt sp
awni
ng h
abita
t doe
s exi
st in
DC
C, a
ndgi
vent
he pr
oper
con
ditio
ns,
resi
dent
spa
wni
ng c
ould
occ
ur. T
his t
ribu
tary
is c
ompl
etel
y fr
ee o
f exo
tic fi
sh sp
ecie
s an
d ho
lds p
rom
isin
g tr
out h
abita
t onl
y a
shor
t dis
tanc
e fr
om th
e SM
C.
Add
ition
ally
, te
mpe
ratu
re s
trat
ifie
dpoo
ls, d
eep
enou
ghan
dcol
d en
ough
to su
ppor
ttro
utye
ar-r
ound
ar
e re
adily
ava
ilabl
e in
the
drai
nage
. T
hege
neti
c an
alys
is w
as c
ruci
al in
not o
nly
esta
blis
hing
thel
inea
ge o
fthe
sam
pled
tr
out w
ithin
the
drai
nage
, but
als
o pr
ovin
g a
conn
ectio
n be
twee
n th
e tr
out l
ocat
ed in
bo
th d
rain
ages
. The
trou
t fir
st a
naly
zed
(SM
412
199F
) was
col
lect
ed in
DC
C a
nd th
e
150
CA
LIF
OR
NIA
FIS
H A
ND
GA
ME
conf
umed
coho
rts(
SM
4, S
M7,
SM
8,an
dSM
ll)w
erea
ll c
olle
cted
inS
MC
,ind
icat
ing
eith
er u
pstt
eam
or d
owns
irea
mm
igra
tion
of t
here
side
nts.
Sin
ce w
e ob
sew
edtr
out i
n de
clin
ing
heal
th, c
o-oc
cuni
ngw
ith
exot
ics i
n SM
C, t
he s
urve
y ob
serv
atio
ns p
rovi
de
stro
ng e
vide
nce t
hat d
owns
trea
m m
igra
tion
of t
he re
side
nts
from
DC
C to
SM
C li
kely
oc
curr
ed.
The
posi
tive
iden
tifi
cati
on of
dire
ct d
esce
nden
ts (S
arnp
lesS
M15
, SM
16, a
ndS
MI 8
) fr
omth
epre
viou
sly
sam
pled
SM
4 12
199F
indi
cate
stha
t thc
trou
lpop
ulat
ion
size
onth
e dr
aina
ge i
s ex
trem
ely
smal
l. T
his
is a
lso
the
firs
t ev
iden
ce s
uppo
rtin
g su
cces
sful
re
pro
du
ctio
nan
dsu
~iva
lofF
2 off
spri
ngfr
omth
is F
1 co
hort
(SM
4 12
1YY
F)(T
ahle
I).
Sin
ce th
e tw
o re
mai
ning
juve
nile
sam
ples
wer
e sh
own
to b
e de
rive
d fr
om a
yet
un
sam
pled
res
iden
t pai
r, w
e co
nclu
ded
that
add
itio
nal,
undo
cum
ente
d re
side
nt f
ish
may
sti
ll o
ccup
y th
e dr
aina
ge, f
urth
er e
leva
ting
pop
ulat
ion
num
bers
. T
he te
mpe
ratu
re d
ata
obta
ined
firo
m th
e pr
obes
cle
arly
sho
ws t
hat D
evil
Can
yon
mai
ntai
nsam
orec
onsi
sten
t and
pref
eren
tial
tem
pera
ture
pro
file
for s
outh
emst
eelh
eadl
ra
inbo
w tr
out s
urvi
val t
han
port
ions
of
San
Mat
eo C
reek
(Fig
. 4).
Sou
them
race
s of
st
eelh
ead
have
evo
lved
a m
uch
high
er t
oler
ance
to
high
tem
pera
ture
s an
d lo
w
diss
olve
d ox
ygen
lev
els
than
is
gene
rall
y th
ough
t su
itab
le f
or ju
veni
le s
alm
onid
s (G
reen
woo
d 19
88),
and
the
pre
ferr
ed w
ater
tem
pera
ture
for
var
ious
lif
e st
ages
of
stee
lhea
d is
wel
ldoc
umen
ted(
Bov
ee 1
978:
Rei
sera
ndB
jom
n 1 9
795:
Bel
l 198
6). W
hile
th
is a
dapt
atio
n to
adv
erse
wat
er c
ondi
tion
s may
ass
ist i
n so
uthe
rn s
tecl
head
surv
ival
, te
mpe
ratu
re st
abil
ity
and
redu
ced
dail
y ra
nge
shif
ts w
ould
bem
ore
favo
rabl
e fo
r tro
ut
occu
pyin
g th
is d
rain
age.
B
oth
SM
C a
nd D
CC
exh
ibit
ide
al s
outh
em s
teel
head
life
his
tory
tem
pera
ture
s (M
cEw
anan
dJac
kson
199
66) fo
rapo
rtio
n of
the y
ear,
but
, dur
ing
the
sum
mer
, sec
tion
s of
the
drai
nage
expe
rien
ce su
rfac
e w
ater
tem
pera
ture
s in
ex
ce~
sof2
6.7
~C
, w
ell a
bove
su
itab
le sa
lmon
id p
refe
renc
e. T
empe
rntu
re st
rati
fica
tion
occ
urs t
hrou
ghou
t the
SM
C
drai
nage
and
has b
een
docu
men
ted
inpo
olso
ccup
ied
by tr
out.
How
ever
, dur
ing
drye
r ye
ars,
poo
l str
dtif
icat
ion
and
surv
ivab
le te
mpe
ratu
res f
or s
alm
onid
s bec
omes
lim
ited
. T
he p
robe
dat
a su
gges
ts th
at th
e ov
er-s
umm
erin
g ha
bita
t ava
ilab
le in
Dev
il C
anyo
n pr
ovid
es a
mor
e st
able
tem
pera
ture
env
iron
men
t fo
r st
eelh
ead
sust
aina
bili
ty a
nd
surv
ival
. T
he c
olle
ctio
n of
the
sing
le d
ead
indi
vidu
al (D
C 1
) on
DC
C d
urin
g th
e su
mm
er o
f 20
02 en
able
dus t
onot
onl
y co
nfn
n th
e ag
eoft
he in
divi
dual
s tha
twer
e cu
rren
tly b
eing
m
onit
ored
on
DC
C, b
ut a
lso
allo
wed
us
to e
xam
ine
the
repr
oduc
tive
sta
tus
of th
e co
llect
ed s
peci
men
. The
fis
h w
as 2
+ ye
ars
of a
ge,
cnn
fmin
g th
at t
he l
ike-
size
d in
divi
dual
s occ
upyi
ng D
CC
wer
e ind
eed
coho
rts o
f the
2000
jwen
ile
grou
p dis
cove
red
in th
e lo
wer
por
tion
oft
he d
rain
age
inM
ay a
nd J
uly
ofth
at y
ear.
Upo
n di
ssec
tion
, no
anom
alie
s wer
e di
scov
ered
. The
wei
ght o
f the
two
ovar
ies m
ade
up o
ver 7
.5%
of t
he
'Rei
ser,
D.W
., an
d T.
C. B
jom
. 197
9. H
abita
trequ
irem
ents
ofan
adro
mou
s sal
mon
ids.
USD
A,
Fore
st S
ervi
ce, P
acifi
c N
onha
est
Fore
st a
nd R
ange
Exp
erim
enta
tion
Stat
ion,
Por
tland
, O
rego
n, G
ener
al T
echn
ical
Rep
ort P
NW
-96,
54
pp.
WcE
wan
,D.a
ndT
.A.Ia
ckso
n 1996.SteeBeadrestorationandmanagementplanforCalifomia.
Cal
iforn
ia D
epar
tmen
t of F
ish
and
Gam
e, S
acra
men
to, C
A.
body
wei
ght
of th
e fi
sh a
nd t
he e
ggs
look
ed t
o be
par
tially
hyd
rate
d in
lif
e. T
his
indi
cate
dtha
t thi
s fis
h co
uld
have
par
tici
pate
din
spaw
ning
activ
ity d
urin
g sp
ring
2002
, gi
ven
the
oppo
rtun
ity. T
here
was
no o
utw
ard
indi
catio
n of
why
the
fish
die
d. H
owev
er,
the
pool
inw
hich
the
fish
was
col
lect
ed, h
ad a
wat
er te
mpe
ratu
re o
f25'
C a
t the
tim
e of
co
llect
ion,
and
it is
like
ly th
e fi
sh s
uccu
mbe
d to
dep
lete
d di
ssol
ved
oxyg
en le
vels
in
the
shal
low
, ove
rhea
ted
pool
. T
he a
dditi
onal
gen
etic
, ag
e, a
nd m
onito
ring
inf
orm
atio
n co
llect
ed d
urin
g th
is
surv
ey p
erio
dcla
rifi
esth
e seq
uenc
eofe
vent
s fo
r the
pop
ulat
iono
f ste
elhe
adhi
nbow
bo
ut o
n th
e Sa
n M
ateo
Dra
inag
e (F
ig. 3
). B
ack
calc
ulat
ions
of t
he in
divi
dual
s age
d in
19
99 co
nfir
m th
at th
e an
adro
mou
s ad
ults
(P
I) en
tere
d th
e dr
aina
ge in
the
earl
y sp
ring
19
97 to
spa
wn.
Gen
etic
ana
lysi
s of
sam
ples
SM
I, S
M2,
SM
5, a
nd S
M6
conf
rm th
e pr
esen
ceof
anad
diti
onal
anad
rom
ousp
airi
nthe
dra
inag
ein
1997
.No f
ish
wer
edet
ecte
d du
ring
aD
epar
hnen
tsur
vey
on S
anM
ateo
Cre
ekin
199
8. In
the
follo
win
g ye
ar, a
smal
l po
pula
tion
of h
out
(FI)
was
dis
cove
red
occu
pyin
g Sa
n M
ateo
Cre
ek.
All
trou
t ob
serv
ed w
ere
of a
sin
gle
age
clas
s (2
+ ye
ars)
, ind
icat
ing
they
wer
e th
e of
fspr
ing
of
a si
ngle
, rep
rodu
ctiv
e ev
ent.
In 2
000,
juve
nile
trou
t (F
2) w
ere
disc
over
ed in
the
low
er
reac
hes o
fDev
il C
anyo
nCre
ek. G
enet
ic a
naly
sisl
inke
dthe
se f
ish
to th
eF1
popu
latio
n,
som
e di
rect
ly d
esce
nded
from
the
firs
t fis
h an
alyz
ed (S
M41
2199
F). T
he p
rese
nce
of
sub-
adul
ts o
n th
e dr
aina
ge in
Nov
embe
r 200
0 su
gges
ts th
at th
ey w
ere
mat
urin
g F
2's.
A
ge a
naly
sis o
f a s
ingl
e ad
ult (
DC
I) c
olle
cted
in Ju
ne 2
002
conf
rms
that
a fe
w o
f the
ad
ult f
ish
curr
ently
occ
upyi
ng D
CC
are
mat
ure
F2'
s (F
ig. 3
). S
urve
ys c
ondu
cted
on
SMC
and
DC
C in
200
1 an
d 20
02 re
veal
ed n
o ne
w re
crui
tmen
t dur
ing
that
tim
e. T
he
disc
over
y of
a 3
.5-y
ear-
old
hold
over
fish
(DC
2) in
DC
C in
Dec
embe
r 200
3 pr
ovid
es
evid
ence
that
ther
e ha
s bee
n an
uni
nter
rupt
ed tr
outp
rese
nce
on th
e dr
aina
ge s
ince
the
anad
rom
ous
adul
ts e
nter
ed S
MC
dur
ing
the
spri
ng o
f 19
97 to
spa
wn.
W
hile
the
timel
ine
oftr
out p
rese
nce
on th
e dr
aina
ge c
anbe
firm
ly es
tabl
ishe
d w
ith
the
evid
ence
gat
here
d du
ring
the
stud
y pe
riod
, som
e qu
estio
n ca
n be
rais
ed o
n w
here
th
e or
igin
al s
teel
head
adu
lts s
paw
ned
in 1
997.
Sur
veys
con
duct
ed in
199
5,19
96, a
nd
1997
byth
eUni
tedS
tate
sFis
hand
Wild
life S
ervi
ce(U
SFW
S) an
daD
epar
tmen
tsur
vey
cond
ucte
d in
199
8 fa
iled
to d
etec
t hou
t on
SM
C.
If a
nadr
omou
s ad
ults
ent
ered
the
drai
nage
and
spa
wne
d in
San
Mat
eo C
reek
in
1997
, you
ng-o
f-th
e-ye
ar in
divi
dual
s sh
ould
hav
e be
en d
etec
ted
in fa
ll 19
97 by
USF
WS
pers
onne
l and
yea
rlm
g in
divi
dual
s sh
ould
hav
e be
ende
tect
ed in
199
8 by
Dep
artm
ent p
erso
nnel
. All
surv
eys i
nclu
dedt
he
stre
am p
ortio
n fr
om th
e U
SGS
gaug
ing
stat
ion
to a
bove
the
DC
C c
onfl
uenc
e, bu
t did
no
t inc
lude
DC
C. S
ince
the
age o
f the
199
9 ind
ivid
uals
has
bee
n co
nfir
med
atZ
+ye
ars
of a
ge a
nd th
e fi
sh w
ere
all c
ohor
ts, t
hey
had
to b
e pr
esen
t on
the
drai
nage
dur
ing
the
1997
and
1998
surv
eys.
Sin
ceth
enps
trea
mm
igra
tion
oppo
~it
iesf
rom
SM
C
toD
CC
ha
ve b
een
extr
emel
y lim
ited
sinc
e 19
99, a
nd h
out w
ere
abse
nt in
SM
C w
hen
thos
e op
port
uniti
es e
xist
ed, w
e ca
n co
nclu
de t
hat
all
trou
t ob
serv
ed d
urin
g th
e or
igin
al
disc
over
y in
199
9, m
igra
ted
dow
nstr
eam
from
DC
C in
to S
MC
. We
can
also
conc
lude
th
at th
e in
divi
dual
s dis
cove
red
in 1
999 w
ere
atte
mpt
ing
to e
mig
rate
out
ofD
CC
at t
he
tim
e of
dis
cove
ry, a
s sev
eral
oft
hem
wer
e ob
serv
ed in
the
silv
ery,
smol
tific
atio
n st
age
whe
n ca
ptur
ed.
The
im
pact
s of
exo
tic f
ish
com
petit
ion
and
pred
atio
n on
nat
ive
fish
is
wel
l
152
CA
LIF
OR
NIA
FIS
H A
ND
GA
ME
docu
men
ted
and
whi
le d
irec
t com
petit
ion
is d
iffi
cult
t~ q
uant
ify,
the
obse
rvat
ion
of
resi
dent
trou
t on
SMC
in a
n un
heal
thy
stat
e co
-occ
unin
g w
ith n
onna
tives
sug
gest
s th
at tr
out s
urvi
val i
ssev
eral
ly h
inde
redb
ythe
con
stan
tpre
senc
eofe
xoti
c fi
shsp
ecie
s.
Exo
tic fi
sh sp
ecie
s (la
rgem
outh
bass
, gre
en su
nfis
h, b
lueg
ill a
ndbl
ack
bullh
ead)
hav
e be
en p
rese
nt in
gre
at n
umbe
rs w
ithin
the
San
Mat
eo C
reek
dra
inag
e fo
r man
y ye
ars
(USF
WS
stat
us re
port
, 19
98; W
oelf
el 1
991 ')
and
hav
e he
en s
how
n to
hav
e a
stro
ng
com
petit
ivee
dgeo
verr
esid
enttr
out.
Gre
en su
nfis
h ha
vebe
en fo
und
to fe
edon
juve
nile
troutandout-competeadultsteelhead f
orbe
nthi
c fo
od(S
wif
t 197
58;G
reen
woo
d 198
8).
Lar
gem
outh
bas
s ta
ke o
ver a
s top
pre
dato
r in
the
habi
tat t
hey
occu
py n
nd c
an d
irec
tly
pred
ate
stee
lhea
d (S
toud
er e
t al.
199
7).
Oth
er st
udie
s hav
e fou
nd th
at co
mpe
titio
n be
twee
n in
trod
uced
, wan
n w
ater
exot
ics
and j
uven
ile s
teel
head
, whe
n w
ater
con
ditio
ns a
re w
arm
, fav
ored
the
exot
ics
(Ree
ves
1985
9). L
ater
stu
dies
infe
rred
that
com
petit
ion
betw
een
exot
ic sp
ecie
s an
d st
eelh
ead
was
lim
iting
prod
uctio
n of
stee
lhea
din
som
e Um
pqua
Riv
er, O
R.tr
ibut
arie
s(Fo
ntai
ne
1988
'").
Whi
le ex
otic
fish
pres
ence
may
hav
epla
ycd
som
crol
e in
ste
elhe
adtr
outd
eclin
e onSMC,thecombinationofahigherwatertemperature a
ndli
mit
edw
ater
supp
ly li
kely
co
ntri
bute
d.
A p
ortio
n of
the
inf
orm
atio
n co
llect
ed d
urin
g th
is 4
-yea
r m
onito
ring
pro
gram
pr
ovid
ed N
MFS
with
eno
ugh
data
to
re-e
valu
ate
the
ESU
geo
gaph
ic u
nit
for
the
enda
nger
ed s
outh
ern
stee
lhea
d tr
out
esta
blis
hed
in 1
997.
On
May
200
2, N
MFS
pu
blis
hed
thei
r fin
al ru
le fo
r the
rang
e ex
tens
ion
for e
ndan
gere
d st
eelh
ead
in s
outh
ern
Cal
ifom
ia. C
iting
thee
xten
sive
mon
itori
ng in
fort
natio
ncol
lect
edby
the
Dep
arhn
enta
nd
then
ew g
enet
ic an
alys
is co
nduc
ted
by D
r. Je
nnif
erN
iels
en, t
heN
MF
S c
oncl
uded
that
th
e 0. m
ykis
s pop
ulat
ion
in S
an M
ateo
Cre
ek is
par
t of t
he li
sted
sou
ther
n C
alif
omia
st
eelh
ead
popu
latio
n an
d w
orth
y of
pro
tect
ion.
Als
o ci
ting
the
San
Mat
eo C
reek
po
pula
tion,
NM
FS d
ecid
edno
t to
delin
eate
a sp
ecif
ic st
ream
as t
he so
uthe
rn h
ound
aty
as it
hadi
n 19
97. I
nste
ad,th
e fi
nalr
ule
stat
es th
atth
elis
tedo
. myk
iss p
opul
atio
n ex
tend
s Fr
omth
e San
taM
aria
Riv
er to
the s
outh
ern
exte
nt o
fits
rang
e. T
hisp
rovi
des a
dditi
onal
pr
otec
tion
for
futu
re d
isco
veri
es w
ithin
the
ent
ire
enda
nger
ed s
outh
em s
teel
head
ra
nge.
The
indi
vidu
als c
urre
ntly
occ
upyi
ng th
e S
an M
ateo
Cre
ek d
rain
age
repr
esen
t th
e so
uthe
rn m
ost d
ocum
ente
d po
pula
tion
of 0
. myk
iss.
It
is c
lear
that
two
defi
nitiv
e pr
oces
ses
com
bine
to in
flue
nce
the
surv
ival
of
the
sout
hern
stee
lhea
d tr
out p
opul
atio
n on
be
San
Mat
eoD
rain
age;
wat
er a
vaila
bilit
y an
d
'Woe
lfel.
D.
1991
. The
rest
orat
ion
of S
an M
ateo
C~
ck
:
A f
easi
bili*
stu
dy fo
r a
sout
hern
C
alifo
mia
stee
lhea
d fi
sher
y. M
S. T
hesi
s, C
alifo
mia
Sta
te U
nive
rsity
, Ful
lerto
n B
Swift
,C.C
.,A.W
. Wel
ls,a
ndJ.
S.D
iana
. 197
.5. Surveyofthefreshwaterfishesandtheuhabitats
in th
e co
asta
l dra
inag
es o
f sou
ther
n C
alifo
mia
. Nah
lral
Hist
ory
Mus
eum
of h
a Ang
eles
C
ount
y.Fi
nal R
epor
t toCalifomiaDepamnentofFishandGame,InlaodFisheries D
ivis
ion.
36
4 pp
. gR
eeve
s, G
. 19
85. C
ompe
titio
n be
twee
n re
dsid
e sh
iner
s an
d st
eelh
ead
trout
juve
nile
s in
the
U
mpq
ua R
iver
. Dis
serta
tion,
Ore
gon
Stat
e U
nive
rsity
, Cor
valis
, Ore
gon
'OFo
ntai
ne, B
. 19
88. A
n as
sess
men
t of
habi
tat
enha
ncem
ent m
easu
res
and
fact
ors
limiti
ng
prod
uctio
n of
ste
elhe
ad tr
out i
n tri
buta
ries t
o th
eUrn
pqua
Riv
er. M
.S. T
hesi
s, O
rego
n St
ate
Uni
vers
ity, C
orva
lis, O
re.
the
pres
ence
or a
bsen
ce o
fexo
tic
fish
spec
ies.
For
the
last
60
year
s, M
alin
e bas
e C
amp
Pend
leto
n ha
sbee
n pu
mpi
ng g
roun
d w
ater
from
the
aqui
ferb
enea
th th
e S
MC
drai
nage
. W
hile
str
eam
con
ditio
ns a
re c
urre
ntly
cap
able
of s
uppo
rtin
g a
stee
lhea
d po
pula
tion,
al
tern
ativ
es to
redu
ce o
r elim
inat
e th
is p
ress
ure
on th
e re
sour
ce c
an o
nly
bene
fit t
he
trou
t. A
dditi
onal
eff
orts
are
nee
ded
to s
eek
an a
ccep
tabl
e an
d ef
fect
ive
met
hod
for
cont
rolli
ng ex
otic
fish
spec
ies o
n th
e dr
aina
ge.
Reg
ardl
ess o
fthe
met
hods
em
ploy
ed,
this
und
erta
king
can
not b
e su
cces
sfU
l in
the
long
-ter
m u
nles
s re
-inf
esta
tion
from
the
sour
ce is
con
trol
led,
ifth
e so
urce
stil
l exi
sts.
Cur
rent
ly, t
he p
opul
atio
ns o
f exo
tic fi
sh
spec
ies w
ithin
the
dra
inag
e ar
e se
lf-s
usta
inin
g an
d an
nual
rep
opul
atio
n of
the
cree
k oc
cur f
rom
adu
lts w
ithin
the
cree
k.
Eve
n th
ough
the
San
Mat
eo d
rain
age
stee
lhea
dira
inbo
w h
out h
ave
extr
emel
y lo
w
popu
latio
nnum
bers
bas
edon
Dep
arhn
ent s
urve
ys, t
heir
cont
inue
dsur
viva
l ine
xtre
mel
y ha
rsh
cond
ition
s mak
es th
eir p
rese
rvat
ion
even
mor
e im
port
ant.
All
juve
nile
coa
stal
ra
inbo
w t
rout
hav
e th
e po
tent
ial
to e
mig
rate
fro
m t
heir
coa
stal
str
eam
and
bec
ome
stee
lhea
d ir
resp
ectiv
e of t
heir
par
enta
ge, a
nd th
eref
ore
are
extr
emel
y im
port
ant t
o th
e pe
rsis
tenc
e of
the
popu
latio
n (B
ehnk
e 19
92).
Thi
s pol
ymor
phic
pop
ulat
ion
stru
ctur
e al
low
s per
sist
ence
in a
n en
viro
nmen
t tha
t is f
requ
ently
sub
optim
al an
d po
pula
tions
of
this
type
may
be
nece
ssar
y fo
r the
long
-ter
m p
ersi
sten
ce o
f the
pop
ulat
ion
(Joh
nson
19
85, T
itus
and
Mos
egaa
rd 1
992,
Nor
thco
te 1
997)
. O
ften
spe
cies
occ
upyi
ng th
e m
argi
ns o
fthe
irra
nge
bene
fit f
rom
apo
lym
o~ph
ic life h
isto
ry w
here
con
ditio
nsm
ay b
e un
stab
le. T
his
life-
hist
ory
plas
ticity
, in
a d
rain
age t
hat e
xper
ienc
es u
nrel
iabl
e st
ream
fl
ow fo
r im
mig
ratin
g ad
ults
and
em
igra
ting
smol
ts, a
nda
cons
tant
exo
tic p
rese
nce,
is
undo
ubte
dly
the
reas
on s
outh
ern
stee
lhea
dhai
nbow
trou
t con
tinue
to o
ccup
y th
e Sa
n M
ateo
Cre
ek d
rain
age.
AC
KN
OW
LED
GM
EN
TS
Dr. J.Nielsenprovidedessentialcommentsonthe g
enet
ic po
rtio
noft
hism
anus
crip
t. I a
m th
ankf
ul to
all t
he re
view
ers t
hat a
ssis
ted
in th
e ed
iting
of t
he te
xt a
nd to
C. M
iller
fo
r pro
vidi
ng a
ssis
tanc
e on
the
figu
res.
LIT
ER
AT
UR
E C
ITE
D
Beh
nke,
R.J
. 19
92. N
ativ
e ho
ut o
f w
este
rn N
orth
Am
eric
a. A
mer
ican
Fis
herie
s So
ciet
y,
Mon
ogra
ph N
o. 6
. 275
pp.
B
ell,
M.C
. 198
6. F
ishe
ries h
andb
ook
of e
ngin
eerin
g req
uire
men
ts an
d bi
olog
ical
crite
ria. F
ish
PassageDevelopmentandEvaluationPmgram,U.S.Army Cor
psof
Eng
inee
rs,N
orth
Paci
fic
Div
isio
n. P
ortla
nd, O
rego
n, 2
90 p
p.
Bov
ee,
K.D
. 19
78. P
roba
bilit
y-of
-use
crit
eria
for
the
fam
ily S
alm
onid
ae. I
nstre
am F
low
In
form
atio
n Pa
per 4
, Uni
ted
Stat
es F
ish
and
Wild
life
Serv
ice,
FW
SIO
BS-
78/0
7. 7
9 pp
. G
reen
woo
d, K
.R.
1988
. A c
once
ptua
l dra
ft: C
me
l R
iver
Wat
ersh
ed M
anag
emen
t Pla
n.
Mon
tere
y Pe
nins
ula
Wat
er D
istri
ct
John
son,
B. 1
985.
Life
his
tory
pat
tern
s ofr
esid
ent a
nd se
a-ru
n m
igra
nt b
row
n tro
ut in
Now
ay.
Tran
sact
ions
of th
e A
mer
ican
Fis
herie
s Soc
iety
. 1 1
4:18
2-19
4.
154
CA
LIF
OR
NIA
FIS
H A
ND
GA
ME
Nie
lsen
, J.L
., C
.A.G
an, a
nd W
.K. T
hom
as.
1994
. Dif
fere
nces
in g
enet
ic d
iver
sity
for
mtD
NA
be
twee
n ha
tche
ryan
dwild
popu
latio
nsof
Onc
orhy
nchw
.Can
adia
nJou
mal
ofFi
sher
iesa
nd
Aqu
atic
Sci
ence
s, 5
1 (S
uppl
1):
290-
297.
N
orth
cote
. T.G
. 19
97. Why s
ea ru
n? A
n ex
plor
atio
n in
to th
e m
igra
tory
lres
iden
cy s
pect
rum
of
coas
tal c
utth
roat
trou
t. Pa
ges
20-2
6 in
: J.
D. H
all,
P.A
. Bis
son,
and
R.E
. Gre
ssw
ell,
edit
ors.
Se
a-ru
n cu
tthro
at tr
out:
biol
ogy,
rnan
agm
emen
t and
futu
re c
onse
rvat
ion.
Ore
gon
Cha
pter
, A
mer
ican
Fis
heri
es, C
owal
lis.
Pag
es 2
0-26
. Rieman,B.E.,D.L.MyersandR.L.
Nie
lsen
. 199
4Use
ofot
olit
hmic
roch
emis
t1yt
odis
crim
inat
e O
ncor
hvnc
hus
nerk
a of
resi
dent
and
ana
drom
ous o
rim
. Can
adia
n Jo
urna
l of F
ishe
ries
and
-
Aqu
atic
Sci
ence
s, 5
1 :68
-77
Stou
der,
D.J
.,P.A
. Bis
son,
and
R.J
.Nai
man
,edi
tors
. 1997.Pacificsalmanandtheirecosystems:
stat
us a
nd f
utur
e op
tions
. Cha
pman
and
Hal
l, N
ew Y
ork.
T
itus
, R
.G.
and
H.
Mos
egaa
rd.
1992
. Flu
ctua
ting
recr
uitm
ent
and
vari
able
lif
e hi
stor
y of
m
igra
tory
bro
wn
trou
t, Sa
lmo
mtt
a L
., in
a s
mal
l, un
stab
le s
trea
m. J
oum
al o
f Fi
sher
ies
Bio
logy
.41:
239-
255.
Rec
eive
d: 1
3 Se
ptem
ber 2
002
Acc
epte
d: 3
Sep
tem
ber
2003