INTRODUCTION MATE0 SAN OF IN TROUT STATUS RAINBOW …...Spawning behavior was described on two...
Transcript of INTRODUCTION MATE0 SAN OF IN TROUT STATUS RAINBOW …...Spawning behavior was described on two...
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