GYNOGENESIS FISH GENETICS PRACTICUM REPORT
TRIPLOIDIZATION AND HYBRIDIZATION
Add
r
e
ss
ed F
or fulfil
W
rong
O
n
e
t
a
sk pr
ac
ti
c
um
Ge
n
e
ti
c
s
C
ompil
ed b
y
:
BRADFOR H
.
DEPARTEMENT OF BIOLOGY
ARIZONA STATE UNIVERSITY
PIG
INTRODUCTION
1
.
1
Bac
kgroun
d Be
hin
d
F
ish is on
e
of th
e
high
e
st sour
ce
s of prot
e
in in th
e
worl
d
,
a
n
d
it
ca
n
be
o
b
t
a
in
ed e
ith
e
r
b
y
ca
t
c
hing it
d
ir
ec
tly from n
a
tur
e
or through
a
qu
ac
ultur
e
.
C
urr
e
ntly
,
th
e de
m
a
n
d
for fish is r
a
pi
d
ly in
c
r
ea
sing
,
b
ut
n
a
tur
a
l fish pro
d
u
c
tion
a
lon
e
is insuffi
c
i
e
nt to m
ee
t this growing
de
m
a
n
d
.
T
h
e
r
e
for
e
,
pr
ec
is
e
m
ea
sur
e
s
a
r
e
n
eeded
,
a
n
d
on
e
of th
e
most r
e
li
ab
l
e
m
e
tho
d
s is through
a
qu
ac
ultur
e
.
H
ow
e
v
e
r
,
a
qu
ac
ultur
e
its
e
lf pr
e
s
e
nts
c
h
a
ll
e
ng
e
s
,
su
c
h
a
s poor pro
d
u
c
tion out
c
om
e
s
.
T
h
e
s
e
poor out
c
om
e
s
ca
n
be a
ttri
b
ut
ed
to v
a
rious f
ac
tors
,
in
c
lu
d
ing
e
nvironm
e
nt
a
l
c
on
d
itions
,
ec
osyst
e
m
ba
l
a
n
ce
,
hum
a
n r
e
sour
ce
s
,
a
n
d
th
e
qu
a
lity of
b
roo
d
sto
c
k
a
n
d
th
e
ir offspring
.
T
o improv
e
th
e
qu
a
lity of
b
roo
d
sto
c
k
a
n
d
th
e
ir offspring
,
g
e
n
e
ti
c e
ngin
ee
ring t
ec
hniqu
e
s
ca
n
be e
mploy
ed
.
Ge
n
e
ti
c
s
,
th
e
stu
d
y of
inh
e
rit
a
n
ce a
n
d d
iv
e
rsity of tr
a
its
,
off
e
rs m
e
tho
d
s su
c
h
a
s gynog
e
n
e
sis
,
triploi
d
iz
a
tion
,
a
n
d
hy
b
ri
d
iz
a
tion to
e
nh
a
n
ce
fish qu
a
lity
.
G
ynog
e
n
e
sis
,
for
e
x
a
mpl
e
,
is
a
pro
ce
ss wh
e
r
e
offspring inh
e
rit only m
a
t
e
rn
a
l
c
h
a
r
ac
t
e
risti
c
s
b
y
de
v
e
loping
a
n
e
gg without sp
e
rm
c
ontri
b
ution
,
r
e
sulting in
homozygous
(
c
lon
ed
)
offspring
.
T
his pro
ce
ss
ca
n o
cc
ur n
a
tur
a
lly or
a
rtifi
c
i
a
lly
,
with
a
rtifi
c
i
a
l gynog
e
n
e
sis involving ultr
a
viol
e
t r
ad
i
a
tion on
sp
e
rm
a
n
d
th
e
rm
a
l sho
c
k to in
d
u
ce de
v
e
lopm
e
nt
.
T
h
e
su
cce
ss of this
t
ec
hniqu
e de
p
e
n
d
s on th
e
timing
,
t
e
mp
e
r
a
tur
e
,
a
n
d d
ur
a
tion of th
e
sho
c
k
.
T
riploi
d
iz
a
tion is
a
t
ec
hniqu
e e
mploy
ed
to inhi
b
it th
e
form
a
tion of
s
e
x
ce
lls in fish
,
a
llowing th
e
m to grow r
a
pi
d
ly
.
T
his
acce
l
e
r
a
t
ed
growth
o
cc
urs
beca
us
e
th
e e
n
e
rgy th
a
t woul
d
typi
ca
lly
be
us
ed
for g
a
m
e
t
e
de
v
e
lopm
e
nt is inst
ead
r
ed
ir
ec
t
ed
to th
e
fish
'
s ov
e
r
a
ll growth
.
O
n th
e
oth
e
r h
a
n
d
,
hy
b
ri
d
iz
a
tion involv
e
s th
e a
rtifi
c
i
a
l
b
r
eed
ing of two
d
iff
e
r
e
nt
typ
e
s of fish with
de
sir
ab
l
e
tr
a
its
.
T
his pro
ce
ss is
c
on
d
u
c
t
ed e
xt
e
rn
a
lly to
e
nh
a
n
ce
th
e
offspring
'
s
c
h
a
r
ac
t
e
risti
c
s
,
r
e
sulting in improv
ed
qu
a
liti
e
s
th
a
t surp
a
ss thos
e
of th
e
p
a
r
e
nt fish
.
2
.
6
Ide
ntifi
ca
tion
P
ro
b
l
e
m
O
v
e
r tim
e
,
ad
v
a
n
ce
m
e
nts in t
ec
hnology h
a
v
e
in
c
r
ea
singly
influ
e
n
ced
th
e
fi
e
l
d
of fish
e
ri
e
s
,
p
a
rti
c
ul
a
rly in
a
qu
ac
ultur
e
.
O
n
e
not
ab
l
e
a
r
ea
is
a
rtifi
c
i
a
l sp
a
wning
,
wh
e
r
e
hy
b
ri
d
iz
a
tion is
c
ommonly
e
mploy
ed d
u
e
to its r
e
l
a
tiv
e
simpli
c
ity
c
omp
a
r
ed
to oth
e
r m
e
tho
d
s
.
I
n this
c
ont
e
xt
,
w
e
will o
b
s
e
rv
e a
n
d a
n
a
lyz
e
thr
ee a
rtifi
c
i
a
l sp
a
wning t
ec
hniqu
e
s
:
hy
b
ri
d
iz
a
tion
,
gynog
e
n
e
sis
,
a
n
d
triploi
d
iz
a
tion
.
1
.
1
.
1
Ob
j
ec
tiv
e P
r
ac
ti
c
um
T
h
e
o
b
j
ec
tiv
e
s of th
e
pr
ac
ti
c
um on
a
rtifi
c
i
a
l gynog
e
n
e
sis
,
triploi
d
iz
a
tion
,
a
n
d
hy
b
ri
d
iz
a
tion
a
r
e
for stu
de
nts to un
de
rst
a
n
d
th
e e
m
b
ryology
involv
ed
in th
e
s
e
pro
ce
ss
e
s
,
i
de
ntify
b
roo
d
sto
c
k th
a
t
a
r
e
r
ead
y to
sp
a
wn
,
a
n
d bec
om
e
f
a
mili
a
r with th
e
t
ec
hniqu
e
s of inj
ec
tion
a
n
d
stripping
.
Add
ition
a
lly
,
stu
de
nts shoul
d
l
ea
rn
a
rtifi
c
i
a
l sp
a
wning
m
e
tho
d
s
,
in
c
lu
d
ing gynog
e
n
e
sis
,
triploi
d
iz
a
tion
,
a
n
d
hy
b
ri
d
iz
a
tion
,
a
s
w
e
ll
a
s
d
iff
e
r
e
nti
a
t
e be
tw
ee
n f
e
rtiliz
ed a
n
d
unf
e
rtiliz
ed e
ggs
.
F
in
a
lly
,
th
e
y shoul
d be ab
l
e
to tr
ac
k th
e de
v
e
lopm
e
nt of
e
ggs from f
e
rtiliz
a
tion
through to h
a
t
c
hing
.
4
REVIEW
BIBLIOGRAPHY
2
.
1
.
F
ish
C
om
e
t
T
h
e
s
e
fish
a
r
e
f
a
vor
ed
for th
e
ir vi
b
r
a
nt
c
olors
,
r
a
nging from whit
e
,
y
e
llow
,
a
n
d
r
ed
to v
a
rious
c
om
b
in
a
tions
,
a
s w
e
ll
a
s th
e
ir uniqu
e
sh
a
p
e
s
a
n
d
gr
ace
ful mov
e
m
e
nts
.
D
u
e
to th
e
ir
ada
pt
ab
ility
,
C
om
e
t fish
ca
n
be ea
sily
k
e
pt in v
a
rious
e
nvironm
e
nts
a
roun
d
th
e
worl
d
,
provi
ded
th
e c
on
d
itions
a
r
e
c
l
ea
n
a
n
d
h
ea
lthy
.
T
his
ada
pt
ab
ility
,
a
long with th
e
ir
ae
sth
e
ti
c a
pp
ea
l
,
h
a
s
l
ed
m
a
ny
e
nthusi
a
sts to
c
omm
e
r
c
i
a
liz
e
th
e
m
,
turning
a
ho
bb
y into
a
profit
ab
l
e
v
e
ntur
e
.
T
h
e c
ultiv
a
tion of th
e
s
e
fish is r
e
l
a
tiv
e
ly simpl
e
,
r
e
quiring
minim
a
l l
a
n
d a
n
d
r
e
sour
ce
s
,
with th
e
prim
a
ry inv
e
stm
e
nt
be
ing in skills
a
n
d
t
ec
hniqu
e
s th
a
t must
be c
ontinuously improv
ed
.
T
h
e C
om
e
t fish
be
longs to
th
e C
yprini
dae
f
a
mily within th
e
g
e
nus
Ca
r
a
ssius
,
a
n
d
its
c
l
a
ssifi
ca
tion
in
c
lu
de
s
P
hylum
C
hor
da
t
a
,
C
l
a
ss
P
is
ce
s
,
S
u
bc
l
a
ss
Te
l
e
osti
a
,
O
r
de
r
O
st
a
riphisysoi
de
i
,
a
n
d S
u
b
or
de
r
C
yprinoi
dea
.
2
.
1
.
1
B
iology
F
ish
C
om
e
t
C
om
e
t fish n
a
tur
a
lly inh
ab
it riv
e
rs
,
l
a
k
e
s
,
pon
d
s
,
a
n
d
oth
e
r
b
o
d
i
e
s of w
a
t
e
r
with slow or st
a
gn
a
nt flows
,
oft
e
n
a
t
de
pths of up to
20
m
e
t
e
rs
.
T
h
e
y
thriv
e
in fr
e
shw
a
t
e
r
e
nvironm
e
nts with
a
p
H
r
a
ng
e
of
6
.
0
to
8
.
0
a
n
d
w
a
t
e
r
h
a
r
d
n
e
ss
be
tw
ee
n
5
.
0
a
n
d
19
.
0
DGH
.
T
h
e
s
e
fish
a
r
e
w
e
ll
-
ada
pt
ed
to living
in
c
lim
a
t
e
s r
a
nging from
0
to
41
°
C a
n
d a
r
e e
uryh
a
lin
e
,
ab
l
e
to tol
e
r
a
t
e
s
a
linity up to
17
ppt
,
though prolong
ed e
xposur
e ab
ov
e
15
ppt is not i
dea
l
.
C
om
e
t fish f
eed
on
a d
i
e
t of
c
rust
acea
ns
,
ins
ec
ts
,
pl
a
nt m
a
t
e
ri
a
l
,
a
n
d
de
tritus
.
T
h
e
y r
e
pro
d
u
ce b
y l
a
ying
e
ggs on su
b
m
e
rg
ed
v
e
g
e
t
a
tion
.
2
.
1
.
2
Re
pro
d
u
c
tion
F
ish
C
om
e
t
S
p
a
wning in gol
d
fish typi
ca
lly o
cc
urs from th
e
mi
dd
l
e
of th
e e
v
e
ning until
th
e e
n
d
of
da
wn
.
P
rior to sp
a
wning
,
th
e
p
a
r
e
nt gol
d
fish
ac
tiv
e
ly s
ee
k out
de
ns
e a
r
ea
s
,
su
c
h
a
s w
a
t
e
r pl
a
nts or gr
a
ss
e
s
c
ov
e
ring th
e
w
a
t
e
r surf
ace
,
whi
c
h s
e
rv
e a
s
a
su
b
str
a
t
e
for th
e e
ggs to
ad
h
e
r
e
to
a
n
d a
lso h
e
lp
5
stimul
a
t
e
th
e
sp
a
wning pro
ce
ss
.
T
h
e e
ggs of
C
om
e
t fish
a
r
e
sti
c
ky
,
roun
d
,
a
n
d c
l
ea
r
,
with
a d
i
a
m
e
t
e
r of
1
.
5
-
1
.
8
mm
a
n
d a
w
e
ight of
0
.
17
-
0
.
20
mg
.
T
h
e
siz
e
of th
e e
ggs v
a
ri
e
s
de
p
e
n
d
ing on th
e a
g
e
,
siz
e
,
or w
e
ight of th
e
p
a
r
e
nt fish
.
A
ft
e
r f
e
rtiliz
a
tion
,
th
e e
m
b
ryo
de
v
e
lops insi
de
th
e e
gg
,
a
n
d
within
2
-
3
da
ys
,
th
e e
ggs h
a
t
c
h into l
a
rv
ae
.
T
h
e
s
e
l
a
rv
ae
poss
e
ss
a
l
a
rg
e
yolk s
ac
,
whi
c
h s
e
rv
e
s
a
s
a
foo
d
r
e
s
e
rv
e
for
2
-
4
da
ys
.
I
niti
a
lly
,
th
e
l
a
rv
ae
a
r
e a
tt
ac
h
ed a
n
d
mov
e
with th
e
yolk s
ac
,
m
ea
suring
ab
out
0
.
5
-
0
.
6
mm in
siz
e a
n
d
w
e
ighing
18
-
20
mg
.
T
h
e
l
a
rv
ae
turn whit
e
within
4
-
5
da
ys
,
a
t
whi
c
h st
a
g
e
th
e
y r
e
quir
e e
xt
e
rn
a
l foo
d
sour
ce
s
,
prim
a
rily zoopl
a
nkton lik
e
moin
a a
n
d da
phni
a
,
to surviv
e
.
T
h
e
l
a
rv
ae
,
known
a
s whit
e
fish
,
c
onsum
e
foo
d e
qu
a
l to
ab
out
60
-
70
%
of th
e
ir
b
o
d
y w
e
ight
da
ily
.
A
ft
e
r
2
-
3
w
ee
ks
,
th
e
whit
e
fish grow into fry
,
m
ea
suring
1
-
3
c
m
a
n
d
w
e
ighing
0
.
1
-
0
.
5
gr
a
ms
.
O
v
e
r th
e
n
e
xt
2
-
3
w
ee
ks
,
th
e
s
e
fry
de
v
e
lop into s
eed
fish
,
r
eac
hing
a
siz
e
of
3
-
5
c
m
a
n
d
w
e
ighing
0
.
5
-
2
.
5
gr
a
ms
.
W
ithin thr
ee
months
,
th
e
y grow
furth
e
r
,
with
eac
h fish w
e
ighing
a
roun
d
100
gr
a
ms
.
2
.
1
.
3
C
y
c
l
e L
if
e F
ish
C
om
e
t
T
h
e
lif
e c
y
c
l
e
of
C
om
e
t fish
be
gins with th
e de
v
e
lopm
e
nt of gon
ad
s
,
wh
e
r
e
f
e
m
a
l
e
s pro
d
u
ce e
ggs in th
e
ir ov
a
ri
e
s
a
n
d
m
a
l
e
s pro
d
u
ce
sp
e
rm in
th
e
ir t
e
st
e
s
.
C
om
e
t fish
ca
n sp
a
wn throughout th
e
y
ea
r
a
n
d a
r
e
not
r
e
stri
c
t
ed b
y s
ea
son
a
l
c
h
a
ng
e
s
.
H
ow
e
v
e
r
,
in th
e
ir n
a
tur
a
l h
ab
it
a
t
,
C
om
e
t
fish oft
e
n sp
a
wn
a
t th
e
st
a
rt of th
e
r
a
iny s
ea
son
,
trigg
e
r
ed b
y th
e
s
ce
nt of
d
ry soil
be
ing inun
da
t
ed
with w
a
t
e
r
.
2
.
2
.
B
iology
G
ol
d
fish
2
.
2
.
1
C
l
a
ssifi
ca
tion
F
ish
S
ir
T
h
e
fish
be
longs to th
e A
nim
a
li
a K
ing
d
om
,
C
hor
da
t
e
s
P
hylum
,
Ac
tinopt
e
rygii
C
l
a
ss
,
C
ypriniform
e
s
O
r
de
r
,
C
yprini
dae Fa
mily
,
C
yprinus
Ge
nus
,
a
n
d
its sp
ec
i
e
s is
C
yprinus
ca
rpio
.
T
his fish h
a
s
a
long
a
n
d
c
ompr
e
ss
ed b
o
d
y
.
I
ts mouth is position
ed a
t th
e
front of th
e
h
ead
,
sp
ec
ifi
ca
lly
a
t th
e
tip of th
e
nos
e
,
with th
e e
soph
a
g
ea
l t
ee
th lo
ca
t
ed a
t th
e
r
ea
r of th
e
mouth
.
T
h
e
fish h
a
s two p
a
irs of
ba
r
be
ls
a
t th
e
front r
e
gion
,
6
a
n
d
its
e
ntir
e b
o
d
y is
c
ov
e
r
ed
in l
a
rg
e
s
ca
l
e
s th
a
t
a
r
e
mor
e
promin
e
nt
c
omp
a
r
ed
to oth
e
r fish
.
I
t h
a
s
a
singl
e
,
c
urv
ed
t
a
il
a
n
d a
long
d
ors
a
l fin
th
a
t is
a
lign
ed
opposit
e
to its p
e
lvi
c
fins
,
whi
c
h
a
r
e
position
ed c
los
e
to th
e
p
ec
tor
a
l fins
.
Add
ition
a
lly
,
it h
a
s
a
n op
e
r
c
ulum
a
n
d a
prop
e
r
c
ulum on th
e
p
ec
tor
a
l fins
.
T
h
e
gol
d
fish us
e
s its f
a
ls
e
stom
ac
h to stor
e
foo
d
,
a
n
d
its
gills
c
onsist of v
a
rious
c
ompon
e
nts su
c
h
a
s gill
a
r
c
h
e
s
,
gill r
a
k
e
rs
,
a
n
d
gill
l
a
m
e
ll
ae
.
2
.
2
.
2
Re
pro
d
u
c
tion
F
ish
S
ir
G
ol
d
fish
a
r
e a
group of t
e
l
e
ost
a
nim
a
ls th
a
t
d
o not h
a
v
e e
xt
e
rn
a
l s
e
x
org
a
ns
.
Fe
m
a
l
e
gol
d
fish
d
o not l
a
y sh
e
ll
ed e
ggs
b
ut r
e
l
ea
s
e
unf
e
rtiliz
ed
ov
a
th
a
t r
e
quir
e
sp
e
rm to
de
v
e
lop
.
T
h
e
ov
a a
r
e e
xp
e
ll
ed
from th
e
ov
a
ry
through th
e
ovi
d
u
c
t
a
n
d
r
e
l
ea
s
ed
vi
a
th
e c
lo
aca
.
W
h
e
n r
ead
y to l
a
y
e
ggs
,
th
e
f
e
m
a
l
e
gol
d
fish s
ee
ks out v
e
g
e
t
a
tion or ro
c
ks in th
e
w
a
t
e
r
a
s
a
suit
ab
l
e
sit
e
.
S
imult
a
n
e
ously
,
th
e
m
a
l
e
gol
d
fish r
e
l
ea
s
e
s sp
e
rm from th
e
t
e
sti
c
l
e
s
,
whi
c
h p
a
ss
e
s through th
e
urog
e
nit
a
l tr
ac
t
a
n
d e
xits through th
e
c
lo
aca
,
l
ead
ing to
e
xt
e
rn
a
l f
e
rtiliz
a
tion in th
e
w
a
t
e
r
.
T
his pro
ce
ss r
e
sults in
hun
d
r
ed
s of f
e
rtiliz
ed e
ggs th
a
t
a
tt
ac
h to
a
qu
a
ti
c
pl
a
nts or
c
r
e
vi
ce
s in
ro
c
ks
.
T
h
e
s
e
f
e
rtiliz
ed e
ggs
a
pp
ea
r
a
s tiny whit
e d
ots
a
n
d
will h
a
t
c
h within
24
to
40
hours
.
T
h
e
n
e
wly h
a
t
c
h
ed
fish f
eed
on th
e
r
e
mn
a
nts of th
e
yolk
s
ac
,
visi
b
l
e a
s
a
lump in th
e
ir still
-
c
l
ea
r stom
ac
hs
.
H
ow
e
v
e
r
,
only
a
f
e
w of
th
e
m
a
ny young fish will surviv
e
.
I
n m
a
l
e
g
e
nit
a
l syst
e
ms
,
th
e
t
e
sti
c
l
e
s
a
r
e a
p
a
ir susp
e
n
ded
from
th
e abd
omin
a
l w
a
ll
b
y
a
m
e
s
e
nt
e
ry
,
h
a
ving
a
n ov
a
l sh
a
p
e
with
a
rough
surf
ace
.
T
h
e
y
a
r
e
typi
ca
lly
e
long
a
t
ed a
n
d
oft
e
n lo
b
ul
a
t
ed
.
I
n
E
l
a
smor
a
n
c
hi
,
th
e
r
e
pro
d
u
c
tiv
e c
h
a
nn
e
l
c
onsists of
a
m
e
son
e
phri
c
tu
b
ul
e
wh
e
r
e
th
e
a
nt
e
rior p
a
rt forms th
e a
ff
e
r
e
nt
d
u
c
t
,
c
onn
ec
ting th
e
t
e
sti
c
l
e
s to th
e
m
e
son
e
phros
a
n
d
known
a
s th
e d
u
c
tus
de
f
e
r
e
ns
.
T
h
e
post
e
rior p
a
rt of
this
d
u
c
t
e
xp
a
n
d
s into s
e
min
a
l v
e
si
c
l
e
s
,
l
ead
ing to th
e
form
a
tion of
a
sp
e
rm s
ac
.
T
h
e d
u
c
tus
de
f
e
r
e
ns ultim
a
t
e
ly
d
r
a
ins into th
e c
lo
aca
.
I
n
Te
l
e
osts
,
th
e e
x
c
r
e
tory
a
n
d
r
e
pro
d
u
c
tiv
e d
u
c
ts
a
r
e d
istin
c
t
a
n
d
l
ead
s
e
p
a
r
a
t
e
ly to th
e c
lo
aca
.
F
or f
e
m
a
l
e
s
,
E
l
a
smor
a
n
c
hi ov
a
ri
e
s
a
r
e de
ns
e b
ut
l
e
ss
c
omp
ac
t
a
n
d
lo
ca
t
ed
in th
e a
nt
e
rior p
a
rt of th
e abd
omin
a
l
ca
vity
.
O
nly th
e
right ov
a
ry
de
v
e
lops in m
a
turity
.
I
n
Te
l
e
osts
,
th
e
ov
a
ri
e
s
a
r
e
c
ir
c
ul
a
r
a
n
d
p
a
ir
ed
.
T
h
e E
l
a
smor
a
n
c
hi r
e
pro
d
u
c
tiv
e
tr
ac
t
c
onsists of
7
p
a
ir
ed
stru
c
tur
e
s
,
with th
e a
nt
e
rior p
a
rt fus
ed a
n
d
f
ea
turing
a
singl
e
ostium surroun
ded b
y fim
b
ri
ae
.
T
h
e
ovi
d
u
c
t is n
a
rrow
a
t
b
oth
e
n
d
s
b
ut
wi
de
ns into th
e
ut
e
rus
,
whi
c
h t
e
rmin
a
t
e
s in th
e c
lo
aca
.
I
n
Te
l
e
osts
,
th
e
r
e
pro
d
u
c
tiv
e
tr
ac
t
d
iff
e
rs in stru
c
tur
e a
n
d de
v
e
lopm
e
nt
.
2
.
3
.
Re
pro
d
u
c
tion
F
ish
Re
pro
d
u
c
tion in fish
,
a
s with oth
e
r org
a
nisms
,
involv
e
s n
a
tur
a
l
pro
ce
ss
e
s
a
im
ed a
t sp
ec
i
e
s
c
ontinu
a
tion
.
I
t
e
n
c
omp
a
ss
e
s th
e b
iologi
ca
l
ac
tiviti
e
s r
e
quir
ed
for sp
ec
i
e
s prop
a
g
a
tion
a
n
d
th
e e
m
e
rg
e
n
ce
of offspring
with sp
ec
ifi
c
tr
a
its
,
whi
c
h r
e
sults from g
e
n
e
ti
c c
h
a
ng
e
s
.
F
ish
e
mploy
v
a
rious r
e
pro
d
u
c
tiv
e
str
a
t
e
gi
e
s to
e
nsur
e
r
e
pro
d
u
c
tiv
e
su
cce
ss
,
with
r
e
pro
d
u
c
tiv
e
org
a
ns pl
a
ying
a c
ru
c
i
a
l rol
e
in this pro
ce
ss
.
T
h
e
e
ff
ec
tiv
e
n
e
ss of r
e
pro
d
u
c
tion is influ
e
n
ced b
y th
e
fish
'
s
e
nvironm
e
nt
a
l
c
on
d
itions
.
C
h
a
ng
e
s in th
e e
nvironm
e
nt
ca
n imp
ac
t
d
iff
e
r
e
nt fish sp
ec
i
e
s
in v
a
rious w
a
ys
,
a
n
d
som
e
fish
e
v
e
n migr
a
t
e
long
d
ist
a
n
ce
s to sp
a
wn
.
S
u
cce
ssful sp
a
wning is
c
los
e
ly link
ed
to th
e
timing
a
n
d
lo
ca
tion of
r
e
pro
d
u
c
tion
,
whi
c
h
a
r
e
influ
e
n
ced b
y
e
n
d
o
c
rin
e
fun
c
tions
.
Ba
s
ed
on typ
e
s r
e
pro
d
u
c
tion
A
n
d
s
e
xu
a
lity
,
fish
ca
n in
d
iff
e
r
e
nti
a
t
e
bec
om
e
3
typ
e
s
,
th
a
t is
:
B
is
e
xu
a
l
B
is
e
xu
a
lity in fish
ca
n
be
un
de
rstoo
d a
s
a
tr
a
it wh
e
r
e a
singl
e
sp
ec
i
e
s
e
xhi
b
its
b
oth m
a
l
e a
n
d
f
e
m
a
l
e c
h
a
r
ac
t
e
risti
c
s
.
T
his
ca
n
be d
istinguish
ed
through prim
a
ry
a
n
d
s
ec
on
da
ry s
e
xu
a
l tr
a
its
.
P
rim
a
ry s
e
xu
a
l tr
a
its
,
visi
b
l
e
only through surgi
ca
l
e
x
a
min
a
tion
,
in
c
lu
de
th
e
r
e
pro
d
u
c
tiv
e
org
a
ns su
c
h
a
s t
e
st
e
s
a
n
d d
u
c
ts in m
a
l
e
s
,
a
n
d
ov
a
ri
e
s
a
n
d d
u
c
ts in f
e
m
a
l
e
s
.
Sec
on
da
ry
s
e
xu
a
l tr
a
its
ca
n
be
i
de
ntifi
ed
through s
e
xu
a
l
d
imorphism
,
whi
c
h involv
e
s
d
iff
e
r
e
n
ce
s in morphology
a
n
d d
i
c
hrom
a
tism
,
or
c
olor v
a
ri
a
tions
be
tw
ee
n
s
e
x
e
s
.
U
nis
e
xu
a
l
U
nis
e
xu
a
l org
a
nisms
a
r
e de
fin
ed a
s thos
e
poss
e
ssing only on
e
s
e
x
.
I
n som
e
fish sp
ec
i
e
s
,
s
e
x
de
t
e
rmin
a
tion is simplifi
ed beca
us
e a
ll
8
in
d
ivi
d
u
a
ls
a
r
e e
ss
e
nti
a
lly f
e
m
a
l
e
.
A
n
e
x
a
mpl
e
of this ph
e
nom
e
non is th
e
molly
-
a
m
a
zon fish
(
P
o
ec
ili
a
11
m
b
ryog
),
whi
c
h w
a
s first
d
is
c
ov
e
r
ed a
s
a
f
e
m
a
l
e
.
T
his fish
e
xhi
b
its unis
e
xu
a
l r
e
pro
d
u
c
tion
b
y using sp
e
rm from
a
m
a
l
e
of th
e
s
a
m
e
g
e
nus to stimul
a
t
e e
gg
de
v
e
lopm
e
nt
,
b
ut sin
ce
m
a
l
e
a
n
d
f
e
m
a
l
e c
hromosom
e
s
d
o not
c
om
b
in
e
,
only f
e
m
a
l
e
s
a
r
e
pro
d
u
ced
.
T
his pro
ce
ss
,
known
a
s
11
m
b
ryog
e
n
e
sis
,
r
e
sults in th
e
form
a
tion of
uniform f
e
m
a
l
e
offspring
.
He
rm
a
phro
d
it
e
A
h
e
rm
a
phro
d
it
e
is
a
n org
a
nism with
a
m
b
iguous g
e
nit
a
li
a
.
T
h
e
r
e
a
r
e
thr
ee
typ
e
s of h
e
rm
a
phro
d
it
e
s
:
syn
c
hronous
,
prot
a
n
d
rous
,
a
n
d
protogynous
.
S
yn
c
hronous h
e
rm
a
phro
d
it
e
s
a
r
e
fish with gon
ad
s
c
ont
a
ining
b
oth m
a
l
e a
n
d
f
e
m
a
l
e
s
e
x
ce
lls th
a
t
ca
n fun
c
tion
simult
a
n
e
ously
.
P
rot
a
n
d
rous h
e
rm
a
phro
d
it
e
s
a
r
e
fish th
a
t st
a
rt
a
s m
a
l
e
s
a
n
d
l
a
t
e
r
c
h
a
ng
e
to f
e
m
a
l
e
s
d
uring th
e
ir lif
e
tim
e
,
su
c
h
a
s th
e b
l
ac
k porgy
,
whi
c
h tr
a
nsitions from m
a
l
e
to f
e
m
a
l
e b
y
a
g
e
thr
ee
.
P
rotogynous
h
e
rm
a
phro
d
it
e
s
a
r
e
fish th
a
t st
a
rt
a
s f
e
m
a
l
e
s
a
n
d
l
a
t
e
r
bec
om
e
m
a
l
e
s
,
su
c
h
a
s
Lab
roi
de
s
d
imi
d
i
a
tus
.
T
h
e
r
e
pro
d
u
c
tiv
e
org
a
ns of fish
,
known
a
s gon
ad
s
,
d
iff
e
r
be
tw
ee
n
m
a
l
e
s
a
n
d
f
e
m
a
l
e
s
.
I
n m
a
l
e
fish
,
th
e
gon
ad
s
a
r
e
r
e
f
e
rr
ed
to
a
s t
e
sti
c
l
e
s
,
whi
c
h
a
r
e
int
e
rn
a
l
,
e
long
a
t
ed
,
a
n
d
typi
ca
lly
c
om
e
in p
a
irs
.
T
h
e
y
ca
n
c
onstitut
e
up to
12
%
or mor
e
of th
e
fish
'
s
b
o
d
y w
e
ight
a
n
d a
r
e
usu
a
lly
whit
e
or y
e
llowish in
c
olor
.
Fe
m
a
l
e
fish poss
e
ss ov
a
ri
e
s
,
whi
c
h
a
r
e a
lso
int
e
rn
a
l
a
n
d
usu
a
lly p
a
ir
ed
.
Ma
tur
e
ov
a
ri
e
s
ca
n
acc
ount for
30
-
70
%
of th
e
fish
'
s
b
o
d
y w
e
ight
a
n
d ca
n v
a
ry in
c
olor
,
a
pp
ea
ring whitish initi
a
lly
a
n
d
turning y
e
llowish
a
s th
e
y m
a
tur
e
.
T
h
e de
v
e
lopm
e
nt of
b
oth t
e
sti
c
l
e
s
a
n
d
ov
a
ri
e
s is influ
e
n
ced b
y f
ac
tors su
c
h
a
s
a
g
e
,
sp
ec
i
e
s
,
a
n
d
siz
e
.
F
ish
e
xhi
b
it v
a
rying r
e
pro
d
u
c
tiv
e c
y
c
l
e
s
.
F
or inst
a
n
ce
,
s
a
lmon
,
s
ea
l
a
mpr
e
ys
,
a
n
d ee
ls r
e
pro
d
u
ce
only on
ce
in th
e
ir lif
e
tim
e
,
whil
e
guppi
e
s
r
e
pro
d
u
ce a
pproxim
a
t
e
ly
e
v
e
ry four w
ee
ks
.
Add
ition
a
lly
,
som
e
fish sp
a
wn
two to thr
ee
tim
e
s
a
y
ea
r
,
su
c
h
a
s th
e M
oz
a
m
b
iqu
e
til
a
pi
a
.
F
ish
a
lso s
e
l
ec
t
d
iff
e
r
e
nt typ
e
s of sp
a
wning h
ab
it
a
ts
:
thos
e
th
a
t sp
a
wn on ro
c
ky
ba
s
e
s
a
r
e
known
a
s lithophilous fish
,
thos
e
on s
a
n
d a
r
e
t
e
rm
ed
ps
a
mophilous
,
thos
e
in op
e
n w
a
t
e
r
a
r
e ca
ll
ed
p
e
l
a
gophilous
,
a
n
d
thos
e
on
dead
sh
e
lls
a
r
e
r
e
f
e
rr
ed
to
a
s ostr
ac
ophilous
.
9
F
ish
ca
n
be c
l
a
ssifi
ed
into thr
ee
typ
e
s
ba
s
ed
on wh
e
r
e e
m
b
ryo
de
v
e
lopm
e
nt
a
n
d
f
e
rtiliz
a
tion o
cc
ur
.
T
h
e
first typ
e
is ovip
a
rous
,
wh
e
r
e
fish
l
a
y
e
ggs
d
uring sp
a
wning
;
most fish f
a
ll into this
ca
t
e
gory
.
T
h
e
s
ec
on
d
typ
e
is vivip
a
rous
,
wh
e
r
e e
m
b
ryo
de
v
e
lopm
e
nt t
a
k
e
s pl
ace
within th
e
p
a
r
e
nt
’
s
b
o
d
y
a
n
d
is influ
e
n
ced b
y
a
pl
ace
nt
a
,
a
s s
ee
n in som
e
e
l
a
smo
b
r
a
n
c
h fish
.
T
h
e
thir
d
typ
e
is ovovivip
a
rous
,
wh
e
r
e e
m
b
ryos
a
lso
de
v
e
lop within th
e b
o
d
y
,
b
ut without th
e
support of
a
pl
ace
nt
a
;
inst
ead
,
th
e
y r
e
ly on th
e
yolk of th
e e
gg
,
a
s o
b
s
e
rv
ed
in ro
c
kfish
(
Sc
orp
ae
ni
dae
).
E
m
b
ryo
de
v
e
lopm
e
nt
be
gins wh
e
n m
a
l
e
sp
e
rm f
e
rtiliz
e
s th
e e
gg
ce
ll
.
Fe
rtiliz
a
tion is
c
ompl
e
t
e
on
ce
th
e e
gg
ce
ll nu
c
l
e
us
a
n
d
sp
e
rm
a
tozoon
m
e
rg
e
,
forming
a
zygot
e
.
T
h
e
st
a
g
e
s of fish
e
m
b
ryo
de
v
e
lopm
e
nt in
c
lu
de
morul
a
,
b
l
a
stul
a
,
g
a
strul
a
,
a
n
d
org
a
nog
e
n
e
sis
.
2
.
4
.
S
p
e
rm
a
tozo
a
S
p
e
rm
a
tozo
a a
r
e
m
a
l
e
g
a
m
e
t
e
s th
a
t f
e
rtiliz
e
f
e
m
a
l
e e
gg
ce
lls in
s
e
xu
a
lly r
e
pro
d
u
c
ing org
a
nisms
,
in
c
lu
d
ing
a
nim
a
ls
a
n
d
som
e
pl
a
nts
.
U
nlik
e
most multi
ce
llul
a
r
ce
lls
,
sp
e
rm
a
tozo
a
h
a
v
e a
stru
c
tur
e c
onsisting of
a
h
ead a
n
d a
t
a
il
,
a
llowing th
e
m to mov
e
in
de
p
e
n
de
ntly
.
T
h
e
h
ead
c
ont
a
ins minim
a
l
c
ytopl
a
sm
c
omp
a
r
ed
to oth
e
r
ce
lls
a
n
d
is
de
ns
e
ly
p
ac
k
ed
with
c
hromosom
e
s in th
e
nu
c
l
e
us
.
S
p
e
rm
ce
lls
a
r
e
h
a
ploi
d
,
m
ea
ning th
e
y
ca
rry h
a
lf th
e
usu
a
l num
be
r of
c
hromosom
e
s for th
e
ir
sp
ec
i
e
s
.
I
n m
a
mm
a
ls
,
sp
e
rm
a
tog
e
n
e
sis st
a
rts in th
e
t
e
sti
c
l
e
s
d
uring
e
m
b
ryoni
c de
v
e
lopm
e
nt
.
A
roun
d
pu
be
rty
,
prim
a
ry sp
e
rm
a
to
c
yt
e
s m
a
tur
e
a
n
d d
ivi
de
to form s
ec
on
da
ry sp
e
rm
a
to
c
yt
e
s
.
T
h
e
s
e ce
lls th
e
n split into
two sp
e
rm
a
ti
d
s
,
whi
c
h
e
v
e
ntu
a
lly m
a
tur
e
into sp
e
rm
a
tozo
a
.
10
F
lui
d
in th
e e
m
b
ryog
e
ni
c ce
m
e
nt provi
de
s
a
w
a
rm
,
moist
e
nvironm
e
nt
e
ss
e
nti
a
l for sp
e
rm surviv
a
l
a
n
d a
llows for th
e
ir mov
e
m
e
nt
.
T
his flui
d a
lso prot
ec
ts th
e
sp
e
rm
a
n
d
r
e
gul
a
t
e
s th
e
ir motility
.
T
h
e e
n
e
rgy
r
e
quir
ed
for th
e
sp
e
rm
’
s whip
-
lik
e
or fl
a
g
e
ll
a
r mov
e
m
e
nt
c
om
e
s from
mito
c
hon
d
ri
a
lo
ca
t
ed a
roun
d
th
e
t
a
il
.
F
or f
e
rtiliz
a
tion to o
cc
ur
,
sp
e
rm
must
be
tr
a
nsf
e
rr
ed
from th
e
m
a
l
e
to th
e
f
e
m
a
l
e
through th
e
v
a
gin
a
or
c
lo
aca
,
wh
e
r
e
gly
c
oprot
e
ins on th
e
sp
e
rm
’
s surf
ace
prot
ec
t th
e
m from th
e
f
e
m
a
l
e
’
s immun
e
syst
e
m
.
A
s sp
e
rm tr
a
v
e
l through th
e
f
e
m
a
l
e
r
e
pro
d
u
c
tiv
e
tr
ac
t
,
on
e
must p
e
n
e
tr
a
t
e
th
e
out
e
r lining of th
e
ovum
.
S
p
ec
i
e
s
-
sp
ec
ifi
c
r
ece
ptors on th
e e
gg
’
s surf
ace e
nsur
e
th
a
t only sp
e
rm
from th
e
s
a
m
e
sp
ec
i
e
s
ca
n f
e
rtiliz
e
th
e e
gg
.
T
h
e ac
rosom
e
,
a
l
a
y
e
r th
a
t
wr
a
ps
a
roun
d
th
e
sp
e
rm
’
s h
ead
,
pl
a
ys
a c
ru
c
i
a
l rol
e
in f
e
rtiliz
a
tion
b
y
protru
d
ing
a
n
d
w
ea
k
e
ning th
e e
gg
’
s out
e
r l
a
y
e
r
.
W
h
e
n this
ac
rosom
e
r
eac
tion o
cc
urs
,
th
e
sp
e
rm
’
s h
ead
fus
e
s with th
e e
gg
'
s m
e
m
b
r
a
n
e a
n
d
r
e
l
ea
s
e
s its
c
ont
e
nts
,
l
ead
ing to th
e
m
e
rging of th
e
sp
e
rm
a
n
d e
gg nu
c
l
e
i
a
n
d
th
e
form
a
tion of
a
zygot
e
,
whi
c
h
de
v
e
lops into
a
n
e
w org
a
nism of th
e
s
a
m
e
sp
ec
i
e
s
.
2
.
5
.
S
p
a
wning
A
rtifi
c
i
a
l
2
.
5
.
1
G
ynog
e
n
e
sis
F
ish
b
r
eed
ing is
a c
ru
c
i
a
l
a
sp
ec
t of fish
c
ultiv
a
tion
.
F
or sust
a
in
ab
l
e
pro
d
u
c
tion
,
th
e
f
a
rm
ed
fish must not only grow
b
ut
a
lso r
e
pro
d
u
ce
e
ff
ec
tiv
e
ly
.
C
ultiv
a
tors
e
mploy v
a
rious t
ec
hniqu
e
s to
ac
hi
e
v
e
this
,
in
c
lu
d
ing hy
b
ri
d
iz
a
tion
,
s
e
x r
e
v
e
rs
a
l
,
polyploi
d
iz
a
tion
,
a
n
d
s
e
l
ec
tiv
e
b
r
eed
ing
.
P
olyploi
d
iz
a
tion involv
e
s m
a
nipul
a
ting
c
hromosom
e
s to
e
nh
a
n
ce
fish qu
a
lity
,
r
e
sulting in s
eed
s with improv
ed
growth r
a
t
e
s
,
e
nvironm
e
nt
a
l tol
e
r
a
n
ce
,
d
is
ea
s
e
r
e
sist
a
n
ce
,
a
n
d
high
e
r m
ea
t yi
e
l
d
.
C
hromosom
e
m
a
nipul
a
tion
ca
n o
cc
ur
d
uring th
e ce
ll
d
ivision
c
y
c
l
e
,
oft
e
n
through th
e add
ition or su
b
tr
ac
tion of h
a
ploi
d
or
d
iploi
d ce
lls
.
I
n fish
a
n
d
oth
e
r
a
nim
a
ls
,
e
xt
e
rn
a
l f
e
rtiliz
a
tion
a
llows for m
a
nipul
a
tion of g
a
m
e
t
e
s or
th
e
f
e
rtiliz
ed e
gg
a
t
d
iff
e
r
e
nt st
a
g
e
s of zygot
e
form
a
tion
.
O
n
e
sp
ec
ifi
c
11
m
e
tho
d
of
c
hromosom
e
m
a
nipul
a
tion is gynog
e
n
e
sis
.
G
ynog
e
n
e
sis is
a
r
e
pro
d
u
c
tiv
e
pro
ce
ss wh
e
r
e a
zygot
e
is form
ed
from f
e
m
a
l
e
g
a
m
e
t
e
s
a
lon
e
,
without
a
ny g
e
n
e
ti
c
input from m
a
l
e
g
a
m
e
t
e
s
.
I
n this pro
ce
ss
,
m
a
l
e
g
a
m
e
t
e
s only s
e
rv
e
to stimul
a
t
e
th
e de
v
e
lopm
e
nt of
th
e e
gg
,
without
c
ontri
b
uting
a
ny g
e
n
e
ti
c
m
a
t
e
ri
a
l
.
G
ynog
e
n
e
sis
ca
n
o
cc
ur
b
oth n
a
tur
a
lly
a
n
d a
rtifi
c
i
a
lly
.
I
t involv
e
s th
e c
r
ea
tion of
a d
iploi
d
zygot
e
without th
e
involv
e
m
e
nt of m
a
l
e
g
a
m
e
t
e
s
,
m
ea
ning m
a
l
e
g
a
m
e
t
e
s
only h
a
v
e a
physi
ca
l rol
e
in th
e
pro
ce
ss
,
whil
e
th
e de
v
e
lopm
e
nt follows
a
p
a
th of p
a
rth
e
nog
e
n
e
ti
c de
v
e
lopm
e
nt from th
e
f
e
m
a
l
e e
gg
.
T
o
ac
hi
e
v
e
this
,
sp
e
rm is oft
e
n irr
ad
i
a
t
ed
to
da
m
a
g
e
its
c
hromosom
e
s
,
pr
e
v
e
nting it
from
c
ontri
b
uting g
e
n
e
ti
ca
lly
a
t
c
on
ce
ption
.
Na
tur
a
lly o
cc
urring
gynog
e
n
e
sis is r
a
r
e beca
us
e
sp
e
rm r
a
r
e
ly
e
nt
e
rs
a
n in
ac
tiv
e e
gg
.
H
ow
e
v
e
r
,
in sp
ec
i
e
s su
c
h
a
s th
e ca
rp
(
Ca
r
a
ssius
a
ur
a
tus gi
be
lio
)
a
n
d
som
e
P
o
ec
ili
dae
in
Me
xi
c
o
,
gynog
e
n
e
sis
ca
n o
cc
ur mor
e
fr
e
qu
e
ntly
.
I
n
a
rtifi
c
i
a
l
gynog
e
n
e
sis
,
sp
e
rm is tr
ea
t
ed
with g
a
mm
a
r
a
ys
,
X
-
r
a
ys
,
or ultr
a
viol
e
t
r
ad
i
a
tion to in
ac
tiv
a
t
e
th
e
g
e
n
e
ti
c
m
a
t
e
ri
a
l
,
a
llowing th
e e
gg to
de
v
e
lop
into
a
zygot
e
without g
e
n
e
ti
c c
ontri
b
ution from th
e
m
a
l
e
.
T
r
ea
tm
e
nt
G
ynog
e
n
e
sis
2
.
Rad
i
a
tion sp
e
rm with r
a
y ultr
a
viol
e
t
Be
for
e
sp
e
rm is
c
om
b
in
ed
with
a
n
e
gg
ce
ll in
a
rtifi
c
i
a
l sp
a
wning
,
th
e
sp
e
rm is tr
ea
t
ed
with
UV
r
ad
i
a
tion
.
T
his pro
ce
ss is int
e
n
ded
to
da
m
a
g
e
th
e
sp
e
rm
'
s g
e
n
e
ti
c
m
a
t
e
ri
a
l
.
T
h
e c
h
e
mi
ca
l
c
omposition of th
e
sp
e
rm
'
s pl
a
sm
a c
or
e
,
or nu
c
l
e
opl
a
sm
,
in
c
lu
de
s
DNA
,
prot
a
min
e
,
a
n
d
non
-
ba
si
c
prot
e
ins
,
whil
e
th
e
s
e
min
a
l pl
a
sm
a c
ont
a
ins prot
e
ins
,
pot
a
ssium
,
so
d
ium
,
m
a
gn
e
sium
,
phosph
a
t
e
,
a
n
d c
hlori
de
.
T
h
e
t
a
il of th
e
sp
e
rm is
c
ompos
ed
of prot
e
ins
,
l
ec
ithin
,
a
n
d c
hol
e
st
e
rol
.
U
ltr
a
viol
e
t light with
w
a
v
e
l
e
ngths
be
low
300
nm is strongly
ab
sor
bed b
y
ce
rt
a
in
b
iologi
ca
l
m
a
t
e
ri
a
ls
,
p
a
rti
c
ul
a
rly nu
c
l
e
i
c ac
i
d
s
,
prot
e
ins
,
a
n
d c
o
e
nzym
e
s
,
a
lthough it
d
o
e
s not ioniz
e a
toms or mol
ec
ul
e
s
a
n
d
h
a
s limit
ed
p
e
n
e
tr
a
tion
ab
ility
.
De
spit
e
its limit
ed
p
e
n
e
tr
a
tion
,
only
a
sm
a
ll fr
ac
tion of th
e UV
light
ca
n
p
e
n
e
tr
a
t
e b
iologi
ca
l m
a
t
e
ri
a
ls
,
y
e
t it still h
a
s
a
high
ab
sorption
e
ffi
c
i
e
n
c
y
.
UV
light with w
a
v
e
l
e
ngths up to
260
nm
ca
n
da
m
a
g
e
pyrimi
d
in
e ba
s
e
s
,
whi
c
h
a
r
e
p
a
rt of th
e
sp
e
rm
'
s g
e
n
e
ti
c
m
a
t
e
ri
a
l
.
A
lthough
UV
irr
ad
i
a
tion
ca
n
a
ff
ec
t th
e
s
e
g
e
n
e
ti
c c
ompon
e
nts
,
it
d
o
e
s not imp
a
ir th
e
sp
e
rm
'
s
12
motility or its
ab
ility to f
e
rtiliz
e a
n
e
gg
,
a
llowing for su
cce
ssful f
e
rtiliz
a
tion
a
n
d e
m
b
ryo
de
v
e
lopm
e
nt
.
2
.
T
r
ea
tm
e
nt sho
c
k t
e
mp
e
r
a
tur
e
A
ft
e
r th
e
sp
e
rm h
a
s un
de
rgon
e
r
ad
i
a
tion tr
ea
tm
e
nt
,
it is
c
om
b
in
ed
with
e
gg
ce
lls
a
n
d
r
e
l
ea
s
ed
into th
e
w
a
t
e
r for f
e
rtiliz
a
tion
.
F
ollowing
f
e
rtiliz
a
tion
,
th
e e
m
b
ryo is su
b
j
ec
t
ed
to
a
n
e
nvironm
e
nt
a
l sho
c
k
,
whi
c
h
ca
n
be e
ith
e
r
a
t
e
mp
e
r
a
tur
e
sho
c
k or hy
d
rost
a
ti
c
pr
e
ssur
e
.
H
y
d
rost
a
ti
c
pr
e
ssur
e
r
e
quir
e
s
c
ompl
e
x
a
n
d c
ostly
e
quipm
e
nt
,
m
a
king it
c
h
a
ll
e
nging to
a
pply to
a
l
a
rg
e
num
be
r of
e
ggs
,
though it
e
ff
ec
tiv
e
ly
ac
hi
e
v
e
s z
e
ro
p
e
r
ce
nt h
e
t
e
rozygosity l
e
v
e
ls
.
Te
mp
e
r
a
tur
e
sho
c
k is mor
e
pr
ac
ti
ca
l
a
n
d
ca
n
be a
ppli
ed
to l
a
rg
e
qu
a
ntiti
e
s
.
T
his sho
c
k is int
e
n
ded
to pr
e
v
e
nt pol
a
r
b
o
d
y
II
from forming
d
uring th
e
s
ec
on
d
m
e
ioti
c d
ivision or to stop
ce
ll
d
ivision
a
ft
e
r
c
hromosom
e d
upli
ca
tion
d
uring th
e
first mitoti
c d
ivision
,
e
nsuring th
a
t th
e c
hromosom
e
num
be
r in th
e e
gg is
d
ou
b
l
ed a
t th
e
be
ginning of zygot
e de
v
e
lopm
e
nt
.
Te
mp
e
r
a
tur
e
sho
c
ks in
c
lu
de b
oth h
ea
t
a
n
d c
ol
d
sho
c
ks
,
with h
ea
t sho
c
k
a
ppli
ed
for
a
short
e
r
d
ur
a
tion
c
omp
a
r
ed
to
c
ol
d
sho
c
k
.
D
uring oog
e
n
e
sis
,
th
e e
gg
ce
ll is initi
a
lly in
a
4
N
st
a
t
e
,
b
ut
a
ft
e
r m
e
iosis
I ce
ll
d
ivision
,
it m
a
tur
e
s to
a
2
N
st
a
t
e a
s th
e
pol
a
r
b
o
d
y
I
is
e
j
ec
t
ed
.
I
n m
e
iosis
,
th
e c
hromosom
e
s
e
t is r
ed
u
ced
to h
a
lf its origin
a
l siz
e
,
in
c
ontr
a
st to mitoti
c ce
ll
d
ivision
,
whi
c
h involv
e
s
ce
ll multipli
ca
tion
a
n
d
d
ou
b
ling
.
G
ynog
e
n
e
sis
ca
n
be e
mploy
ed a
s
a
t
ec
hniqu
e
for purifying fish
b
y
r
e
pl
ac
ing
c
ons
a
nguinity in
b
r
eed
ing pr
ac
ti
ce
s
.
A
rtifi
c
i
a
l gynog
e
n
e
sis
a
llows for th
e c
r
ea
tion of pur
e
lin
e
fish with homozygosity
,
pro
d
u
c
ing
r
e
sults
e
quiv
a
l
e
nt to thos
e
o
b
t
a
in
ed
from s
e
v
e
n to
e
ight g
e
n
e
r
a
tions of
in
b
r
eed
ing in just on
e
g
e
n
e
r
a
tion
.
S
imil
a
rly
,
th
e
homozygosity
ac
hi
e
v
ed
in
on
e
g
e
n
e
r
a
tion of gynog
e
n
e
sis is
c
omp
a
r
ab
l
e
to th
e
homozygosity foun
d
in thr
ee
g
e
n
e
r
a
tions of
c
ons
a
nguin
e
ous
b
r
eed
ing
.
T
h
e
su
cce
ss of this
m
e
tho
d
is influ
e
n
ced b
y f
ac
tors su
c
h
a
s th
e a
g
e
of th
e
zygot
e
,
th
e
d
ur
a
tion of h
ea
t sho
c
k
,
a
n
d
th
e
sp
ec
ifi
c
t
e
mp
e
r
a
tur
e
us
ed
.
T
h
e e
x
ac
t
d
ur
a
tion
a
n
d
t
e
mp
e
r
a
tur
e
for th
e
s
e
tr
ea
tm
e
nts must
be
t
a
ilor
ed
to
eac
h
fish sp
ec
i
e
s
.
G
ynog
e
n
e
sis
ca
n
be e
mploy
ed a
s
a
t
ec
hniqu
e
for purifying fish
a
n
d
r
e
pl
ac
ing
c
ons
a
nguinity in
b
r
eed
ing pr
ac
ti
ce
s
.
Acc
or
d
ing to
R
oh
ad
i
,
D
.
S
.
13
(
1996
),
a
rtifi
c
i
a
l gynog
e
n
e
sis
ca
n
c
r
ea
t
e
pur
e
lin
e
fish with homozygosity
.
T
his m
e
tho
d ac
hi
e
v
e
s th
e
s
a
m
e
l
e
v
e
l of homozygosity in on
e
g
e
n
e
r
a
tion
a
s s
e
v
e
n to
e
ight g
e
n
e
r
a
tions of in
b
r
eed
ing
,
whil
e ac
hi
e
ving th
e
s
a
m
e
l
e
v
e
l of homozygosity in thr
ee
g
e
n
e
r
a
tions of
c
ons
a
nguinity
.
T
h
e
su
cce
ss
of this m
e
tho
d de
p
e
n
d
s on f
ac
tors su
c
h
a
s th
e a
g
e
of th
e
zygot
e
,
th
e
d
ur
a
tion of sho
c
k tr
ea
tm
e
nt
,
a
n
d
th
e
t
e
mp
e
r
a
tur
e
us
ed
.
T
h
e
pr
ec
is
e
timing
a
n
d
t
e
mp
e
r
a
tur
e
for th
e
s
e
tr
ea
tm
e
nts
a
r
e
sp
ec
ifi
c
to
eac
h fish
sp
ec
i
e
s
.
2
.
5
.
2
H
y
b
ri
d
iz
a
tion
H
y
b
ri
d
iz
a
tion involv
e
s
c
rossing
d
iff
e
r
e
nt sp
ec
i
e
s or v
a
ri
e
ti
e
s
,
su
c
h
a
s fish
,
shrimp
,
sh
e
llfish
,
or s
ea
gr
a
ss
e
s
,
to
c
r
ea
t
e
in
d
ivi
d
u
a
ls with
pot
e
nti
a
lly sup
e
rior tr
a
its
.
T
his pro
ce
ss som
e
tim
e
s r
e
sults in st
e
ril
e
hy
b
ri
d
s
,
whi
c
h
ca
n l
ead
to th
e de
v
e
lopm
e
nt of n
e
w str
a
ins
.
S
u
cce
ssful
hy
b
ri
d
iz
a
tion is f
ac
ilit
a
t
ed
wh
e
n
a
rtifi
c
i
a
l r
e
pro
d
u
c
tion t
ec
hniqu
e
s
,
lik
e
e
gg
a
n
d
sp
e
rm stripping
,
a
r
e
us
ed
,
a
s s
ee
n with gol
d
fish
a
n
d
til
a
pi
a
.
Acc
or
d
ing to g
e
n
e
ti
c
r
e
s
ea
r
c
h
,
hy
b
ri
d
iz
a
tion is
ca
t
e
goriz
ed
into two typ
e
s
:
int
e
rsp
ec
ifi
c
,
whi
c
h o
cc
urs
be
tw
ee
n
d
iff
e
r
e
nt sp
ec
i
e
s
,
a
n
d
intr
a
sp
ec
ifi
c
,
whi
c
h o
cc
urs within th
e
s
a
m
e
sp
ec
i
e
s
.
T
h
e
prim
a
ry
d
istinguishing f
ac
tors
in int
e
rv
a
ri
e
ty hy
b
ri
d
iz
a
tion
a
r
e d
iff
e
r
e
n
ce
s in
c
olor
,
form
,
siz
e
,
a
n
d
oth
e
r
b
iologi
ca
l
c
h
a
r
ac
t
e
risti
c
s of th
e
org
a
nisms involv
ed
.
H
y
b
ri
d
iz
a
tion in fish
b
r
eed
ing is
a
w
e
ll
-
e
st
ab
lish
ed
pr
ac
ti
ce
us
ed
to
e
nh
a
n
ce ce
rt
a
in
c
h
a
r
ac
t
e
risti
c
s of fish offspring
.
T
his pro
ce
ss
ca
n involv
e
c
ross
b
r
eed
ing
be
tw
ee
n
d
iff
e
r
e
nt str
a
ins within
a
sp
ec
i
e
s
,
d
iff
e
r
e
nt sp
ec
i
e
s
within
a
g
e
nus
,
or
e
v
e
n
ac
ross g
e
n
e
r
a
or f
a
mili
e
s
.
T
h
e
go
a
l of
hy
b
ri
d
iz
a
tion is to pro
d
u
ce
offspring with sup
e
rior tr
a
its
,
su
c
h
a
s improv
ed
growth r
a
t
e
s
,
be
tt
e
r gon
ada
l m
a
turity
,
in
c
r
ea
s
ed d
is
ea
s
e
r
e
sist
a
n
ce
,
gr
ea
t
e
r
ada
pt
ab
ility to
ad
v
e
rs
e e
nvironm
e
nts
,
a
n
d
mor
e e
ffi
c
i
e
nt foo
d
utiliz
a
tion
.
F
or
e
x
a
mpl
e
,
using th
e
sp
e
rm of th
e c
ommon
ca
rp
(
C
yprinus
ca
rpio
)
for
b
r
eed
ing with
c
om
e
t gol
d
fish
(
Ca
r
a
ssius
a
ur
a
tus
)
a
ims to
c
om
b
in
e
th
e
f
a
st growth r
a
t
e
of
ca
rp with th
e c
los
e
g
e
n
e
ti
c
r
e
l
a
tionship
be
tw
ee
n th
e
two sp
ec
i
e
s
,
ultim
a
t
e
ly pro
d
u
c
ing hy
b
ri
d c
om
e
t gol
d
fish with
e
nh
a
n
ced
g
e
n
e
ti
c
qu
a
liti
e
s
.
2
.
5
.
3
T
riploi
d
iz
a
tion
14
T
riploi
d
iz
a
tion is
a
pro
ce
ss th
a
t r
e
sults in in
d
ivi
d
u
a
ls h
a
ving mor
e
th
a
n two s
e
ts of
c
hromosom
e
s
a
n
d
is us
ed
to
e
nh
a
n
ce
fish growth
.
T
his
t
ec
hniqu
e
involv
e
s
e
ith
e
r physi
ca
l or
c
h
e
mi
ca
l tr
ea
tm
e
nts
.
A
mong th
e
s
e
m
e
tho
d
s
,
t
e
mp
e
r
a
tur
e
sho
c
k is p
a
rti
c
ul
a
rly
ad
v
a
nt
a
g
e
ous
d
u
e
to its
e
ff
ec
tiv
e
n
e
ss
c
omp
a
r
ed
to oth
e
r tr
ea
tm
e
nts
.
T
his sho
c
k involv
e
s
e
xposing
e
m
b
ryos to high
e
r th
a
n norm
a
l t
e
mp
e
r
a
tur
e
s for
a
short
e
r
d
ur
a
tion th
a
n
c
ol
d
sho
c
ks
.
T
h
e
pr
ac
ti
ca
l
a
ppli
ca
tion of h
ea
t sho
c
k for in
d
u
c
ing
polyploi
d
y is most
e
ff
ec
tiv
e
wh
e
n
a
ppli
ed
imm
ed
i
a
t
e
ly
a
ft
e
r f
e
rtiliz
a
tion
for triploi
d
y or shortly
a
ft
e
r th
e
first
d
ivision for t
e
tr
a
ploi
d
y
,
using
a
l
e
th
a
l
t
e
mp
e
r
a
tur
e
.
Ke
y f
ac
tors in h
ea
t sho
c
k tr
ea
tm
e
nt in
c
lu
de
th
e a
g
e
of th
e
zygot
e
,
th
e
timing of th
e
sho
c
k
,
th
e
t
e
mp
e
r
a
tur
e
us
ed
,
a
n
d
th
e d
ur
a
tion of
th
e
tr
ea
tm
e
nt
.
T
h
e
s
e
l
ec
tion of zygot
e a
g
e
,
timing of impl
e
m
e
nt
a
tion
,
t
e
mp
e
r
a
tur
e
,
a
n
d
sho
c
k
d
ur
a
tion must
be
sp
ec
ifi
ca
lly t
a
ilor
ed
for
eac
h sp
e
rm in
a
p
e
tri
d
ish
.
T
h
e
prin
c
ipl
e be
hin
d a
pplying
t
e
mp
e
r
a
tur
e
sho
c
k to f
e
rtiliz
ed e
ggs is to pr
e
v
e
nt th
e e
xpulsion of
th
e
s
ec
on
d
pol
a
r
b
o
d
y
d
uring th
e
m
e
iosis
II d
ivision
.
T
riploi
d
fish
,
whi
c
h poss
e
ss
a
n
add
ition
a
l s
e
t of
c
hromosom
e
s
,
h
a
v
e
thr
ee
s
e
ts
in
eac
h
ce
ll
—
two from th
e e
gg
a
n
d
on
e
from th
e
sp
e
rm
.
Te
tr
a
ploi
d
in
d
ivi
d
u
a
ls
,
with four s
e
ts of
c
hromosom
e
s
,
e
xhi
b
it sup
e
rior growth
r
a
t
e
s
c
omp
a
r
ed
to
d
iploi
d
sp
ec
i
e
s
.
T
h
e
ir
ce
ll
d
ivision
ca
p
ab
iliti
e
s
a
r
e
signifi
ca
ntly high
e
r th
a
n norm
a
l
d
iploi
d
fish
,
r
e
sulting in
a
gr
ea
t
e
r num
be
r of
ce
lls in t
e
tr
a
ploi
d
fish
.
2
.
6
E
m
b
ryog
e
n
e
sis
E
m
b
ryog
e
n
e
sis r
e
f
e
rs to th
e
form
a
tion
a
n
d de
v
e
lopm
e
nt of
e
m
b
ryos
,
be
ginning from th
e
mom
e
nt of
c
on
ce
ption or f
e
rtiliz
a
tion
.
T
his
pro
ce
ss involv
e
s
a
s
e
ri
e
s of st
a
g
e
s m
a
rk
ed b
y
ce
ll
d
ivision
a
n
d
r
e
gul
a
tion
a
t th
e ce
llul
a
r l
e
v
e
l
,
wh
e
r
e ce
lls
a
r
e
known
a
s
e
m
b
ryog
e
ni
c ce
lls
.
Ge
n
e
r
a
lly
,
e
m
b
ryog
e
ni
c ce
lls progr
e
ss through s
e
v
e
r
a
l ph
a
s
e
s
:
a
singl
e
f
e
rtiliz
ed ce
ll
,
b
l
a
stom
e
r
,
b
l
a
stul
a
,
g
a
strul
a
,
n
e
urul
a
,
a
n
d e
v
e
ntu
a
lly th
e
e
m
b
ryo or f
e
tus
.
T
o stu
d
y th
e
s
e
st
a
g
e
s in
e
m
b
ryog
e
n
e
sis
,
r
e
s
ea
r
c
h
e
rs
15
oft
e
n us
e Xe
nopus l
ae
vis frog
e
m
b
ryos
a
s
a
mo
de
l
.
T
h
e
st
a
g
e
s o
b
s
e
rv
ed
in
c
lu
de
th
e
initi
a
l
c
l
ea
v
a
g
e
,
fin
a
l
c
l
ea
v
a
g
e
,
b
l
a
stul
a
form
a
tion
,
a
mphioxus
g
a
strul
a
st
a
g
e
,
yolk plug form
a
tion
,
n
e
ur
a
l fol
d
,
a
n
d
n
e
ur
a
l tu
be
de
v
e
lopm
e
nt
.
2
.
6
.
1
C
l
ea
v
a
g
e P
h
a
s
e A
n
d B
l
a
stul
a
tion
C
l
ea
v
a
g
e a
n
d b
l
a
stul
a
tion
a
r
e
th
e
initi
a
l pro
ce
ss
e
s th
a
t l
ead
to th
e
form
a
tion of
a
n
e
w
,
multi
-
ce
ll
ed
in
d
ivi
d
u
a
l from
a
n ovum
,
or zygot
e
,
whi
c
h
c
ont
a
ins
a
mphinu
c
l
e
i
.
I
n frogs
,
c
l
ea
v
a
g
e
is holo
b
l
a
sti
c
,
tot
a
l
,
a
n
d
un
e
qu
a
l
.
D
uring this pro
ce
ss
,
th
e
first
c
l
ea
v
a
g
e
pl
a
n
e
is m
e
ri
d
ion
a
l
,
follow
ed b
y
a
s
ec
on
d
m
e
ri
d
ion
a
l
c
l
ea
v
a
g
e a
n
d a
thir
d
horizont
a
l
c
l
ea
v
a
g
e
.
T
h
e
horizont
a
l
c
l
ea
v
a
g
e
r
e
sults in th
e
pro
d
u
c
tion of m
ac
rom
e
r
e
s
(
l
a
rg
e
ce
lls
)
a
n
d
mi
c
rom
e
r
e
s
(
sm
a
ll
ce
lls
).
T
his is follow
ed b
y
a
simult
a
n
e
ous
m
e
ri
d
ion
a
l
c
l
ea
v
a
g
e
,
whi
c
h involv
e
s two p
e
rp
e
n
d
i
c
ul
a
r
c
l
ea
v
a
g
e
s
o
cc
urring tog
e
th
e
r
.
T
h
e
fifth
c
l
ea
v
a
g
e
pl
a
n
e
is simult
a
n
e
ous horizont
a
l
,
c
ontinuing until
a ca
vity forms within th
e
stru
c
tur
e
,
c
r
ea
ting
a
hollow
sph
e
ri
ca
l form
.
I
n frogs
,
this
ca
vity is r
e
f
e
rr
ed
to
a
s th
e b
l
a
sto
c
o
e
l
,
fill
ed
with int
e
rn
a
l flui
d a
n
d
surroun
ded b
y
e
pith
e
li
a
l
ce
lls
.
T
his hollow
ba
ll is
known
a
s th
e b
l
a
stul
a
.
2
.
6
.
2
P
h
a
s
e Ga
strul
a
tion
A
s th
e b
l
a
stul
a
progr
e
ss
e
s through
ce
ll
d
ivision
a
n
d
th
e
num
be
r of
ce
lls
in
c
r
ea
s
e
s
,
th
e a
nim
a
l pol
e be
gins to
e
n
c
ir
c
l
e
th
e
v
e
g
e
t
a
l pol
e
through
mov
e
m
e
nt
a
n
d
inv
a
gin
a
tion
,
a
pro
ce
ss
c
ommonly r
e
f
e
rr
ed
to
a
s
g
a
strul
a
tion
.
T
his pro
ce
ss unfol
d
s in
a
sp
ec
ifi
c c
hronologi
ca
l s
e
qu
e
n
ce
:
first
,
th
e
form
a
tion of th
e b
l
a
stopor
e
,
whi
c
h involv
e
s th
e
inv
a
gin
a
tion of
th
e c
h
a
nn
e
l
;
n
e
xt
,
th
e de
v
e
lopm
e
nt of th
e ec
to
de
rm
,
m
e
so
de
rm
,
a
n
d
e
n
d
o
de
rm l
a
y
e
rs
;
a
n
d
fin
a
lly
,
ce
ll migr
a
tion
a
n
d ad
h
e
sion
,
f
ac
ilit
a
t
ed b
y
cad
h
e
rin
a
n
d
int
e
grin
c
ompoun
d
s
.
2
.
6
.
3
P
h
a
s
e Ne
urul
a
tion
16
T
h
e
g
a
strul
a
ph
a
s
e
progr
e
ss
e
s into n
e
urul
a
tion
,
a
pro
ce
ss wh
e
r
e
th
e
n
e
ur
a
l
ec
to
de
rm
,
de
riv
ed
from th
e d
iff
e
r
e
nti
a
tion of th
e ec
to
de
rm
,
be
gins to form th
e
n
e
rvous syst
e
m
.
D
uring n
e
urul
a
tion
,
th
e c
hor
da
m
e
so
de
rm
ac
ts
a
s
a
n in
d
u
ce
r
.
I
n th
e d
ors
a
l p
a
rt of th
e e
m
b
ryo
,
th
e
ec
to
de
rm thi
c
k
e
ns to
c
r
ea
t
e
th
e
n
e
ur
a
l pl
a
t
e
,
whi
c
h th
e
n
de
v
e
lops into
n
e
ur
a
l fol
d
s
a
n
d a
n
e
ur
a
l groov
e
.
T
h
e
s
e
n
e
ur
a
l fol
d
s
e
v
e
ntu
a
lly fus
e
to
form th
e
n
e
ur
a
l tu
be
,
c
ont
a
ining
a
n
e
ur
a
l
ca
n
a
l
.
A
s this o
cc
urs
,
n
e
ur
a
l pi
a
l
ce
lls
d
iff
e
r
e
nti
a
t
e
into n
e
rv
e
g
a
ngli
a
,
e
st
ab
lishing th
e ce
ntr
a
l n
e
rvous
syst
e
m
.
O
n
ce
th
e
s
e de
v
e
lopm
e
nt
a
l st
a
g
e
s
a
r
e c
ompl
e
t
e
,
th
e
org
a
nism
c
ontinu
e
s to grow until
b
irth or h
a
t
c
hing
,
m
a
tur
e
s into
a
n
ad
ult
,
a
n
d
pro
d
u
ce
s g
a
m
e
t
e
s for f
e
rtiliz
a
tion
,
r
e
p
ea
ting th
e c
y
c
l
e
.
2
.
6
.
4
P
h
a
s
e Ga
strul
a
tion
A
s th
e b
l
a
stul
a
progr
e
ss
e
s through
d
ivision
a
n
d ce
ll prolif
e
r
a
tion
,
th
e a
nim
a
l pol
e be
gins to
e
n
c
ir
c
l
e
th
e
v
e
g
e
t
a
l pol
e
through
a
pro
ce
ss of inv
a
gin
a
tion
,
c
ommonly r
e
f
e
rr
ed
to
a
s g
a
strul
a
tion
.
Ga
strul
a
tion unfol
d
s in
a c
hronologi
ca
l s
e
qu
e
n
ce
,
st
a
rting with th
e
form
a
tion of th
e b
l
a
stopor
e
(
inv
a
gin
a
tion
c
h
a
nn
e
l
),
follow
ed b
y th
e
de
v
e
lopm
e
nt of th
e ec
to
de
rm
,
m
e
so
de
rm
,
a
n
d e
n
d
o
de
rm l
a
y
e
rs
.
S
u
b
s
e
qu
e
ntly
,
ce
lls migr
a
t
e a
n
d ad
h
e
r
e
with th
e a
ssist
a
n
ce
of
cad
h
e
rin
a
n
d
int
e
grin
c
ompoun
d
s
.
2
.
6
.
5
P
h
a
s
e Ne
urul
a
tion
T
h
e
g
a
strul
a
ph
a
s
e
progr
e
ss
e
s into n
e
urul
a
tion
,
a
pro
ce
ss wh
e
r
e
th
e
ec
to
de
rm
d
iff
e
r
e
nti
a
t
e
s into n
e
ur
a
l
ec
to
de
rm
a
n
d de
v
e
lops into th
e
n
e
rvous syst
e
m
.
D
uring n
e
urul
a
tion
,
th
e
m
e
so
de
rm
ac
ts
a
s
a
n in
d
u
ce
r
.
O
n
th
e d
ors
a
l si
de
of th
e e
m
b
ryo
,
th
e ec
to
de
rm thi
c
k
e
ns to form th
e
n
e
ur
a
l
pl
a
t
e
,
whi
c
h th
e
n fol
d
s to
c
r
ea
t
e
th
e
n
e
ur
a
l groov
e
,
fl
a
nk
ed b
y n
e
ur
a
l
fol
d
s
.
T
h
e
s
e
fol
d
s fus
e
to form th
e
n
e
ur
a
l tu
be
,
e
n
c
losing th
e
n
e
ur
a
l
ca
vity
.
A
s this pro
ce
ss unfol
d
s
,
n
e
ur
a
l pi
a
ls
de
v
e
lop
,
whi
c
h will
e
v
e
ntu
a
lly giv
e
ris
e
to n
e
rv
e
g
a
ngli
a
.
T
h
e
n
e
ur
a
l tu
be
th
e
n
bec
om
e
s th
e ce
ntr
a
l n
e
rvous
17
syst
e
m
.
F
ollowing th
e
s
e
st
a
g
e
s
,
th
e ce
lls
c
ontinu
e
to grow
a
n
d de
v
e
lop
until th
e
org
a
nism
e
xits th
e
ut
e
rus or
e
gg
,
m
a
tur
e
s
,
pro
d
u
ce
s g
a
m
e
t
e
s
,
a
n
d
th
e c
y
c
l
e be
gins
a
n
e
w
.
18
METHODOLOGY
PRACTICUM
3
.
1
T
ools
T
h
e
syring
e
is us
ed
to inj
ec
t th
e
ov
a
prim hormon
e
into th
e
fish
,
whil
e
th
e
b
u
c
k
e
t s
e
rv
e
s
a
s
a
stor
a
g
e c
ont
a
in
e
r for th
e
fish
.
C
loth is us
ed
to
c
ov
e
r
th
e
fish
’
s h
ead d
uring inj
ec
tion to r
ed
u
ce
str
e
ss
.
T
h
e
tu
b
fi
be
r is wh
e
r
e
th
e b
r
eed
ing fish
a
r
e
k
e
pt
.
T
h
e ae
r
a
tion s
e
tup
,
in
c
lu
d
ing th
e b
low
e
r
,
ro
c
k
ae
r
a
tor
,
a
n
d
hos
e
,
provi
de
s oxyg
e
n for th
e
fish in th
e a
qu
a
rium
.
T
h
e
w
a
t
e
r
ba
th is us
ed
to h
ea
t w
a
t
e
r to th
e de
sir
ed
t
e
mp
e
r
a
tur
e
.
S
tyrofo
a
m
b
ox
e
s
a
n
d
filt
e
r imm
e
rsion
c
ont
a
in
e
rs
a
r
e
us
ed
for h
a
t
c
hing
e
ggs
.
T
h
e
UV
r
ad
i
a
tion
b
ox is us
ed
for sp
e
rm r
ad
i
a
tion
.
A
th
e
rmom
e
t
e
r m
ea
sur
e
s
th
e
t
e
mp
e
r
a
tur
e d
uring h
ea
t sho
c
k in th
e
w
a
t
e
r
ba
th
,
a
n
d
h
ea
t
e
rs
st
ab
iliz
e
th
e
w
a
t
e
r t
e
mp
e
r
a
tur
e d
uring this pro
ce
ss
.
Pe
tri
d
ish
e
s
a
r
e
us
ed
to hol
d e
ggs
a
n
d
sp
e
rm
,
whil
e
th
e a
qu
a
rium s
e
rv
e
s
a
s
a
stor
a
g
e
pl
ace
for
f
e
rtiliz
ed e
ggs
a
n
d
h
a
t
c
hing
.
T
h
e
mi
c
ros
c
op
e
is us
ed
to o
b
s
e
rv
e
th
e
de
v
e
lopm
e
nt of
e
gg
ce
lls
.
Ma
t
e
ri
a
l
:
Ma
l
e a
n
d
f
e
m
a
l
e c
om
e
t fish s
e
rv
e a
s s
a
mpl
e
fish for t
e
sting
.
T
h
e
fish
,
in
c
lu
d
ing th
e
sir fish
,
a
r
e
us
ed a
s s
a
mpl
e
s for
e
v
a
lu
a
tion
.
NaC
l
physiologi
ca
l solution
ac
ts
a
s
a
flui
d
for
d
iluting sp
e
rm
.
T
h
e
hormon
e
O
v
a
prim is us
ed
to stimul
a
t
e
ovul
a
tion in th
e
sp
a
wning f
e
m
a
l
e
fish
a
n
d
to
e
nh
a
n
ce
sp
e
rm pro
d
u
c
tion in th
e
m
a
l
e
fish
,
whi
c
h will th
e
n
be
r
e
l
ea
s
ed
.
3
.
2
P
ro
ced
ur
e P
r
ac
ti
ca
l
W
ork
3
.
3
.
1
P
r
e
p
a
r
a
tion
T
ool
1
.
Wa
sh
a
qu
a
rium until
c
l
ea
n
.
2
.
Pa
ir inst
a
ll
a
tion
ae
r
a
tion so th
a
t works with
G
oo
d
.
19
3
.
3
.
2
S
p
a
wning
A
rtifi
c
i
a
l
C
hoos
e
th
e
p
a
r
e
nt fish to
be
us
ed
in th
e
pr
ac
ti
c
um
,
s
e
p
a
r
a
ting
th
e
m
b
y g
e
n
de
r
.
Ad
minist
e
r ov
a
prim inj
ec
tions to
b
oth m
a
l
e a
n
d
f
e
m
a
l
e
p
a
r
e
nts
,
with
a d
os
a
g
e
of
0
.
4
ml
/
kg for f
e
m
a
l
e
s
a
n
d
0
.
1
ml
/
kg for m
a
l
e
s
.
Pe
rform sp
e
rm stripping on th
e
m
a
l
e
p
a
r
e
nts
a
n
d
e
gg stripping on th
e
f
e
m
a
l
e
p
a
r
e
nts following ovul
a
tion
.
3
.
3
.
3
H
y
b
ri
d
iz
a
tion
1
.
D
ilut
e
th
e
sp
e
rm pro
d
u
ced b
y th
e
m
a
l
e
p
a
r
e
nt using
a NaC
l solution
.
P
l
ace
th
e
sp
e
rm into
a Pe
tri
d
ish
.
A
pply th
e
sp
e
rm to th
e
f
e
m
a
l
e
c
om
e
t fish
a
n
d c
oll
ec
t it in th
e Pe
tri
d
ish
.
P
ro
ceed
with f
e
rtilizing th
e
c
om
e
t fish
e
ggs with th
e
gol
d
fish sp
e
rm
.
F
in
a
lly
,
d
istri
b
ut
e
th
e
f
e
rtiliz
ed e
ggs onto th
e
pr
e
p
a
r
ed
h
a
t
c
hing filt
e
r
.
3
.
3
.
4
G
ynog
e
n
e
sis
1
D
ilut
e
th
e
sp
e
rm pro
d
u
ced b
y th
e
m
a
l
e
p
a
r
e
nt using
a NaC
l
solution
.
P
l
ace
th
e d
ilut
ed
sp
e
rm in
a Pe
tri
d
ish
a
n
d
irr
ad
i
a
t
e
it for
10
-
15
minut
e
s
.
P
ro
ceed
with f
e
rtiliz
a
tion
b
y
c
om
b
ining th
e
irr
ad
i
a
t
ed
sp
e
rm with th
e e
ggs of
a
f
e
m
a
l
e c
om
e
t fish
.
A
ft
e
r
f
e
rtiliz
a
tion
,
whi
c
h l
a
sts for
2
minut
e
s wh
e
n th
e e
m
b
ryo is in th
e
m
e
iosis
II
ph
a
s
e
,
a
pply
a
h
ea
t sho
c
k to th
e
f
e
rtiliz
ed e
ggs
(
still in
m
e
iosis
II
)
b
y imm
e
rsing th
e
m in
a
styrofo
a
m
c
ont
a
in
e
r fill
ed
with
w
a
t
e
r
a
t
40
°
C
for
2
minut
e
s
.
3
.
3
.
5
T
riploi
d
iz
a
tion
1
T
h
e
sp
e
rm pro
d
u
ced b
y th
e
m
a
l
e
p
a
r
e
nt is
d
ilut
ed
using
a NaC
l solution
.
T
h
e
sp
e
rm is th
e
n pl
aced
in
a Pe
tri
d
ish
.
Fe
rtiliz
a
tion is
ca
rri
ed
out
b
y
c
om
b
ining th
e
sp
e
rm with th
e e
ggs from
a
f
e
m
a
l
e c
om
e
t fish
.
T
h
e
20
f
e
rtiliz
ed e
ggs
a
r
e a
llow
ed
to r
e
m
a
in un
d
istur
bed
for
2
minut
e
s
.
A
ft
e
r
this
,
th
e
f
e
rtiliz
ed e
ggs
a
r
e
su
b
j
ec
t
ed
to
a
h
ea
t sho
c
k in
a
w
a
t
e
r
ba
th
a
t
40
°
C
for
2
minut
e
s
.
F
in
a
lly
,
th
e e
ggs
a
r
e
spr
ead
in
a
n
a
qu
a
rium th
a
t h
a
s
bee
n pr
e
p
a
r
ed
for th
e
m
.
3
.
3
.
6
E
m
b
ryog
e
n
e
sis
1
.
P
r
e
p
a
r
e
th
e
mi
c
ros
c
op
e
w
a
nt to us
ed
2
.
P
r
e
p
a
r
e
s
a
mpl
e W
hi
c
h w
a
nt to o
b
s
e
rv
ed
with t
a
k
e
from
eac
h
eac
h tr
ea
tm
e
nt gynog
e
n
e
sis
,
triploi
d
iz
a
tion
a
n
d
hy
b
ri
d
iz
a
tion
.
3
.
3
.
7
Ma
int
e
n
a
n
ce La
rv
ae
Ce
ll
e
gg
e
xp
e
ri
e
n
ce dea
th
a
n
d N
o
de
v
e
lop
bec
om
e
l
a
rv
ae
so th
a
t w
e ca
nnot
ca
rry out pr
e
vious l
a
rv
a
l m
a
int
e
n
a
n
ce
r
ec
omm
e
n
ded
.
3
.
3
Me
tho
d P
r
ac
ti
c
um
T
o o
b
s
e
rv
e
th
e e
ff
ec
ts of thr
ee
tr
ea
tm
e
nts
—
hy
b
ri
d
iz
a
tion
,
gynog
e
n
e
sis
,
a
n
d
triploi
d
iz
a
tion
—
s
e
v
e
r
a
l pr
e
p
a
r
a
tion st
e
ps
a
r
e
r
e
quir
ed
.
F
or hy
b
ri
d
iz
a
tion
,
first
d
ilut
e
e
xisting sp
e
rm with
NaC
l in
a Pe
tri
d
ish
.
T
h
e
n
,
strip th
e
f
e
m
a
l
e c
om
e
t fish
b
y
pl
ac
ing it in
a Pe
tri
d
ish
c
ont
a
ining th
e
sp
e
rm
.
Fe
rtiliz
e
th
e e
ggs from th
e c
om
e
t
fish
b
y mixing gol
d
fish sp
e
rm with th
e
m
,
a
n
d
pl
ace
th
e
mixtur
e
in
a
n
a
qu
a
rium
.
I
n
gynog
e
n
e
sis
,
d
ilut
e
th
e
sp
e
rm with
NaC
l
,
th
e
n irr
ad
i
a
t
e
it for
10
-
15
minut
e
s
.
S
trip
th
e
f
e
m
a
l
e c
om
e
t fish
,
pl
ace
th
e
irr
ad
i
a
t
ed
sp
e
rm in th
e d
ish with th
e e
ggs
,
a
n
d
in
c
u
ba
t
e
in
a
n
a
qu
a
rium for
40
minut
e
s
.
A
ft
e
rw
a
r
d
,
h
ea
t sho
c
k th
e
s
a
mpl
e
s
a
t
40
°
C
for
2
minut
e
s
,
th
e
n r
e
turn th
e
m to th
e a
qu
a
rium
.
F
or triploi
d
iz
a
tion
,
d
ilut
e
th
e
sp
e
rm with
NaC
l
,
strip th
e
f
e
m
a
l
e
fish
,
a
n
d add
th
e
sp
e
rm
.
Le
t it sit for
2
minut
e
s
,
th
e
n h
ea
t sho
c
k
a
t
40
°
C
for
2
minut
e
s
,
a
n
d
pl
ace
it in
a
n
a
qu
a
rium
.
F
in
a
lly
,
pr
e
p
a
r
e
th
e
n
ece
ss
a
ry tools
,
in
c
lu
d
ing
a
mi
c
ros
c
op
e
,
to o
b
s
e
rv
e
th
e c
h
a
ng
e
s in th
e
fish
e
gg
ce
lls
.
O
n
ce a
ll tr
ea
tm
e
nts
a
r
e
s
e
t
,
o
b
s
e
rv
e
th
e e
ggs from
eac
h
tr
ea
tm
e
nt
—
gynog
e
n
e
sis
,
triploi
d
iz
a
tion
,
a
n
d
hy
b
ri
d
iz
a
tion
—
to
a
ss
e
ss th
e
r
e
sults
.
T
h
e
pr
ac
ti
c
um us
e
s
a
n
e
xp
e
rim
e
nt
a
l
a
ppro
ac
h with v
a
rious tr
ea
tm
e
nts in
c
lu
d
ing
stripping
,
d
ilution
,
r
ad
i
a
tion
,
a
n
d
h
ea
t sho
c
k
.
21
3
.
4
De
sign
P
r
ac
ti
c
um
3
.
5
.
1
FR
FR
or
f
e
rtiliz
a
tion r
a
t
e
is th
e de
gr
ee
of
e
gg f
e
rtiliz
a
tion
.
De
gr
ee
o
b
s
e
rv
a
tion
c
on
ce
ption
e
gg
(
FR
)
W
hi
c
h
d
on
e a
ft
e
r
c
on
ce
ption
e
gg on
pro
ce
ss gynog
e
n
e
sis
,
hy
b
ri
d
iz
a
tion
,
a
n
d
triploi
d
iz
a
tion is
c
ompl
e
t
e d
on
e
.
I
nform
a
tion
:
FR
:
De
gr
ee
s f
e
rtiliz
a
tion
e
gg
(
%
)
P
:
N
um
be
r of
e
ggs s
a
mpl
e
PO
:
a
mount th
e e
gg f
e
rtiliz
ed
3
.
5
.
2
HR
HR
or
h
a
t
c
hing r
a
t
e
is th
e de
gr
ee
of
e
gg h
a
t
c
hing
.
Ob
s
e
rv
a
tion
de
gr
ee
s
E
gg h
a
t
c
hing is
ca
rri
ed
out wh
e
n th
e e
m
b
ryo is
17
-
20
hours from
f
e
rtiliz
a
tion
e
gg
.
HR
(
%
) =
x
100
%
I
nform
a
tion
:
HR
:
De
gr
ee
s h
a
t
c
hing
e
gg
PT
:
A
mount
e
gg
W
hi
c
h
h
a
t
c
h
P
o
:
N
um
be
r of
e
ggs
f
e
rtiliz
ed
FR
(
%
) =
x
100
%
22
3
.
5
.
3
SR La
rv
ae
SR
or
surviv
a
l r
a
t
e
is th
e de
gr
ee
of fish surviv
a
l
.
Ob
s
e
rv
a
tion
T
h
e
de
gr
ee
of surviv
a
l of fish is
ca
rri
ed
out only for th
e
pro
ce
ss
e
s of
gynog
e
n
e
sis
,
hy
b
ri
d
iz
a
tion
,
A
n
d
triploi
d
iz
a
tion
a
ft
e
r l
a
rv
ae a
g
ed
fish s
e
v
e
n
da
y
.
I
nform
a
tion
:
SR
:
C
ontinuity lif
e
fish
d
uring pr
ac
ti
c
um
N
t
:
N
um
be
r of fish on
e
n
d
pr
ac
ti
c
um
N
o
:
N
um
be
r of fish on
be
ginning pr
ac
ti
c
um
3
.
5
Da
t
a a
n
a
lysis
Da
t
a
whi
c
h is o
b
t
a
in
ed
pr
e
s
e
nt
ed
in th
e
form of
ca
l
c
ul
a
tions
a
n
d
a
n
a
lyz
ed de
s
c
riptiv
e
ly
,
n
a
m
e
ly
b
y
c
omp
a
ring
e
xp
e
rim
e
nt
a
l r
e
sults with
th
e
lit
e
r
a
tur
e W
hi
c
h r
e
l
a
t
ed
to hy
b
ri
d
iz
a
tion
,
triploi
d
iz
a
tion
a
n
d
gynog
e
n
e
sis
.
SR
(
%
) =
x
100
%
23
CHAPTER IV
RESULTS AND DISCUSSION
4
.
1
S
p
a
wning
A
rtifi
c
i
a
l
A
rtifi
c
i
a
l sp
a
wning involv
e
s thr
ee
prim
a
ry t
ec
hniqu
e
s
:
hy
b
ri
d
iz
a
tion
,
gynog
e
n
e
sis
,
a
n
d
triploi
d
iz
a
tion
.
Eac
h t
ec
hniqu
e
is
a
im
ed a
t
ac
hi
e
ving
de
sir
ed
out
c
om
e
s in t
e
rms of growth
a
n
d
physi
ca
l
c
h
a
r
ac
t
e
risti
c
s
.
T
h
e
s
e
m
e
tho
d
s
a
ll utiliz
e a c
ommon
a
ppro
ac
h
—
e
xt
e
rn
a
l sp
a
wning
,
p
e
rform
ed
outsi
de
th
e
fish
'
s
b
o
d
y
.
P
rior to
a
pplying th
e
s
e
t
ec
hniqu
e
s
,
f
e
m
a
l
e
fish
a
r
e
inj
ec
t
ed
with
O
v
a
prim hormon
e
in th
e e
v
e
ning
,
whi
c
h h
e
lps stimul
a
t
e
th
e
growth
of
e
gg
ce
lls to
e
nh
a
n
ce
th
e
ir
de
v
e
lopm
e
nt
.
4
.
2
H
y
b
ri
d
iz
a
tion
4
.
2
.
1
Re
sults
O
ur group
c
oll
ec
t
ed a
tot
a
l of
615
e
ggs through th
e
stripping pro
ce
ss
,
out of whi
c
h
500
e
ggs w
e
r
e
su
cce
ssfully f
e
rtiliz
ed
whil
e
th
e
r
e
m
a
ining
on
e
s
d
i
d
not surviv
e
.
T
o
d
iff
e
r
e
nti
a
t
e be
tw
ee
n
dead a
n
d
liv
e e
ggs
without using
a
mi
c
ros
c
op
e
,
on
e ca
n o
b
s
e
rv
e
th
e
physi
ca
l
a
pp
ea
r
a
n
ce
:
unf
e
rtiliz
ed e
ggs
a
r
e
p
a
l
e
whit
e
,
wh
e
r
ea
s f
e
rtiliz
ed e
ggs
a
pp
ea
r y
e
llow
or y
e
llowish
-
c
l
ea
r
.
T
h
e
f
e
rtiliz
a
tion r
a
t
e
(
FR
)
for our group w
a
s
ca
l
c
ul
a
t
ed a
s follows
:
FR
(
%
) = (
N
um
be
r of f
e
rtiliz
ed e
ggs
/
T
ot
a
l
e
ggs
) ×
100
%
= (
500
/
615
)
×
100
%
=
81
.
3
%
O
n th
e
oth
e
r h
a
n
d
,
th
e
h
a
t
c
hing r
a
t
e
(
HR
)
w
a
s
de
t
e
rmin
ed
to
be
:
HR
(
%
) = (
N
um
be
r of h
a
t
c
h
ed e
ggs
/
N
um
be
r of f
e
rtiliz
ed e
ggs
) ×
100
%
= (
0
/
500
) ×
100
%
=
0
%
24
4
.
2
.
2
D
is
c
ussion
H
y
b
ri
d
iz
a
tion is
a
t
ec
hniqu
e
wh
e
r
e
two
d
iff
e
r
e
nt typ
e
s of fish
a
r
e
c
ross
ed e
xt
e
rn
a
lly
,
outsi
de
th
e
fish
'
s
b
o
d
y
,
b
y m
a
ting with fish th
a
t
h
a
v
e de
sir
ab
l
e
tr
a
its to
e
nh
a
n
ce
g
e
n
e
ti
c c
h
a
r
ac
t
e
risti
c
s
,
a
n
d
it
ca
n
involv
e d
iff
e
r
e
nt sp
ec
i
e
s
.
T
h
e
hy
b
ri
d
iz
a
tion
a
tt
e
mpts with
c
om
e
t
a
n
d
gol
d
fish w
e
r
e
unsu
cce
ssful
d
u
e
to s
e
v
e
r
a
l f
ac
tors
:
th
e
sp
e
rm
ce
lls
d
i
d
not f
e
rtiliz
e
th
e e
gg
ce
lls
,
th
e e
ggs w
e
r
e
oft
e
n r
e
l
ea
s
ed
a
n
d
pl
aced
in
a
p
e
tri
d
ish
a
w
a
y from th
e a
qu
a
rium
,
d
isrupting th
e
ongoing pro
ce
ss
e
s
,
a
n
d
th
e
inj
ec
tion pro
ce
ss
a
lso
a
ff
ec
t
ed e
gg
ce
ll
qu
a
lity
.
O
ur group
’
s
da
t
a
show
ed a
f
e
rtiliz
a
tion r
a
t
e
of
89
.
1
%
b
ut
a
h
a
t
c
hing r
a
t
e
of
0
%
.
T
h
e
high f
e
rtiliz
a
tion r
a
t
e
w
a
s
ac
hi
e
v
ed
beca
us
e
w
e
follow
ed
prop
e
r pro
ced
ur
e
s
,
in
c
lu
d
ing
ad
minist
e
ring
th
e
hormon
e
ov
a
prim to stimul
a
t
e e
gg
de
v
e
lopm
e
nt in th
e
f
e
m
a
l
e
fish with th
e c
orr
ec
t
d
os
a
g
e acc
or
d
ing to th
e
ir w
e
ight
.
Add
ition
a
lly
,
th
e
stripping pro
ce
ss involv
ed
pl
ac
ing
e
ggs into
a
r
ece
pt
ac
l
e
a
lr
ead
y
c
ont
a
ining sp
e
rm
d
ilut
ed
with
NaC
l
.
D
ir
ec
tly intro
d
u
c
ing
s
a
mpl
e
s into
a
n
a
qu
a
rium th
a
t
'
s
ade
qu
a
t
e
ly fill
ed
with w
a
t
e
r
a
n
d
e
quipp
ed
with
ae
r
a
tion
ca
n som
e
tim
e
s l
ead
to f
a
ilur
e
.
T
his m
a
y
be
d
u
e
to fun
da
m
e
nt
a
l issu
e
s
,
su
c
h
a
s fr
e
qu
e
nt r
e
mov
a
l of s
a
mpl
e
s
from th
e a
qu
a
rium
,
whi
c
h hin
de
rs
e
gg
de
v
e
lopm
e
nt
.
I
n som
e ca
s
e
s
,
e
ggs m
a
y
de
v
e
lop
b
ut st
a
ll
a
t
ce
rt
a
in st
a
g
e
s
d
u
e
to
e
xt
e
rn
a
l f
ac
tors
,
su
c
h
a
s fr
e
qu
e
nt r
e
mov
a
l of s
a
mpl
e
s
ca
using th
e a
qu
a
rium to
bec
om
e d
irty
a
n
d c
ont
a
min
a
t
ed
.
O
ur group
e
n
c
ount
e
r
ed d
iffi
c
ulti
e
s
with hy
b
ri
d
iz
ed
s
a
mpl
e
s
d
u
e
to th
e c
h
a
ll
e
ng
e
of
e
xtr
ac
ting
e
ggs
from th
e Pe
tri
d
ish
,
r
e
sulting in
a
high f
a
ilur
e
r
a
t
e
.
Add
ition
a
lly
,
c
ont
a
min
a
tion from
e
xt
e
rn
a
l
a
ir
a
n
d
h
a
n
d
ling furth
e
r
e
x
ace
r
ba
t
ed
th
e
pro
b
l
e
m
.
T
o improv
e
su
cce
ss r
a
t
e
s
,
it
'
s
e
ss
e
nti
a
l to
ca
r
e
fully
m
a
n
a
g
e e
gg
e
xtr
ac
tion from s
a
mpl
e
s to
a
voi
d d
istur
b
ing th
e
origin
a
l sp
ec
im
e
ns
.
25
4
.
3
G
ynog
e
n
e
sis
4
.
3
.
1
Re
sults
We c
oll
ec
t
ed
753
e
ggs from th
e
stripping
a
n
d
f
e
rtiliz
a
tion pro
ce
ss
,
of
whi
c
h
677
w
e
r
e
su
cce
ssfully f
e
rtiliz
ed
,
whil
e
th
e
r
e
st p
e
rish
ed
.
We
de
t
e
rmin
ed
f
e
rtiliz
a
tion su
cce
ss
b
y
e
x
a
mining th
e
physi
ca
l
a
pp
ea
r
a
n
ce
of th
e e
ggs
:
f
e
rtiliz
ed e
ggs
a
pp
ea
r
ed
y
e
llow or
c
l
ea
r
,
whil
e
non
-
f
e
rtiliz
ed e
ggs w
e
r
e
p
a
l
e a
n
d
whit
e
.
T
h
e
f
e
rtiliz
a
tion r
a
t
e
w
a
s
ca
l
c
ul
a
t
ed a
s follows
:
FR
(
%
) =
X
100
%
=
X
100
%
=
89
.
9
%
T
h
e
h
a
t
c
hing r
a
t
e
for th
e
gynog
e
n
e
sis tr
ea
tm
e
nt w
a
s
:
HR
(
%
) =
X
100
%
=
X
100
%
=
0
%
4
.
3
.
2
D
is
c
ussion
G
ynog
e
n
e
sis is
a
n
a
rtifi
c
i
a
l r
e
pro
d
u
c
tiv
e
m
e
tho
d
th
a
t r
e
quir
e
s no
m
a
l
e
g
a
m
e
t
e
s for th
e
form
a
tion of zygot
e
s
;
inst
ead
,
m
a
l
e
g
a
m
e
t
e
s
a
r
e
only us
ed
to stimul
a
t
e
th
e de
v
e
lopm
e
nt of
e
gg
ce
lls
.
I
n
gynog
e
n
e
sis
,
f
e
m
a
l
e
s
e
x
ce
lls form
a
zygot
e
without
a
ny g
e
n
e
ti
c
c
ontri
b
ution from m
a
l
e
g
a
m
e
t
e
s
.
T
his pro
ce
ss involv
e
s irr
ad
i
a
ting
th
e e
ggs with
UV
r
a
ys to
deac
tiv
a
t
e
th
e
g
e
n
e
s
,
follow
ed b
y
a
h
ea
t
sho
c
k tr
ea
tm
e
nt
.
P
rior to this
,
f
e
m
a
l
e
fish
a
r
e
inj
ec
t
ed
with
a
su
b
st
a
n
ce
to
e
nh
a
n
ce
th
e e
ggs
'
ca
p
ac
ity for
de
v
e
lopm
e
nt
.
A
ft
e
r
UV
irr
ad
i
a
tion
,
sp
e
rm motility is
a
ss
e
ss
ed
to
e
nsur
e
it is fr
ee
of g
e
n
e
ti
c
m
a
t
e
ri
a
l
.
I
f th
e
sp
e
rm is motil
e a
n
d
l
ac
ks g
e
n
e
ti
c
m
a
t
e
ri
a
l
,
it
ca
n
be
us
ed
for furth
e
r gynog
e
n
e
sis tr
ea
tm
e
nt
.
I
f th
e
sp
e
rm is non
-
motil
e
or
dead
,
gynog
e
n
e
sis will not o
cc
ur
a
n
d
only norm
a
l
d
iploi
d
iz
a
tion
will t
a
k
e
pl
ace
.
M
otil
e
sp
e
rm
ce
lls without g
e
n
e
ti
c
m
a
t
e
ri
a
l
a
r
e
mix
ed
with
e
gg
ce
lls to
ac
hi
e
v
e
f
e
rtiliz
a
tion
.
T
h
e
f
e
rtiliz
ed e
ggs
a
r
e
th
e
n su
b
j
ec
t
ed
to
a
h
ea
t sho
c
k
a
t
40
°
C
for
2
minut
e
s to pr
e
v
e
nt th
e
loss of f
e
m
a
l
e c
hromosom
e
s
d
uring
e
gg
de
v
e
lopm
e
nt
,
ultim
a
t
e
ly
pro
d
u
c
ing
d
iploi
d a
n
d
homozygous zygot
e
s
,
a
s gynog
e
n
e
ti
c
26
e
m
b
ryos
a
r
e
typi
ca
lly h
a
ploi
d
.
O
ur group
'
s o
b
s
e
rv
a
tions r
e
v
ea
l
ed
th
a
t th
e
f
e
rtiliz
a
tion r
a
t
e
w
a
s
89
.
9
%
,
b
ut th
e e
gg h
a
t
c
hing r
a
t
e
w
a
s
0
%
.
O
v
e
r
a
15
-
minut
e
o
b
s
e
rv
a
tion p
e
rio
d
,
c
h
a
ng
e
s w
e
r
e
not
ed
,
a
n
d b
y th
e
30
-
minut
e
m
a
rk
,
th
e e
ggs
a
pp
ea
r
ed
un
de
v
e
lop
ed
.
T
h
e
y w
e
r
e
roun
d
with
a
da
rk
c
or
e
,
in
d
i
ca
ting th
a
t th
e
y w
e
r
e dead
.
T
h
e
z
e
ro h
a
t
c
hing r
a
t
e
w
a
s
a
ttri
b
ut
ed
to s
e
v
e
r
a
l f
ac
tors
,
in
c
lu
d
ing th
e
us
e
of
a
n ol
d
p
e
tri
d
ish
,
whi
c
h l
ed
to
c
ont
a
min
a
tion from
e
xt
e
rn
a
l sour
ce
s
.
F
r
e
qu
e
nt
r
e
mov
a
l of th
e d
ish from th
e a
qu
a
rium
d
istur
bed
th
e e
ggs
,
pr
e
v
e
nting th
e
m from
de
v
e
loping prop
e
rly
a
n
d
ultim
a
t
e
ly l
ead
ing to
th
e
ir
dea
th
.
4
.
4
T
riploi
d
iz
a
tion
4
.
4
.
1
Re
sults
O
ut of th
e
tot
a
l
578
e
ggs o
b
t
a
in
ed
from th
e
stripping
a
n
d
f
e
rtiliz
a
tion pro
ce
ss
,
515
w
e
r
e
su
cce
ssfully f
e
rtiliz
ed
whil
e
th
e
r
e
st
w
e
r
e
not vi
ab
l
e
.
T
h
e
vi
ab
ility of th
e e
ggs
ca
n
be de
t
e
rmin
ed b
y th
e
ir
physi
ca
l
a
pp
ea
r
a
n
ce
:
f
e
rtiliz
ed e
ggs
a
r
e
typi
ca
lly y
e
llow or
c
l
ea
r
,
wh
e
r
ea
s unf
e
rtiliz
ed e
ggs
a
pp
ea
r p
a
l
e a
n
d
v
e
ry whit
e
.
T
h
e
f
e
rtiliz
a
tion r
a
t
e
(
FR
)
is
ca
l
c
ul
a
t
ed a
s follows
:
FR
(
%
) = (
num
be
r of
f
e
rtiliz
ed e
ggs
/
tot
a
l num
be
r of
e
ggs
) ×
100
%
= (
515
/
578
) ×
100
%
=
89
.
1
%
.
T
h
e
h
a
t
c
hing r
a
t
e
(
HR
)
is
ca
l
c
ul
a
t
ed a
s
:
HR
(
%
) = (
num
be
r
of h
a
t
c
h
ed e
ggs
/
tot
a
l num
be
r of
e
ggs
) ×
100
%
=
0
%
.
4
.
4
.
2
D
is
c
ussion
T
riploi
d
iz
a
tion is
a
t
ec
hniqu
e
us
ed
to inhi
b
it th
e
form
a
tion of s
e
x
ce
lls in
fish
,
a
llowing th
e
m to grow f
a
st
e
r
beca
us
e
th
e e
n
e
rgy oth
e
rwis
e
us
ed
for s
e
x
ce
ll
de
v
e
lopm
e
nt is r
ed
ir
ec
t
ed
tow
a
r
d
growth
.
T
his pro
ce
ss
involv
e
s
a
pplying h
ea
t sho
c
k to
d
isrupt m
e
iosis
II
,
typi
ca
lly
d
on
e
within
th
e
first to thir
d
minut
e
s
a
ft
e
r f
e
rtiliz
a
tion
.
I
f th
e
h
ea
t sho
c
k is su
cce
ssful
,
th
e
r
e
sulting
e
m
b
ryo will h
a
v
e
thr
ee
s
e
ts of
c
hromosom
e
s
.
H
ow
e
v
e
r
,
in
our
e
xp
e
rim
e
nts
,
a
ll
e
ggs su
b
j
ec
t
ed
to triploi
d
iz
a
tion tr
ea
tm
e
nt r
e
sult
ed
in tot
a
l mort
a
lity
,
with
a
0
%
h
a
t
c
hing r
a
t
e
.
T
his f
a
ilur
e ca
n
be a
ttri
b
ut
ed
27
to s
e
v
e
r
a
l f
ac
tors
,
in
c
lu
d
ing ov
e
r
c
row
d
ing in th
e a
qu
a
rium
,
fr
e
qu
e
nt
d
istur
ba
n
ce
s
,
a
n
d d
irty w
a
t
e
r th
a
t m
a
y h
a
v
e
hin
de
r
ed
th
e e
ggs
'
de
v
e
lopm
e
nt
.
Add
ition
a
lly
,
poor tim
e
m
a
n
a
g
e
m
e
nt
a
n
d e
xposur
e
to
a
ir
ca
n furth
e
r imp
a
ir
e
gg
de
v
e
lopm
e
nt
,
l
ead
ing to
c
ont
a
min
a
tion
a
n
d a
l
ac
k of oxyg
e
n
,
ultim
a
t
e
ly
ca
using th
e e
ggs to
d
i
e
.
4
.
5
E
m
b
ryog
e
n
e
4
.
5
.
1
D
is
c
ussion
E
m
b
ryog
e
n
e
sis is th
e
pro
ce
ss of
de
v
e
lopm
e
nt
a
n
d
form
a
tion
th
a
t o
cc
urs from th
e e
m
b
ryo st
a
g
e
,
involving v
a
rious
ce
ll
de
v
e
lopm
e
nt st
a
g
e
s following f
e
rtiliz
a
tion
.
A
ft
e
r
a
pproxim
a
t
e
ly
thr
ee
hours of o
b
s
e
rv
a
tion un
de
r
a
mi
c
ros
c
op
e
,
w
e
not
ed c
h
a
ng
e
s
in th
e e
gg
ce
lls
,
in
c
lu
d
ing hy
b
ri
d
iz
a
tion
,
triploi
d
iz
a
tion
,
a
n
d
gynog
e
n
e
sis
,
until
a
ll th
e
o
b
s
e
rv
ed e
ggs ultim
a
t
e
ly
d
i
ed
.
Ob
s
e
rv
a
tions w
e
r
e c
on
d
u
c
t
ed e
v
e
ry
15
minut
e
s for
a
tot
a
l of thr
ee
hours on
eac
h
e
gg pl
aced
in
a Pe
tri
d
ish
,
r
e
v
ea
ling th
a
t
c
h
a
ng
e
s
o
cc
urr
ed d
uring th
e
first
15
minut
e
s
.
B
y
13
:
33
,
e
ggs su
b
j
ec
t
ed
to
gynog
e
n
e
sis show
ed
no furth
e
r
c
h
a
ng
e
s
a
n
d
w
e
r
e
m
a
rk
ed a
s
dead
,
in
d
i
ca
t
ed b
y
a
roun
ded
sh
a
p
e a
n
d b
l
ac
k
d
is
c
olor
a
tion in th
e
mi
dd
l
e
.
S
imil
a
rly
,
b
y
12
:
11
,
e
ggs un
de
rgoing triploi
d
iz
a
tion
a
lso
e
xhi
b
it
ed
no
furth
e
r
c
h
a
ng
e
s
a
n
d
w
e
r
e dee
m
ed dead
,
showing only
a
roun
d
sh
a
p
e a
n
d b
l
ac
k
c
olor
a
tion
.
B
y
13
:
08
,
e
ggs in th
e
hy
b
ri
d
iz
a
tion
tr
ea
tm
e
nt show
ed
no furth
e
r
c
h
a
ng
e
s
,
pr
e
s
e
nting th
e
s
a
m
e
c
h
a
r
ac
t
e
risti
c
s
a
s thos
e
in th
e
oth
e
r tr
ea
tm
e
nts
—
roun
d
form with
a
b
l
ac
k
ce
nt
e
r
.
4
.
6
S
u
cce
ss
S
p
a
wning
S
u
cce
ss in
a
rtifi
c
i
a
l sp
a
wning
ca
n
be
influ
e
n
ced b
y s
e
v
e
r
a
l
f
ac
tors in
c
lu
d
ing p
a
r
e
nt s
e
l
ec
tion
,
inj
ec
tion
,
str
ea
ming pro
ce
ss
,
w
a
t
e
r
c
on
d
itions
,
a
n
d
tr
ea
tm
e
nt m
e
tho
d
s
.
Pa
r
e
nt s
e
l
ec
tion shoul
d
28
be
thorough
,
e
nsuring th
a
t th
e c
hos
e
n fish h
a
v
e
th
e
pot
e
nti
a
l to
pro
d
u
ce
sup
e
rior offspring
.
F
or inst
a
n
ce
,
in our group
’
s pr
ac
ti
ce
,
w
e
s
e
l
ec
t
ed
physi
ca
lly m
a
tur
e c
om
e
t fish
,
i
de
ntifi
ab
l
e b
y th
e
ir
e
nl
a
rg
ed
stom
ac
hs
a
n
d ab
un
da
nt
e
gg
ce
lls
.
We
inj
ec
t
ed
th
e
s
e
fish
with ov
a
prim mix
ed
with
d
istill
ed
w
a
t
e
r
,
t
a
rg
e
ting th
e a
r
ea
n
e
xt to
th
e d
ors
a
l fin
.
A
ft
e
r inj
ec
tion
,
w
e a
llow
ed a da
y for th
e e
ggs to
de
v
e
lop
,
th
e
n f
e
rtiliz
ed
th
e
m with m
a
l
e
sp
e
rm
acc
or
d
ing to
a
rtifi
c
i
a
l
sp
a
wning pro
ced
ur
e
s
.
U
nfortun
a
t
e
ly
,
our group
’
s
a
tt
e
mpt r
e
sult
ed
in f
a
ilur
e
,
a
s non
e
of th
e e
ggs h
a
t
c
h
ed
su
cce
ssfully
.
CONCLUSION A
n
d
SUGGESTION
T
h
e
o
b
s
e
rv
a
tions l
ead
to th
e c
on
c
lusion th
a
t hormon
e
s
,
sp
ec
ifi
ca
lly ov
a
prim
,
a
r
e
us
ed
to stimul
a
t
e
th
e
growth of f
e
m
a
l
e
fish
e
ggs
.
T
his
a
llows us to i
de
ntify
a
n
d d
iff
e
r
e
nti
a
t
e be
tw
ee
n f
e
m
a
l
e
fish th
a
t
a
r
e
r
ead
y to sp
a
wn
a
n
d
thos
e
th
a
t
a
r
e
not
.
I
t
a
lso h
e
lps in
m
a
st
e
ring th
e
prop
e
r inj
ec
tion
a
n
d
stripping t
ec
hniqu
e
s
.
T
h
e a
im of
th
e
thr
ee a
rtifi
c
i
a
l sp
a
wning m
e
tho
d
s is to
ac
hi
e
v
e d
iff
e
r
e
nt r
e
sults
c
omp
a
r
ed
to norm
a
l sp
a
wning
,
su
c
h
a
s
e
nh
a
n
ced
growth
a
n
d
sup
e
rior physi
ca
l tr
a
its in fish
.
H
y
b
ri
d
iz
a
tion
,
for inst
a
n
ce
,
involv
e
s
m
a
ting two fish with
de
sir
ab
l
e
tr
a
its to improv
e
offspring qu
a
lity
.
T
riploi
d
iz
a
tion is
a
t
ec
hniqu
e
us
ed
to inhi
b
it g
a
m
e
t
e ce
ll growth
,
thus r
ed
ir
ec
ting
e
n
e
rgy tow
a
r
d
s f
a
st
e
r physi
ca
l growth
.
G
ynog
e
n
e
sis involv
e
s forming zygot
e
s from f
e
m
a
l
e
g
a
m
e
t
e
s
without m
a
l
e
g
a
m
e
t
e
s
'
c
ontri
b
ution
,
r
e
lying on m
a
l
e
g
a
m
e
t
e
s sol
e
ly
to stimul
a
t
e e
gg
ce
ll growth
.
T
o o
b
t
a
in sup
e
rior r
e
sults
,
high
-
qu
a
lity p
a
r
e
nt fish
a
r
e e
ss
e
nti
a
l
,
a
n
d ca
r
e
ful h
a
n
d
ling
,
acc
ur
ac
y
,
a
n
d
ad
h
e
r
e
n
ce
to pro
ced
ur
a
l st
a
g
e
s
a
r
e
r
e
quir
ed
for su
cce
ssful
out
c
om
e
s in hy
b
ri
d
iz
a
tion
,
gynog
e
n
e
sis
,
a
n
d
triploi
d
iz
a
tion m
e
tho
d
s
.
I
n t
e
rms of sugg
e
stions
,
c
h
a
ll
e
ng
e
s in th
e
pr
ac
ti
c
um in
c
lu
de
th
e
n
eed
for
eac
h group to h
a
v
e a ded
i
ca
t
ed a
qu
a
rium to r
ed
u
ce
c
ont
a
min
a
tion risks
.
T
o
a
voi
d
f
a
ilur
e
s
,
it is
c
ru
c
i
a
l to us
e
st
e
ril
e
t
ec
hniqu
e
s
a
n
d
thoroughly un
de
rst
a
n
d eac
h tr
ea
tm
e
nt pro
ce
ss to
e
nsur
e acc
ur
ac
y
a
n
d ac
hi
e
v
e de
sir
ed
r
e
sults
.
3
