Sex diereniiætiah and pubey
105
and
growth rates reached sexual maturity at a given time ; in some lakes they
showed very
slow
growth rates but became mature at 6 years, while in other la—
kes
in
the
some
climatic
zone,
very
slowly growing females reached maturity
at
9
years.
Bream reaches
sexual maturity at 3—4 years of age in Arakum reservoirs
(43° N lat.)
and
in
the
Aral
Sea
(44° N lat.)
and
at 8—9 years
in Mik—
kelshkoe Lake
(63°N lat.).
Carp
reach
sexual
maturity
at
3—4
years
in
Arakum
reservoirs,
at
4—5
years
in
the
Volga river delta (46°N lat.)
(Shihshabekov, 1968), at 3—4 years
in
Poland
(about
52°N
lat.),
at
1
year
(120 g) in Israel (32°N let.), at 1
year
(males)
and
2
years
(females)
in
the
Rhone
delta
(43.5N lat.)
(Crivelli,
1981) and at 3 months in the climatic conditions of Java (7°N lat.)
(Epler and
Bieniarz,
1979).
Carassius
auratus
gibelio
in
Slovakia
(49°N lat.) becomes mature at 4—5
years
;
in
the
heated
waters
of
Moldavia
(47°N
lat.)
it
become
mature
at
2
years.
Sexual maturation of grass carp
(Gorbach and Kryhtin, 1981) in the Amur
river
(53°N lat.) depends on three interconnected factors : river water volume,
water
temperature
and
feeding habits.
With
low
water
levels
and
high water
temperature,
the
fish
start
wintering in good conditions,
and
then
in
spring
they reach sexual maturity fast and easily (males : at 6+, females at 8+ years
of age). With high water levels and consequently lower temperatures, the fish
are
weaker
when
wintering begins.
Thus,
after
the
winter period, the start to
feed intensively and reach sexual maturity at 10 or 12 years of age. In heated
water
in
Poland
grass
carp reach sexual maturity at 5—6 years (author's obser—
vations).
This
is
also
true
of
silver
carp
which,
in periods of low water le—
vels,
reach
sexual
maturity at 4+ — 5+ years, the females being two years la—
ter than the
males
;
at high water levels, this is reached at 6—10 years.
0
VT
ears
C
[la
b
"
30
»6
ia:
Ë
,
j
Ï
?
2o
;
L
;
7“
4
!
Ÿ
7‘= Î5‘
?
53
;
:
:
; ;
; ;
.
r
-
;
;;
;;
;;
f
;;
,:
;;
;;
f
f—
r
’
r
;
,
;;
':
«f
'
,,
;
;
—,‘_
{
f
4
’A
‘-4‘î
…A
4
64
4
Fig—1. Puberty of some cyprinids in the same lake (52°N lat.) before (a) and
after (b) being heated by electristation. l— winter temp., II— summer temp.
All
these
data
lead
to
the
fact
that
the
warmer
the
water,
the
earlier
Cyprinids reach maturity.
The
age
at
which
these
fish
living in a water body
under natural conditions
(in respect to age and season) reach maturity depends
on
the
latitude
;
the
more
south
a
water
body in the northern hem1sphere 1s
Situated, the earlier the fish mature.
105
and
growth rates reached sexual maturity at a given time ; in some lakes they
showed very
slow
growth rates but became mature at 6 years, while in other la—
kes
in
the
some
climatic
zone,
very
slowly growing females reached maturity
at
9
years.
Bream reaches
sexual maturity at 3—4 years of age in Arakum reservoirs
(43° N lat.)
and
in
the
Aral
Sea
(44° N lat.)
and
at 8—9 years
in Mik—
kelshkoe Lake
(63°N lat.).
Carp
reach
sexual
maturity
at
3—4
years
in
Arakum
reservoirs,
at
4—5
years
in
the
Volga river delta (46°N lat.)
(Shihshabekov, 1968), at 3—4 years
in
Poland
(about
52°N
lat.),
at
1
year
(120 g) in Israel (32°N let.), at 1
year
(males)
and
2
years
(females)
in
the
Rhone
delta
(43.5N lat.)
(Crivelli,
1981) and at 3 months in the climatic conditions of Java (7°N lat.)
(Epler and
Bieniarz,
1979).
Carassius
auratus
gibelio
in
Slovakia
(49°N lat.) becomes mature at 4—5
years
;
in
the
heated
waters
of
Moldavia
(47°N
lat.)
it
become
mature
at
2
years.
Sexual maturation of grass carp
(Gorbach and Kryhtin, 1981) in the Amur
river
(53°N lat.) depends on three interconnected factors : river water volume,
water
temperature
and
feeding habits.
With
low
water
levels
and
high water
temperature,
the
fish
start
wintering in good conditions,
and
then
in
spring
they reach sexual maturity fast and easily (males : at 6+, females at 8+ years
of age). With high water levels and consequently lower temperatures, the fish
are
weaker
when
wintering begins.
Thus,
after
the
winter period, the start to
feed intensively and reach sexual maturity at 10 or 12 years of age. In heated
water
in
Poland
grass
carp reach sexual maturity at 5—6 years (author's obser—
vations).
This
is
also
true
of
silver
carp
which,
in periods of low water le—
vels,
reach
sexual
maturity at 4+ — 5+ years, the females being two years la—
ter than the
males
;
at high water levels, this is reached at 6—10 years.
0
VT
ears
C
[la
b
"
30
»6
ia:
Ë
,
j
Ï
?
2o
;
L
;
7“
4
!
Ÿ
7‘= Î5‘
?
53
;
:
:
; ;
; ;
.
r
-
;
;;
;;
;;
f
;;
,:
;;
;;
f
f—
r
’
r
;
,
;;
':
«f
'
,,
;
;
—,‘_
{
f
4
’A
‘-4‘î
…A
4
64
4
Fig—1. Puberty of some cyprinids in the same lake (52°N lat.) before (a) and
after (b) being heated by electristation. l— winter temp., II— summer temp.
All
these
data
lead
to
the
fact
that
the
warmer
the
water,
the
earlier
Cyprinids reach maturity.
The
age
at
which
these
fish
living in a water body
under natural conditions
(in respect to age and season) reach maturity depends
on
the
latitude
;
the
more
south
a
water
body in the northern hem1sphere 1s
Situated, the earlier the fish mature.