1 20° E 125°E 130°E 120°E 125°E 130°E 120°E 125°E 130°E 
368 
Fishery Bulletin 99(2) 
A solitary female L. litulon, in Oarai Aquarium, released 
an infertile egg mass on 19 April 1994 and 35 days later 
extruded another mass. 2 Similarly, another captive female 
spawned three times, on 15 February, 2 June, and 21 July 
<D P 
£ ^ 
C/3 -rH 
p > 
c ^ 
■5 .s 
S 0J 
a h 
m 5 
" 2 
p h 
CD ^ 
cd 
6 fe 
P ~Q 
c g 
i> 5 
LO P 
2 g O 
P c o 
° 0 O 
S* n a; 
c ~ II M 
c s ® s 
£ a 13 to 
c « £ ^ 
a -d T '3 
(D ^ -m ^ 
■t— i O • ^ 
4-h c/3 5-< - 
-rt ^ 9 
1998. These data indicate that L. litulon may have the po- 
tential to spawn more than once a year, although the five 
spawnings observed in the aquarium were not accompanied 
by normal spawning behavior. Recently, we reported a case 
of repeated spawning in L. setigerus, which 
has a long spawning period from May to No- 
vember (Yoneda et al., 1998a). In contrast, L. 
americanus (Feinberg, 1984) and L. piscato- 
lius (Afonso-Dias and Hislop, 1996) are be- 
lieved to spawn only once a season. Future 
field studies are required to determine the 
spawning frequency for L. litulon , which will 
be important for estimating its reproductive 
potential. 
Both sexes of L. americanus inhabiting 
northern waters were larger and a little 
younger at 50% sexual maturity than fish 
from more southern waters (Almeida et 
ah, 1995). In L. litulon, there also appears 
to be a size difference at sexual maturity 
between fish from the East China and Yel- 
low seas (our study) and those from Sendai 
Bay off northeast Honshu Island (Kosaka, 
1966); the minimum size at sexual matu- 
rity for males and females was 340 mm 
body length (BL) and 600 mm BL for Ko- 
saka’s report and 325 mm TL and 546 mm 
TL for our results, respectively. The study 
from Sendai Bay, however, was carried out 
about 30 years ago and did not identify the 
age at sexual maturity; therefore the dif- 
ferences by area for size at sexual maturi- 
ty may be attributed to different sampling 
times of the year or to different growth 
rates. In the East China and Yellow seas, 
females L. litulon reached sexual maturity 
at larger than 500 mm BL, and the min- 
imum size at sexual maturity was about 
350 mm BL in male, as previously report- 
ed by Yamada (1986). The size at sexual 
maturity for female L. litulon in the 1980s 
(Yamada, 1986) is fairly close to our re- 
sults, whereas that for males is higher 
than that found in our study. Although 
the reason for the size difference found in 
males at sexual maturity is unclear, it may 
be due to a difference in criteria for ma- 
turity. Our histological criteria for maturi- 
ty in males were based on the characteris- 
tics of testicular development with unique 
spermatogenesis; therefore our determina- 
tion of sexual maturity is more reliable 
than macroscopic methods. 
There was a noticeable inverse correla- 
tion between the development of the ovary 
and the weight of the liver (HSI). The de- 
03 
J J TL 
i; p f 
03 C CD 
•a 5 % 
d CD -2 
P C/3 03 
P q 1 
_ CD 
8 O £ 
0) lO 
« c 1 
^ (D D 
<D N ^ 
'E. '55 133 
D- n, O 
,h 3^ -U 
_ < 
C/3 d 
C/3 g 
(D P 
03 
. s 
3 
03 
s 
p 
p 
03 
03 
o3 
o 2 
03 P H-N 
p x 7 
o D i 
O C/3 QJ 
j; ^ P 
O 03 g 
| £ o 
« s ^ 
• p o- d 
o p 
p, ^ 03 
C> w ^ 
'h 3 P 
® -e g 
a > -2 
Pc 1 ' 
.5 -S m 
Sac 
« 5 
S d 
£ £ 
O 
>> w 
03 C/3 
P cc 
X m 
03 l; 
C/3 ^ 
C/3 d 
03 ^ 
P 
d cp 
I 
>> 
p 
p 
03 
P 
rC 
bb d) 
§ | 
° P 
9" S oi cp 
£ S d ^ 
Sq ■p 03 ° 
g § S3 
O 32 £ H 
LO 
CO 
O 
CO 
2 Kofuji, K. 1998. Personal commun. Oarai 
Aquarium, Isohama, Oarai, Higashi-Ibaraki, 
Ibaraki 311-1301, Japan. 
