Yoneda et al.: Reproductive cycle, fecundity, and seasonal distributions of Lophius litulon 
367 
This difference in spawning season depending on latitude 
would indicate that the spawning season of L. litulon in 
Japanese waters occurs progressively later, with increas- 
ing latitude. This also occurs with L. americanus (Bigelow 
and Schroeder, 1953) in American waters and with L. pis- 
catorius (Afonso-Dias and Hislop, 1996) in northern Euro- 
pean waters. 
After spawning, ovaries in two conditions (stages 4 and 
5) were observed during our study. Females had postovula- 
tory follicles and yolked oocytes at the primary or second- 
ary yolk oocyte stages. Secondary yolk stage oocytes were 
more often present in the ovaries of females collected in the 
Table 6 
Gonadosomatic index ( GSI, mean ± SE ) and hepatosomatic 
index (HSI, mean ± SE) at each stage of maturity for male 
and female Lophius litulon. Values with different super- 
scripts are significantly different (Dunn’s multiple com- 
parison test, P<0.05). See tables 5 and 6 for definitions of 
maturity stages. 
Maturity stage 
of the gonads 
n 
GSI 
HSI 
Male 
1 
47 
1.17 ±0.25" 
5.57 ±0.77 
2 
143 
2.00 ±0.22" 
4.70 ±0.44 
3 
63 
2.09 ±0.10" 
4.80 ±0.37 
4 
114 
2.48 ±0.07'’ 
4.50 ±0.24 
Female 
1 
206 
1.34 ±0.08" 
5.40 ±0.25" 
2 (early) 
24 
5.73 ±0.42'’ 
10.38 ±0.70'' 
2 (late) 
10 
15.27 ±2.02'’ 
11.21 ±1.30'’ 
3 
4 
51.78 ±5.49'’ 
3.58 ±0.23" 
4 
7 
7.07 ±0.39'' 
6.03 ±0.84"' 
5 
11 
6.58 ±0.61'’ 
4.34 ±0.53" 
6 
5 
2.85 ±0.37" 
6.37 ±0.94"' 
first half of the spawning period ( February-March ). It seems 
likely that these normally develop into yolked oocytes 
because no signs of oocyte atresia were observed in histo- 
logical examination. Specimens with primary yolk oocytes 
were collected between March and May. However, there 
was evidence of atresia in half of the fish collected during 
the latter half of the spawning period (April-May). 
