Nichol and Acuna: Annual and batch fecundity of Limanda aspero in the eastern Bering Sea 
113 
Table 3 
Two-way analysis of variance results comparing differences of oocyte density (top), and mean oocyte diameter (bottom) between 
blind and eyed-side ovaries and among anterior, middle, and posterior tissue subsampling positions in yellowfm sole, Limanda 
aspera. Paired r-tests ( H 0= d post -d ant ', H 0 =d pnsl -d mid ) among ovary positions indicate significantly (P<0.05) greater oocyte densities 
(d) in posterior tissue samples compared with either anterior or middle positions. SS = sum of squares; MSE = mean square error. 
Source 
df 
SS 
MSE 
F 
P-value 
Oocyte density (no. oocytes/g ovary tissue) 
Fish 
19 
3,391,989,272 
178,525,751 
62.32 
0.0001 
Ovary 
1 
3,466,212 
3,466,212 
1.21 
0.2708 
Position 
2 
25,951,981 
12,951,981 
4.53 
0.0125 
Ovary x position 
2 
9,505,128 
4,752,564 
1.68 
0.1914 
Error 
95 
268,371,656 
2,824,965 
Corrected total 
119 
3,699,284,249 
Mean oocyte diameter 
Fish 
19 
5.7136 
0.3007 
183.25 
0.0001 
Ovary 
1 
0.0003 
0.0003 
0.19 
0.6655 
Position 
2 
0.0034 
0.0017 
1.02 
0.3600 
Ovary x position 
2 
0.0022 
0.0011 
0.68 
0.5044 
Error 
5975 
9.8053 
0.0016 
Corrected total 
5999 7 
15.5248 
1 n = 6000; 2-ovary x 3-ovary positions x 20-fish x 50-oocytes/fish. 
another standing stock of oocytes for spawning within the 
same reproductive season. 
Homegeneity of oocytes between and within 
ovaries 
Two-way ANOVA on mean oocyte diameters indicated that 
the means were not significantly different between ova- 
ries or among the anterior, middle, and posterior ovary 
positions (Table 3). Additionally, our analysis revealed 
that oocytes were slightly more concentrated (number of 
oocytes/g ovary tissue) in posterior tissue samples com- 
pared with middle and anterior samples (paired £-tests, 
H o- d po S t-^ant=Q and H o- d post-^nud= 0 ’ n = 20 > ^-values <0.05; 
Table 3 ). Comparison of oocyte density between middle and 
anterior tissue samples and between eyed-side and blind- 
side ovary lobes revealed no significant differences ( paired 
£-test; P-value >0.05; Table 3). These results prompted us 
to take fecundity subsamples from two ovary locations 
(posterior and middle-anterior position from either ovary 
lobe) and to incorporate weighting factors (WF\ Eq. 2) for 
all calculations of total fecundity. 
The evidence for greater posterior-end oocyte densities 
that was found in 20 test fish prior to fecundity subsam- 
pling, was also present after all ovaries were subsam- 
pled. Oocyte densities were significantly greater in the 
posterior ovary end versus the anterior-middle positions 
among all ovaries sampled for fecundity (paired t-test, 
H 0 : d post -d ant / mid = 0; £=2.59; n= 323; P=0.0100). The densi- 
ty of hydrated (HY) oocytes within maturity-code-3 ova- 
ries, used for batch fecundity estimates, was also greater 
in subsamples taken from the posterior ovary end (paired 
'-test, H 0 . d post -d ant/mid = 0; £=3.40; n= 75; P=0.0011). Com- 
putation of batch fecundity, therefore, incorporated the 
same weighting factors described for computation of total 
fecundity. 
Oocyte size distributions 
Oocyte diameter plots indicated a hiatus in distribution 
between AY oocytes and PY oocytes for ovaries with mean 
AY diameters >0.38 mm (Fig. 3). This separation of AY 
oocytes from other oocyte stages in more advanced ovaries 
(closer to spawning) is indicative of a determinate mode 
of oocyte development. In prespawning fish (maturity-code 
2, no POFs), oocyte size distributions overlapped for fish 
with mean AY diameters less than 0.38 mm. PY oocytes, 
however, were a relatively minor portion in terms of oocyte 
density of the overall distribution for ovaries with mean 
AY diameters greater than 0.38 mm (Fig. 3). Oocyte distri- 
butions in maturing (maturity-code 2) fish with residual 
chorion tissue present in the ovary lumen exhibited the 
same hiatus between PY and AY oocytes where mean AY 
diameters were >0.38 mm (Fig. 3). 
The size distribution of AY oocytes for those fish that 
were either spawning their first batch (maturity-code 4, no 
POFs; n = 13) or had begun spawning (maturity-code 2 or 
3, POFs present; n= 23) was separated from PY and non- 
yolked oocyte distributions in 33 of the 36 fish examined. 
PY oocytes were either absent or were a very small frac- 
tion of the number of AY oocytes present. From the histo- 
logical analysis, we found that 68 of the 86 fish that had 
begun spawning (maturity-codes 2 and 3 with POFs, and 
maturity-code 4) did not contain any PY oocytes, further 
indicating that only one stock of oocytes is advanced prior 
to the spent ovary condition. 
