Zimmermann: Maturity and fecundity of Atheresthes stomias 
609 
ogy that none of the “immature” females had begun 
acquiring yolk, some had begun the process of ma- 
turing oocytes, and several had atresia of large, pre- 
viously yolked oocytes, indicating that these females 
had probably spawned during the previous year. All 
females classified macroscopically as “developing” 
had maturing oocytes to spawn, most of them in the 
later stages of vitellogenesis. Few of the fish classi- 
fied as “spent or resting” were actually resting: most 
were in vitellogenesis and should have been classi- 
fied as “developing.” In addition, the author was un- 
able to assign a single maturity stage to ovaries with 
a mixed appearance and to assign a stage for ovaries 
from some females. 
The several females correctly classified as “spent 
or resting” deserve some discussion. These fish had 
oocytes only as advanced as the late perinucleus stage 
and had degenerating oocytes present, which had 
previously been yolked. These fish were classified as 
mature because they had previously contained yolked 
oocytes, but they were unable to spawn soon, despite 
the upcoming spawning season, and they did not 
show signs of recent spawning. Hunter and Macewicz 
(1985, a and b) have reported histological details on 
creation and resorption of atretic oocytes and 
postovulatory follicles in the northern anchovy, 
Engraulis mordax. Their results have shown that the 
relatively rapid resorption of yolked oocytes (after 
23 days of starvation; Hunter and Macewicz, 1985a) 
and postovulatory follicles (after 3-4 days; Hunter 
and Macewicz, 1985b) seems to contradict my asser- 
tion that atretic vitellogenic oocytes from the previ- 
ous spawning season were still being resorbed in 
arrowtooth flounder just prior to the spawning sea- 
son. A comparison of the reproductive cycle of 
arrowtooth flounder (which is a determinate-spawn- 
ing benthic flatfish, dwelling in relatively cold north- 
ern waters) with that of the northern anchovy (an 
indeterminate-spawning pelagic roundfish, occupy- 
ing much warmer southern waters) is not without 
merit. It is important to note, however, that signifi- 
cant differences could occur in the rate in which these 
species cycle between reproductive stages. Hunter 
and Macewicz (1985b, p. 87) caution that “the dura- 
tion of postovulatory stages must be newly estimated 
for each species, and an assumption that the dura- 
tion of these stages in a new species is similar to the 
northern anchovy is highly speculative.” Perhaps 
further sampling of this arrowtooth population closer 
to or during the spawning season could have pro- 
vided more information on the further development 
of these “spent or resting” fish. 
Macroscopic classification was not successfully 
applied to the males. Only by histologic work was male 
maturity confidently assessed. Rickey (1995, p. 130), 
in her nearly year-round sampling of arrowtooth 
flounder, also had difficulty with assigning macro- 
scopic maturity stages to males, stating that males 
“. . . did not show grossly apparent developmental 
changes over time ... no spawning males were seen.” 
In the present study, females were classified as 
mature if they had oocytes as advanced as the corti- 
cal alveoli stage (Rickey, 1995), or showed atresia of 
previously vitellogenic oocytes. Significant differ- 
ences in GSI and HSI occurred between the late 
perinucleus and cortical alveoli stages, and fish at 
the cortical alveoli stage were also longer and heavier. 
The insignificant but noticeable decline in condition 
factor in the cortical alveoli and early vitellogenic 
stages also indicates an emphasis in gonad growth 
over somatic growth. Rickey (1995), in examining 
Washington coast arrowtooth flounder collected dur- 
ing the spawning season, found that all of the fish 
had either matured beyond the cortical alveoli stage 
or had not yet matured that far. This finding sup- 
ports the idea that fish in the cortical alveoli stage 
prior to the spawning season will mature during the 
same spawning season. Histology is regarded as the 
best method available to assess maturity (Hunter et 
al., 1992; West, 1990), but Hunter et al. (1992) con- 
cluded that even with the broadest criteria defining 
maturity, some spent fish are not identifiable as post- 
spawners when sampling is done after spawning has 
commenced. 
Hosie and Barss 1 determined that Oregon arrow- 
tooth flounder males reach L 50 at 29 cm and females 
reach L 50 at 44 cm. Rickey (1995) determined that 
Washington males reach L 50 at 28.0 cm and females 
reach L 50 at 36.8 cm. Fargo et al. ( 1981) determined 
that British Columbia males reach L 50 at 31 cm and 
females reach L 50 at 37 cm. All the above studies 
determined maturity by using macroscopic classifi- 
cation of arrowtooth flounder gonads. 
It was thought that macroscopic observations of 
maturity would result in a lower L 50 , as all the other 
arrowtooth flounder maturity studies showed, but 
instead the L 50 based on macroscopic observations 
was 3 cm higher. This finding is the opposite of that 
found in a study by Walsh and Bowering (1981) who 
compared macroscopic and histological staging of 
Greenland halibut ( Reinhardtius hippoglossoides) 
ovaries and demonstrated that L 50 was 3 cm higher 
in the maturity ogive derived from histological work. 
Time of sampling in relation to the spawning sea- 
son may have been a factor in determining female 
L 50 . Hunter et al. (1992) showed that estimates of 
L 50 for female Dover sole (Microstomus pacificus ) 
taken during the spawning season were higher than 
estimates of L 5Q for female Dover sole taken just prior 
to the spawning season, whereas Rickey ( 1995) found 
