Nichol and Acuna: Annual and batch fecundity of Limonda aspera in the eastern Bering Sea 
119 
Figure 9 
Comparison of predicted values of total fecundity as a function of fish length 
for yellowfin sole (Limanda aspera ), as presented by various authors. Error bars 
presented for the present study indicate 95% confidence intervals for the mean. 
the west coast of Kamchatka for five dif- 
ferent years, 1963—69. Because methods 
(i.e. selection criteria for ovaries) likely 
varied among studies, critical interpre- 
tation of these comparisons is difficult. 
Comparison of yellowfin sole with 
other species 
Yellowfin sole is more fecund and spawns 
smaller eggs than other flatfish species 
in the eastern Bering Sea (Table 7). Most 
flatfishes in the eastern Bering Sea, with 
the exception of northern rock sole ( Lep - 
idopsetta polyxystra, Orr and Matarese, 
2000), spawn pelagic eggs intermittently 
(in batches). Longhead dabs, also within 
the genus Limanda ( proboscidea ), have 
similar reproductive characteristics to yel- 
lowfin sole in respect to their high fecun- 
dity at length, small diameter of eggs, 
shallow spawning location, and spring- 
summer spawning season (Table 7). 
Yellowfin sole are most closely related 
to yellowtail flounder, Limanda ferrun- 
ginea (Cooper and Chapleau, 1998), a 
western Atlantic species ranging from 
the Gulf of St. Lawrence to Chesapeake 
Bay (Howell, 1983; Zamarro, 1992). Al- 
though only morphological characters 
were used to determine the phylogenetic 
relationships of these two species among 
pleuronectids (Cooper and Chapleau, 1998), yellowfin sole 
and yellowtail flounder also share very similar life history 
characteristics. Fecundity ranges, egg diameter, egg type, 
spawning interval, and spawning seasons are very simi- 
lar between the two species (Table 7). Like yellowfin sole 
females, yellowtail flounder females develop oocytes in a 
group-synchronous manner (Howell, 1983). In addition, 
they have MN oocytes present in their ovaries that con- 
tain hydrated oocytes, indicating that spawning of batches 
is similarly continuous (Zamarro, 1992). Yellowtail floun- 
der spawn approximately 7 batches compared with 8-11 
for yellowfin sole in the eastern Bering Sea. In short, close- 
ly related species share more than just morphological sim- 
ilarities; reproductive characteristics also reflect a shared 
evolutionary history. 
Spawning habits 
Yellowfin sole in the eastern Bering Sea have been ob- 
served from prespawning to spawning conditions from 
mid-May through August (Fadeev, 1970; Nichol, 1995). 
Observations of eggs and early-stage larvae in ichthyo- 
plankton surveys conducted in the eastern Bering Sea 
(Musienko, 1963; Waldron, 1981) indicate that spawning 
may not completely end until September. Given that the 
spawning season is protracted and that spawning of a 
series of batches is fairly rapid, individuals may have the 
potential to recover spent ovaries and spawn more than 
one series of batches within a single year. The possibility 
that residual chorion tissue is left over from the previous 
year’s spawning seems unlikely given that it would have 
been retained within the ovary for more than 8 months 
(Sep-May). 
Yellowfin sole remain in the spawning area ( <30 m bot- 
tom depth) until a series of batches have been spawned. 
The absence of partially spawned fish, those with ovaries 
containing POFs and AY oocytes, found outside the spawn- 
ing area ( >30 m) indicate that after spawning begins 
(first batch) fish remain in the spawning area until spent. 
Again, the presence of MN oocytes in most ovaries under- 
going oocyte hydration indicates that there is very little 
lag period between batch spawnings. This evidence refutes 
an earlier assertion by Nichol (1995) that yellowfin sole 
may migrate in and out of the spawning area between 
batch spawnings. However, some females do migrate out 
of the spawning area after a series of batches has been 
completely spawned; both spent and maturing (maturity- 
code 2) females with evidence of completed batch spawn- 
ings (i.e. with residual chorion tissue) were observed in 
spawning ( <30 m) and nonspawning ( >30 m) waters. 
Acknowledgments 
Claire Armistead, Jan Haaga, Mark Conrad, and Gary 
Walters aided with tissue collections. Frank Morado, Lisa 
