Hunter et al . Fecundity, spawning, and maturity of Microstomus paaficus 



107 



Figure 2 



Three stages of preserved whole 

 yolked oocytes of Dover sole Micro- 

 stOTTMS pacificus (stages defined in 

 text). Lower panel also shows migra- 

 tory nucleus (MN) oocytes, a hydrated 

 (H) oocyte, and an o-atretic advanced 

 yolked oocyte (A). The small air bubble 

 on the hydrated oocyte is an artifact. 



Batch fecundity 



Batch fecundity was considered to be the number of 

 migratory nucleus-stage oocytes or number of hydrated 

 oocytes in the ovary. We used the gravimetric method 

 to estimate numbers of these oocytes. Migratory 

 nucleus-stage and hydrated oocytes stand out as 

 discrete and easily identified oocyte maturity-classes 

 (Fig. 2). Hydrated ovaries that contained new post- 

 ovulatory follicles were not used to estimate batch 

 fecundity. 



We assigned each spawning batch to one of a pos- 

 sible five batch-order designations [1, 2, (2<B<U-1), 

 (U- 1), and U], where B is the batch-order number and 

 U is the total number of spawning batches. The five 

 batch-order designations were defined as follows: first 

 batch (where B = l), nonhydrated, advanced yolked 

 oocytes present and postovulatory follicles absent; sec- 

 ond batch (where B = 2), one class of postovulatory 



follicles and nonhydrated, advanced yolked oocytes 

 present; intermediate batches (where B>2 but less 

 than U- 1), two classes of postovulatory follicles and 

 nonhydrated, advanced yolked oocytes present; the 

 penultimate batch (U - 1), only two batches were pres- 

 ent, one of hydrated and one of migratory nucleus 

 oocytes, with no other advanced yolked oocytes pres- 

 ent; and last batch (U), no advanced yolked oocytes 

 present other than a single hydrated batch. 



In this classification scheme, we assumed that (1) the 

 presence of a single class of postovulatory follicles in- 

 dicated one spawning had occurred; (2) the presence 

 of two classes indicated at least two spawnings had 

 occurred; and (3) the absence of postovulatory follicles 

 indicated no spawning had occurred. The assumption 

 of no spawning would not hold if the interval between 

 spawnings was sufficiently long for postovulatory 



