HUNTER and MACEWICZ: ATRESIA IN NORTHERN ANCHOVY OVARY 



Table l. — Percentage of northern anchovy females with ovaries containing various levels of alpha stage atresia 



during starvation and after the resumption of feeding.' 



' Feeding begins on the 28th day. 



^N = mean number of atretic oocytes per 6 fim section. 



^F = mean percentage of atretic oocytes per 6 /um section. 



Table 2. — Percentage of northern anchovy females with ovaries containing various levels of beta and gamma+delta 

 stage atresia and yolked oocytes during starvation and after the resumption of feeding.' 



' Feeding begins on the 28th day. 



^N = mean number of atretic follicles per 6 /xm section. 



resorption (Fig. 4). None of the females sampled on 

 the 23d day had yolked oocytes, indicating that all 

 yolked oocytes had passed through the alpha stage 

 of atresia by this time. 



The resorption of unyolked and partially yolked 

 oocytes began just as rapidly as did the resorption 

 of yolked oocytes. The percentage of females with 

 atretic unyolked oocytes in the alpha stage in- 

 creased sharply from 21% on the 3d day of starva- 

 tion to 90% on the 13th day. Throughout the rest of 

 the 27-d starvation period nearly all of the females 

 (90-100% ) had some unyolked oocytes in the alpha 

 stage of atresia, indicating a continual recruit- 

 ment of atretic follicles from the unyolked and 

 partially yolked oocyte classes. Thus, alpha stage 

 unyolked and partially yolked oocytes are present 

 in regressing ovaries for a much longer period 

 than is the alpha stage of yolked oocytes. This 

 difference probably is due to the greater number of 



unyolked and partially yolked oocytes in mature 

 ovaries. Yolked oocytes constitute <1% of the total 

 number of oocytes present in mature ovaries. 



The incidence of beta stage atretic follicles also 

 increased sharply over the first 9 d of the starva- 

 tion period and followed a pattern similar to that 

 described for the incidence of alpha atresia from 

 unyolked eggs (Fig. 4). After attaining a high 

 value on the ninth day the incidence of beta 

 atresia remained high until the end of the starva- 

 tion period as atretic follicles from yolked and un- 

 yolked oocytes degraded from the alpha to the beta 

 stage of atresia. Incidence of gamma -I- delta stages 

 (the third and fourth stages of follicle degenera- 

 tion) increased later than did alpha and beta 

 stages and remained high after the onset of 

 feeding. 



Once feeding resumed (day 28), rapid resorption 

 of yolked and unyolked follicles ceased and the 



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