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Fishery Bulletin 94(2), 1996 



Table 1 (continued) 



Females (continued) 



Stage 



Macroscopic description 



Histological description 



Ooycte development 



8 Resting 



Aspect of ovaries as in previous 

 stage, not accurately distin- 

 guishable. 



Oocytes at stages 2 and 3 pre- 

 dominate, no trace of postovu- 

 latory follicles left, advanced 

 atresia of remaining yolked oo- 

 cytes, hydrated oocytes some- 

 times still present in lumen. 



Very small oocytes (stages 2 and 

 3) predominate, advanced atre- 

 sia of remaining yolked oocytes. 



Stage 



Males 



Macroscopic description 



1 Immature Testes very small, flat, and threadlike; 



2 Early developing Testes increase in size, rounder in shape; 



3 Developing Size of testes increases further, lobed in formation and marked groove in the middle of each testis 



visible, creamy or white milt sometimes present; 



4 Late developing Testes very large and multilobed. white or pinkish, sometimes bloodshot, free-flowing milt; 

 to running-ripe 



5 Spent and resting Testes much smaller, very bloodshot, milt sometimes present, become thinner, brownish and rubbery as 



they regress to resting stage. 



by using samples preserved in Davidson's solution. 

 Only early stages of atresia (stages alpha and beta 

 as described by Hunter and Macewicz, 1985b) were 

 considered (Fig. 3, B, C, and D); oocytes at later stages 

 of atresia are too difficult to identify with commonly 

 used histological techniques. 



Occurrence of postovulatory follicles The presence 

 of postovulatory follicles in ovaries was used to iden- 

 tify females that had begun to spawn. In addition, 

 examination of morphological changes in postovu- 

 latory follicles after ovulation ( as described by Hunter 

 and Macewicz, 1985b; Schaefer, 1987; Macewicz and 

 Hunter, 1993) provided information on spawning fre- 

 quency. Postovulatory follicles were classified into 

 two types according to the degree of resorption vis- 

 ible in histological sections. Type-1 postovulatory 

 follicles (Fig. 3A) were more recent, presenting an 

 involuted zona radiata with numerous folds and an 

 open cavity, as well as granulosa cells aligned within 

 the zona radiata; type-2 postovulatory follicles were 

 small, had fewer involutions, and showed a much more 

 reduced follicular cavity; at that stage the zona radiata 

 has thickened markedly and the granulosa cells are 

 disorganized. When present in ovaries, 50 postovulatory 

 follicles were randomly measured (along the perimeter) 

 with NIH image analysis software. 



Staging and measurement of whole oocytes Stag- 

 ing and measurement of whole oocytes was used to 

 assess whether the fecundity of blue-eye trevalla is 

 determinate or indeterminate, that is, whether yolk 

 formation is completed before spawning starts or 

 continues after (Hunter et al., 1985). This informa- 

 tion is needed to know whether the annual fecun- 

 dity of blue-eye trevalla can be estimated from a 

 standing stock of yolked oocytes (i.e. vitellogenic) 

 present in ovaries. Subsamples of ovaries preserved 

 in Davidson's solution were mixed in small jars with 

 water and 3-mm glass beads and shaken manually to 

 dissociate the oocytes. All ovaries used had been previ- 

 ously staged histologically, and histological sections 

 were used to stage corresponding whole oocytes under 

 a microscope (see description in Table 1 and Fig 3, C 

 and D, adapted from West, 1990; Hunter et al., 1992; 

 Davis and West, 1993). Fifty oocytes were measured 

 (along the maximum diameter) for 135 females at vari- 

 mis stages of maturity. Figure 3D also shows whole, 

 preserved postovulatory follicles of type 1 (type 2 were 

 too small to be properly dissected and photographed). 



Fecundity estimation Only ovaries that showed no 

 sign of previous spawnings (absence of postovulatory 

 follicles), no sign of major atresia, and in which oo- 

 cytes were fully yolked (as indicated by their diam- 



