FISHERY BULLETIN: VOL. 85, NO. 2 



reproductive months and/or the principal month of 

 parturition. 



RESULTS 



Moser (1967b) described the seasonal changes in 

 gonads of mature S. paucispinis and should be con- 

 sulted for details of morphology. In this study a 

 general description of all maturity stages is included 

 with emphasis on the immature gonad and the tran- 

 sitional stages, which are difficult to interpret. The 

 transitional stages are 1) the determination of the 

 first reproductive year, particularly in species with 

 small maximum size; 2) the prespawned testis dur- 

 ing spermatogenesis compared with the spawning 

 and postspawned testis when spermatogenesis is 

 completed and mating is in progress or just com- 

 pleted; 3) the unfertilized egg stage compared with 

 the recently fertilized egg; and 4) the nonreproduc- 

 tive season, compared with the beginning of vitello- 

 genesis or spermatogenesis when the gonads are 

 beginning to mature. A comparison of external mor- 

 phology with the histological sections indicates that 

 the same sequence of spermatogenesis/vitellogene- 

 sis, mating, ovulation, fertilization, and larval ex- 

 trusion is followed for each species in this study. 

 There were not sufficient samples of all 31 species 

 to discern what developmental variations might 

 exist on the cellular level (Table 1). 



Developmental Sequence 

 of Ovaries 



The germ cells in ovaries are clustered in oogonial 

 nests, which are present throughout the year in 

 varying numbers. The ovary of an immature rock- 

 fish (Gonad Stage 1) consists primarily of oogonial 

 nests with oocytes <0.14 mm in diameter. The ovar- 

 ian wall is translucent and thin (approximately 0.1 

 mm thick). Externally the ovary appears translucent 

 with a tiny egg mass (Table 2). 



Approaching the first year of maturity (Gonad 

 Stage 2), the ovary is filled with oogonial nests, 

 follicles begin to form around maturing oocytes, and 

 the ovarian wall is translucent and thin. There is no 

 evidence of the resorption and reorganization seen 

 in spent ovaries. Externally the ovary appears pink 

 through the thin wall, and eggs about 0.2 mm in 

 diameter are visible. 



As the reproductive season approaches (Gonad 

 Stage 3) eggs are produced by the oogonial nests 

 and vitellogenesis begins, resulting in eggs enlarg- 

 ing from 0.2 to 0.5 mm in diameter. Follicles form 

 around the maturing eggs, a capillary network 

 develops throughout the ovary, and the ovarian wall 

 begins to thicken from 0.3 to 0.5 mm. Externally 

 the ovary appears either white or yellow and firm- 

 ly packed with eggs in grapelike clusters. The eggs 

 expand during this stage, so that during maturation 



Table 2.— Reproductive development at the cellular and external morphology level 

 for ovaries of Sebastes species. 



Gonad stage 



Cellular morphology 



External morphology 



1. Immature 



2. First year 

 maturity 



3. Vitellogenesis 



4. Fertilization 



5. Eyed larvae 

 (parturition) 



6. Spawned 



7. Resting 



Oogonial nests with oocytes 

 <0.14 mm. Ovarian wall (OW) 

 0.1 mm thick. 



Oocytes <0.2 mm. No evi- 

 dence of resorption. 



Mature oocytes 0.2-0.5 mm In 

 diameter within follicles. OW 

 0.3-0.4 mm thick. 



Oocytes 0.9 mm. Yolk globule 

 disintegration, ovulation, fer- 

 tilization. 



Larvae developed within chor- 

 ion with eyes pigmented black 

 or yellow. 



Oocytes 0.08-0.64 mm In 

 diameter. Resorption of blood 

 vessels, atretic oocytes, and 

 residual larvae. Collapsed 

 egg cases. OW 0.5-1.0 mm 

 thick. 



Resorption and reorganiza- 

 tion. Proliferation of oogonial 

 nests. OW 0.5-0.9 mm thick. 



Small and translucent to pink. 

 Ovarian wall (OW) thin. 



Pink with visible eggs. No 

 black pigmentation. OW thin. 



Yellow or white opaque eggs 

 In grapelike clusters. OW 

 thickening. 



Large clear eggs free In ovar- 

 ian cavity, but enveloped by a 

 network of capillaries. 



Large, soft, gray. Ovary breaks 

 easily, and is filled with eggs 

 and fluid. 



Flaccid, reddish-purple, or 

 grayish from residual larvae. 

 OW thick and tough. 



Firm, gray to pink. Tiny black 

 dots indicate residual larvae, 

 OW thick, tough, and loose 

 from eggs. 



232 



