WYLLIE ECHEVERRIA: REPRODUCTION OF CALIFORNIA ROCKFISHES 



2) has spermatogonia! cysts developing throughout 

 the testis. There is no sign of spermatozoa in the 

 sperm duct. Externally, the testes appear slightly 

 swollen and white; in cross section they are translu- 

 cent in the center because of the absence of sperm 

 in the sperm duct. 



In a maturing male (Gonad Stage 3) spermatozoa 

 appear throughout the testis in spermatozoan cysts. 

 The sperm duct often contains remnants of residual 

 sperm from the previous reproductive season. In a 

 cross section the testis is swollen and whitish at the 

 periphery and brownish off-white in the center 

 because of the presence of residual sperm in the 

 sperm duct. 



As the reproductive season approaches (Gonad 

 Stage 4) the spermatozoan cysts burst open, re- 

 leasing spermatozoa into the efferent ducts and the 

 sperm duct. Externally the testis is large, soft, and 

 very white, sperm flows freely when the testis is 

 pressed or cut. During the reproductive season sper- 

 matogenesis has ceased and the spermatozoa have 

 moved from the periphery towards the sperm duct 

 so that the periphery becomes hard and discolored. 

 The central area may be swollen with sperm. 



At the end of the reproductive season (Gonad 

 Stage 7), the testis undergoes resorption and re- 

 organization, wherein smooth muscle cells, connec- 

 tive tissue, and scattered residual spermatozoa, con- 

 stituting cellular detritus, are evident in the histo- 

 logical sections. At the periphery, a new generation 

 of germ cells reorganizes along the spermatogen- 

 ic tubules. Externally the testis is a compact, ir- 

 regular triangular shape that appears gray or 

 brown. 



An understanding of the developmental sequence 

 on the cellular level aids in the interpretation of 

 gonad stage in the field. The four, difficult to inter- 

 pret, transitional stages can be clarified: 1) The first 

 reproductive year is indicated by a white periphery 

 (sperm) and an absence of sperm in the center of 

 a cross section of testis, a thin ovarian wall and no 

 residual pigmented eyes in ovaries. 2) The center 

 of the prespawned testis is firm and a dark cream 

 color (residual sperm); the periphery is white and 

 swollen with sperm. The postspawned testis usual- 

 ly shows signs of white fluid (sperm) in the sperm 

 duct and is firm and a dark cream color at the peri- 

 phery. 3) Unfertilized eggs are opaque yellow or 

 white held tightly in grapelike clusters while fer- 

 tilized eggs are a translucent yellow or white and 

 the outer eggs can be separated from each other. 

 4) Vitellogenesis is indicated by a deep yellow color 

 and swelling of the eggs so that the ovarian wall fits 

 tightly around the eggs; spermatogenesis is in- 



dicated by a softening and swelling of the testis and 

 a whitening at the periphery. 



Reproductive Maturity 

 and Seasonality 



Maturity was observed over a broad age and size 

 range within species throughout the years sampled. 

 The age and size at first maturity, 50% maturity and 

 100% maturity were estimated for males and 

 females of each species (Table 4). Males reached 50% 

 maturity either at the same or younger age than 

 females. Size at 50% maturity is generally similar 

 or somewhat smaller for males than for females of 

 the same species. The standard linear regressions 

 were run on the transformed logistic for the seven 

 principal species occurring in this study, resulting 

 in similar estimates of age at 50% maturity for S. 

 entomelas, S. flavidus, S. goodei, S. melanops, S. 

 mystinus, S. paucispinis, and 5. pinniger (Table 5), 

 and similar, if not exact, sizes at 50% maturity as 

 estimates derived from the raw data. Maturity for 

 species without sufficient data for statistical treat- 

 ment are estimated from the raw data. 



The reproductive season in Sebastes can be long 

 with larval extrusion (parturition) seen in females 

 of some species for up to 9 months (Table 6). From 

 all the data collected between 1977 and 1984 a sum- 

 mary of principal month of spermatogenesis, fer- 

 tilization, and parturition was determined for 32 

 species (Table 7). A span of 1 to 5 months between 

 peak spermatogenesis and fertilization is seen. The 

 time, when males ripen and mate, is not dependent 

 upon the eggs being fully mature. The time between 

 fertilization and parturition is usually about 1 month 

 (Moser 1967a). 



Reproductive seasonality for the principal species 

 sampled is displayed graphically in Figures 1-7. 

 Seasonality histograms are available, upon request, 

 for most species investigated. The general trend in 

 the seasonality oi Sebastes is a prolonged reproduc- 

 tive period for each maturity stage. This trend is 

 seen in the seven most abundant species sampled 

 (Figs. 1-7). Spermatogenesis (Gonad Stage 3) occurs 

 over 3 to 5 months before the testes are fully ripe 

 (Gonad Stage 4). The timing of mating is estimated 

 from the appearance of testes swollen with sperm. 

 At least part of the male population is ready for 

 mating for a period of 2 to 4 months. In females, 

 generally, fertilized eggs (Gonad Stage 4) are found 

 1 to 3 months after mating. Eyed larvae (Gonad 

 Stage 5) appear from 1 to 4 months after fertilized 

 eggs were observed and were present in the sam- 

 pled population for 3 to 6 months, usually with a 



241 



