FISHERY BULLETIN: VOL. 86, NO. 2 



flowing oocytes were only captured at dusk and 

 milt appeared to flow more freely in males at dusk 

 than at other times of the day. 



Gonadal Development in Males 



Testicular recrudescence began in January 

 with the appearance of primary spermatocytes 

 (Fig. 3), and by February the majority of the 

 males were in the early developing or developing 

 reproductive stage. In March, 89% of the males 

 had testes containing free spermatozoa (Fig. 3), 

 although only 27% were running ripe. Over 94% 

 of all males captured from April until the end of 

 August were running ripe. Spent males first ap- 

 peared in August and all the males during Octo- 

 ber and November were either in the spent or 

 regressed condition. In December, all males cap- 

 tured had regressed testes containing only pri- 

 mary and secondary spermatogonia (Fig. 3). 



Histological observations revealed that the 

 testes are the common unrestricted spermatogo- 

 nia type, as described by Grier (1981). Spermato- 

 genesis occurred throughout the entire testis dur- 

 ing the majority of the year. However, from late 

 February through early August, spermatogenesis 

 was more advanced in the central lobules then in 

 the peripheral lobules. By August there was no 

 spermatogenic activity in the central lobules, al- 

 though spermatogenesis continued in the periph- 

 eral lobules until mid-September. The only period 

 of the year when there was no active spermato- 

 genesis was from October through late January, 

 although primary and secondary spermatogonia 

 were present from October through the end of 



April (Fig. 3). Primary spermatocytes were com- 

 mon from late January until March, although 

 they did not disappear from the testes entirely 

 until the end of July. Secondary spermatocytes 

 first appeared in mid-February, were common 

 through the end of July and did not disappear 

 until early September (Fig. 3). Spermatids and 

 spermatozoa were present in the central lobules 

 by late February, and from March through mid- 

 August the central lobules were swollen with 

 spermatozoa (Fig. 3). In late August and Septem- 

 ber many of the central lobules appeared to be 

 partially empty of spermatozoa, although some 

 spermatozoa were still present up to mid-Novem- 

 ber (Fig. 3). The peripheral lobules contained ac- 

 tive spermatogenic cysts of primary and second- 

 ary spermatocytes during June and July and the 

 lumens of these lobules began to fill with sperma- 

 tozoa. The peripheral lobules were swollen with 

 spermatozoa during August and September, but 

 by mid-October no spermatozoa remained. 



Gonadal Development in Females 



Gonadal recrudescence was observed in a small 

 percentage of the females captured in January 

 and by March 94% of the females were undergo- 

 ing ovarian development (Table 3). Fish with ma- 

 ture ovaries were found from March until the end 

 of September, while running ripe fish were cap- 

 tured fi-om April through the end of September 

 (Table 3). Partially spent fish (females that ap- 

 peared to have spawned at least once but still 

 contained vitellogenic oocytes) were captured 

 from May through the end of September. No com- 



1° Spermatogonia 

 2° Spermatogonia 

 1° Spermatocytes 

 2° Spermatocytes 

 Spermatids 

 Spermatozoa 



A 



-| r 



J J 



Month 



M 



M 



A 



S 



— r 

 N 



D 



Figure 3. — Seasonal cycle of spermatogenesis in spotted seatrout collected in South Texas, as 

 determined by histological and macroscopic observations. Data from April 1982 through 

 mid-May 1985 are combined. 1° - primary, 2° - secondary. 



378 



