ROSS and MERRINER: REPRODUCTIVE BIOLOGY OF BLUELINE TILEFISH 



Table 5. — Frequency of male and female 

 Caulolatilus microps from North and South 

 Carolina within age groups with Chi-square 

 values assuming 1:1 sex ratio. 



*P<0.05. 



the sex ratio was essentially 1:1. In fish > 600 mm TL, 

 males became increasingly and significantly more 

 abundant. Similarly, females outnumbered males in 

 ages III through VII while males became pre- 

 dominant for ages X through XV. 



Histological evidence from four juvenile blueline 

 tilefish indicated prematurational sex reversal. The 

 gonad from a 186 mm TL specimen was ovarian and 

 composed of basophilic oogonia with some primary 



oocytes (Fig. 11). The remaining three specimens 

 had gonads which exhibited progressive stages of sex 

 reversal. The earliest stage (202 mm TL) was pre- 

 dominantly ovarian with an acidophilic germinal tes- 

 ticular mesothelium proliferating through the 

 ovigerous lamellae from the dorsomedial connective 

 tissue (Fig. 12). The proliferating mesothelium con- 

 tained primary spermatogonia and would be the site 

 of steroidogenesis, inducing atresia and the recycling 

 of ovarian elements (Hoar 1969). Gonads of two 

 specimens (178 and 184 mm TL) in advanced stages 

 of sex reversal had differentiated into the basic tes- 

 ticular components with spermatogenic tubules pres- 

 ent and spermatogenesis proceding (Figs. 13, 14). 

 Both specimens revealed evidence of a previous 

 ovarian stage in the form of atretic structures, 

 residual oocytes, or proliferating testicular meso- 

 thelium along the peripheral epithelium. These 

 specimens were all captured in March and were 

 within the size range predicted for C. microps after 

 one year of growth (Ross and Huntsman 1982). 

 Residual oocytes were also observed in 8 of 41 

 developing testes from adult males (Fig. 15). These 

 fish were 430-700 mm TL and had solid testes 

 which exhibited no other remnant ovarian struc- 

 tures. 





^ 



"•***, 

 »••. 





FIGURE 11. — Cross section of ovary from a juvenile 186 mm TL Caulolatilus microps collected 13 March 1961 with 

 oogonia and primary oocytes (I) (Haematoxylin and eosin X 200). 



563 



