ROSS and MERRINER: REPRODUCTIVE BIOLOGY OF BLUELINE TILEFISH 



r''*& *«%'• •>*; SGI j 







FIGURE 3.— Cross section of Developing testes from a 664 mm TL Caulolatilius microps captured 9 September 1974. Note 

 spermatogenic tubules composed of the spectrum of developing crypt stages, with primary (SGI) spermatogonia; 

 primary (SCI) and secondary (SC2) spermatocytes; spermatids (ST); and collections of spermatozoa (SP) in the lumen 

 (Haematoxylin and eosin X 200). 



packed sinuses of spermatozoa, the spermatogenic 

 tubules of ('. microps maintain their integrity. 

 Drainage of spermatozoa from the testes results from 

 the dynamic nature of the tubules. In the course of 

 their development, they migrate medially from the 

 lateral epithelium. Several observations support this 

 hypothesis. In an early-developing male captured in 

 May (Fig. 4), the lateral spermatogenic tubules are 

 undeveloped and inactive with small amounts of 

 spermatozoa in the lumen. Those adjacent to the dor- 

 somedial portions of the testes are also generally 

 inactive but contain larger collections of sper- 

 matozoa. This suggests that longevity of sper- 

 matogenic tubules exceeds one season and that 

 spermatogenic tubules generate from the peripheral 

 interstitium (Lofts 1968). The spermatogenic tu- 

 bules adjacent to the dorsomedial connective tissue 

 in developing testes are generally the most well 

 developed, and can be seen merging with the medial 

 collecting tubules (Fig. 5). The collecting tubules 

 have boundary cells that are essentially connective 

 tissue, and contain only spermatozoa. The sper- 

 matogenic tubules can be distinguished, since they 

 are bordered by active spermatogenic crypts. Tes- 

 ticular drainage is thus accomplished by a dor- 



somedial migration of spermatogenic tubules and 

 their merging with and releasing of spermatozoa into 

 the collecting tubules. The collecting tubules chan- 

 nel the spermatozoa posteriorly and ventrally into 

 the separate sperm ducts. 



Spawning Seasonality 



Caulolatilus microps spawn off North Carolina and 

 South Carolina between April-May and September- 

 October. Monthly mean GSI values for 138 females 

 and 101 males captured off North Carolina exhibited 

 peaks in May and September (Fig. 6). Early- 

 Developing ovaries were predominant from Feb- 

 ruary through April. High GSI values in May 

 corresponded to the greatest incidence of Well- 

 Developed and Ripe females (Fig. 7). The lower 

 mean GSI values observed in June, July, and August 

 corresponded with a diversity of gonad stages includ- 

 ing Early-Developing, Well-Developed, Ripe, and 

 Recently Spent-Redeveloping ovaries. Ovaries were 

 again synchronously Well-Developed or Ripe in Sep- 

 tember though considerably smaller than gonads ob- 

 served in May and June. Low GSI values from 

 November through March reflect a period of gonad 



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