ROSS and MERRINER: REPRODUCTIVE BIOLOGY OF BLUELINE TILEFISH 



with 140-196 /x oil globule. Spermatogenic stages 

 were analogous to those described by Moe (1969) for 

 red grouper and Hyder (1969) for Tilapia. Routine 

 histological methods were used for slide pre- 

 parations from Formalin-fixed gonads. 



Frequency distributions of ova diameters were plot- 

 ted by gonad stage to determine individual spawning 

 patterns. Representative females were selected for 

 each ovarian stage. The diameter of 50 ova from each 

 occurring stage (previtellogenic, early vitellogenin 

 active vitellogenic, and mature oocytes) were 

 measured from each sample using a gridded petri 

 dish and a magnification of 70X. A ratio of the four 

 stages was then determined by reducing the magni- 

 fication to 20X and counting two or more entire 

 grids until about 500 ova were counted. This ratio 

 was reduced to a base of 200 and combined with ova 

 diameter frequencies per stage data using the ratio 



frequency of ova stage .. ova diameter frequency 

 200 50 



to determine the relative frequency of each size 

 group. 



Well-Developed and Ripe ovaries from fish cap- 

 tured from April through September were used for 

 fecundity estimates. One ovary randomly selected 

 from each pair was weighed to the nearest 0. 1 g. The 

 ova were teased free of the ovarian tunic. Two sub- 

 samples were removed and all vitellogenic ova 

 (stages III-V; determined by relative size and opacity 

 of cytoplasm) were counted. The sample and sub- 

 samples were oven dried and weighed to the nearest 

 0.001 g. The formula 



(W) ( W ) 



was used to estimate fecundity, with Y— total num- 

 ber of eggs in both ovaries, W — wet weight of both 

 ovaries, W, — wet weight of selected ovary, w ( = total 

 dry weight, w = total dry weight of subsamples, and y 

 = number of ova in subsamples (Manooch 1976). 



TABLE 1. — Developmental stages of Caulolatilus microps ovaries. 



Maturity stage 



External appearance 



Ova composition 



Immature 



(stage 1| (>250 mm TL) 



Resting 

 (stage 2) 

 Developing 

 (stage 3) 



Well- Developed 



(stage 4) 



Ripe 

 (stage 5) 



Recently Spent- 

 Redeveloping 

 (stage 6-3) 



Spent 

 (stage 6) 



Small, maroon, sausage to teardrop shaped hollow organs 



Flaccid triangular sacs with translucent tunic and dark redJish 

 internal mass 



Ovary becomes increasingly rotund while maintaining a basic 

 triangular shape, yellowish orange appearance due to granular 

 ovigerous mass tunic becomes more transparent, and ova are 

 discernable 



Ovarian tunic becomes nearly transparent yellowish ova densely 

 packed and discernable. 



May-August. Greatly distended, bulbous and occupying more 

 than 1/3 of the peritoneal cavity, very light orange to white in 

 color; 2-4% body weight. Ova clearly visible through delicate, 

 nearly transparent tunic. 



September-October: Ovaries comparatively smaller, firm, more 

 triangular though rotund; 1-2.4% body weight. 

 Resemble deflated early developing ovaries; distinguished by 

 inflamed ventral, posterior portion, otherwise cream colored. 



Flaccid, reduced in size; muscular tunic contracting and becom- 

 ing firm, inflamed 



Ovigerous lamellae composed of dense aggregations of undif- 

 ferentiated oogonia and primary oocytes. 



Primarily early and previtellogenic oocytes with <1 % early vitel- 

 logenic oocytes. 



Previtellogenic oocytes numerically dominant with some early 

 and active vitellogenic oocy*es. Well-developed ovaries contain 

 an increasing number of vitellogenic oocytes evenly distributed 

 over a large size range (21 5-650 u.). 



Vitellogenic oocytes predominant and evenly distributed over a 

 large size range (21 5-650 /i). 



Broad size distribution of vitellogenic oocytes, with a mode of 



very large (420-640 u.) vitellogenic oocytes together with stage 



III and small (21 5-400 u;) stage IV oocytes. Mature oocytes (785- 



910 u.) characteristically contained in lumen, free of ovigerous 



lamellae. 



A mode of large stage IV oocytes with stage V oocytes present 



and relatively few small (2 1 5-400 /i) stage IV oocytes. 



Stage III and small stage IV oocytes occur together with some 



very large stage IV and stage V oocytes, the latter often in an 



atretic state. 



No evidence of vitellogenesis; stage IV and V oocytes are atretic; 



a few stage III oocytes occur. 



TABLE 2. — Developmental stages of Caulolatilus microps testes. 



Maturity 

 stage 



External appearance 



Spermatogenic activity 



Immature/Resting 



Developing 



Well- 

 Developed 



Ripe 



Basically threadlike maroon organs with slight laterally com- 

 pressed expansion posteriorly above sperm duct. 



Maroon, thin, elongate, laterally compressed, with widest por- 

 tion directly above sperm ducts, tapering rapidly to filamentous 

 anterior projection. 



More robust, triangular to nearly cornucopia shaped, tapering 

 anteriorly. Maroon to creamy off-white color. 



Spermatogenic tubules generally inactive, though spermatozoa 

 may occur in lumen of spermatogenic tubules and collecting 

 tubules. 



Spermatogenic tubules contain crypts at all developmental 

 stages with spermatozoa collecting in the lumen and collect- 

 ing tubules. 



Extensive collections of spermatozoa in expanded lumens of 

 actively developing spermatogenic tubules, with channeling of 

 spermatozoa into medial collecting tubules. 



No running ripe testes observed 



555 



