Uchida (1959) for albacore. The measurement was 

 the random diameter located parallel to the ruled 

 lines marked on the measuring dish. 



For ovaries in the early ripe or ripe stages, ova 

 diameters were taken to obtain the mean diameter of 

 the most advanced mode. A small sample of the 

 ovarian tissue was extracted with a cork borer from 

 the area near the lumen of the posterior region of the 

 right ovary. Excess liquid was first blotted out and 

 the sample weighed on an analytical balance. All ova 

 in the most advanced stage were measured and 

 counted, the latter to obtain fecundity estimates. 



Weights of preserved ovaries from four fish were 

 not recorded (Table 1). Since three of these samples 

 were in the early ripe or ripe stages of maturity and 

 could be used for fecundity estimates, we computed 

 a conversion factor to correct for shrinkage due to 

 preservation. Figure 2 shows the regression of fresh 

 whole ovary weight on preserved (10% Formalin) 

 ovary weight. The regression computed on the trans- 

 formed data (log ^) shows a very good fit for the 12 

 sets of data. The equation was used to estimate the 

 preserved weights of the three samples (Table 1). 



Sample BB-3 (Table 1) was used to test for 

 homogeneity of ova diameters within a pair of 

 ovaries. A cork borer (14.29 mm diameter) was used 

 to obtain a core sample which extended from the 

 outer surface of the ovary to the centrally-located 

 lumen. The core was divided into an outer layer, a 

 central layer located next to the lumen, and a middle 



I 23456789 IP II 



LOGe FRESH WHOLE OVARY WEIGHT (gms) 



Figure 2. — Relationship of fresh ovary weight to pre- 

 served (10% Formalin) ovary weight for swordfish. 



layer. Separate cores were taken from the anterior, 

 middle, and posterior region of both ovaries, thus 

 providing a total of 18 subsamples. Ripe ova were 

 teased from each sample and 200 randomly-selected 

 ova were measured 



DEVELOPMENTAL STAGES OF OVA 



An examination of the physical appearance of ova 

 from swordfish showed that the ova could be clas- 

 sified easily into several developmental stages which 

 were not dependent on ova diameters. The stages 

 are described as follows: 



1 . Primordial Ova 



Ova are transparent, ovoid in shape, and diame- 

 ters range from 0.01 to 0.05 mm. Primordial ova 

 are present in all ovaries. 



2. Early Developing Ova 



Ova are still transparent and ovoid in shape; 

 diameters range from approximately 0.06 to 0.24 

 mm. A chorion membrane has developed around 

 the ovum and an opaque yolk-like material has 

 begun to be deposited within the ovum. 



3. Developing Ova (Figure 3A) 



Ova are completely opaque, more wedge-shaped 

 than ovoid, and diameters range between 0.16 to 

 0.96 mm. The chorion is stretched and not visible 

 in this stage. 



4. Advanced Developing Ova (Figure 3B) 



Ova are ovoid and diameters range from 0.47 to 

 1.20 mm. Ova have a translucent margin, a fertil- 

 ization membrane, and a round yolk. 



5. Early Ripe Ova (Figure 3C) 



Ova diameters range from 0.60 to 1.20 mm. The 

 yolk material is translucent and oil globules have 

 begun to form. 



6. Ripe Ova (Figure 3D) 



Ova are transparent and with oil globules. 

 Diameters range from 0.80 to 1.66 mm. 



7. Residual Ova 



Ova in this stage show signs of degeneration. Ova 

 are thin-walled and translucent and have shrunken 

 and measure approximately 0.80 mm in diameter. 



HETEROGENEITY 

 OF OVA DIAMETERS 



The distribution of ova diameters in sample BB-3 

 was examined critically to test for heterogeneity. A 

 chi-square test of the normality of the size frequency 

 distribution of ova diameters for the 18 samples (Ap- 

 pendix Table 1) showed significant differences for 



144 



