50 



Fishery Bulletin 98(1) 



Table 2 



Fork lengths and weights of stomach contents, intestinal contents, and livers of embryos from two litters that contained one unusually 

 small embrvo. 



Litter 1 



Litter 2 



Embryo fork lengths (cm) 

 Length range ( cm ) 

 Length range as percentage of mean length (%) 



Smallest embr\'o 



Stomach contents (kg) 

 Intestine contents (kg) 

 Liver (kg) 



Other three embryos 

 Stomach contents (kg) 

 Intestine contents (kg) 

 Liver (kg) 



All embryos were collected between 11 

 March and 16 July, reflecting the seasonality 

 of the longline fisheries. The mean length of 

 Southern Hemisphere embryos in a litter in- 

 creased significantly (P<0.01 ) with sampling 

 date (Fig. 7): 



Mean FL i cm) 



9.36 + 7.48 month, 



{«=39,r2=0.27) 



where "month" is defined as the number of 

 months elapsed since 1 January. There was 

 considerable unexplained variability. For ex- 

 ample, in April, mean embryo length varied 

 between 20.3 and 63.5 cm. Inspection of the 

 data by year of collection and sampling lo- 

 cation showed that the variability was not 

 caused by interannual or spatial differences. 

 A regression equation fitted to North Atlan- 

 tic embryo data (Fig. 7) was 



Mean FL (cm) 



23.51 + 6.78 month 



{n=29, 7-2=0.70) 



Diameter (mm) 



Figure 5 



Frequency distribution of ovarian ova diameters from a pregnant por- 

 beagle from Macquarie Island, n = sample size. 



The North Atlantic regression explained a much 

 higher proportion of the variation but displayed con- 

 siderable length variability in early gestation. A homo- 

 geneity of slopes test showed that the regression slopes 

 for the two hemispheres were not significantly differ- 

 ent (P=0.76). The pooled data had a regression slope 

 (=embryonic growth rate) of 7.1 cm per month, and the 

 regression intercepts differed significantly (analysis of 

 covariance, P=0.004) by 12.0 cm, which is equivalent to 

 a temporal displacement of about 1.7 months. 



Small, postnatal juveniles 58-68 cm long (72=53), 

 were obsei-ved on Australian longlines between 22 

 May and 9 September, with a mean capture date of 15 

 July. Large embryos (up to 67 cm) were observed be- 

 tween mid-April and mid-June (Fig. 7). In the South- 

 em Hemisphere, the large variation in embryo length 

 at any one time, and the long period over which small 

 juveniles, assumed to be newborn, were collected, in- 

 dicate that the parturition period is lengthy. Parturi- 

 tion probably peaks in June-July (winter) but may 



