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Fishery Bulletin 97(4). 1999 



Litter size was found to be significantly correlated 

 with total length of the mother (P<0.01, r=0.52, n=38). 



The relation between shark length and liver mass 

 was very variable but approximated a power rela- 

 tion (Fig. 5). The maximum recorded weight of fe- 

 males was about three times that of males; varia- 

 tion was higher in mature and pregnant individuals 

 than in immature individuals. 



To investigate the possible function of the liver as 

 an energy source during pregnancy, female HSI was 

 plotted against mean embryo TL (Fig. 6). Although 

 the trend appeared negative, there was no signifi- 

 cant correlation between mean embryo length and 

 HSI (/ -0.242, P>0.05; n=31). 



Plotting mean embryo size against month of the 

 year resulted in a scatterplot with two clusters of 



points but with no clear trend (Fig. 7). Extending 

 the time axis to 24 months and shifting the larger 

 embryos 12 months along the time axis yielded a clear 

 trend. This finding would suggest that there is a ges- 

 tation period of 19-21 mo and that the entire cycle 

 spans approximately two years, excluding any rest- 

 ing period. Of a subsample of 11 mature females 

 taken between May and August, four (369^ ) were rest- 

 ing (they showed no sign of recent pregnancy and 

 had only small ova in the ovary) and the rest were 

 pregnant, five (46%) with pups of intermediate size 

 and two (18'^) with large, near-term pups. 



Feeding 



A to 



tal of 1 10 stomachs were examined, consisting of 

 34 males (576-1520 mm TL) and 76 females 

 (660-1746 mm TL). Females had a higher 

 percentage of empty stomachs (20.5%) than 

 males (12.1%). Preliminary analysis indi- 

 cated a change in diet with predator size. 

 This was investigated by grouping the data 

 into three arbitrary size classes: smaller 

 than >999 mm TL, 1000-1399 mm TL, and 

 >1400 mm TL and longer. Prey taken clearly 

 changes with increasing size ( Fig. 8 ). Although 

 invertebrates were important initially, larger 

 sharks took more vertebrates (Table 1). 



Small sharks fed almost entirely on crabs 

 (Fig. 8). The Cape rock crab, Plagusia 

 chabrus, dominated in the smaller two size 

 classes of shark, in terms of mass (78.3% 

 and 48.5%, respectively; Table 1). Larger 

 crustacean taxa appeared in the diet of 

 larger sharks. Cape slipper lobster, Scyl- 

 larides elisabethae, appeared in the second 

 size class and Cape rock lobster, Jasus 

 lalandii, and scalloped spiny lobster. Pan- 



