CROSS: BIOLOGY OP^ SCYLIORHINID SHARKS 



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Figure 7.— Mean gonadosomatic index (GSI) of Parmaturus 

 xaniurus males (above) and females (below) from December 1983 

 through November 1984. Cross-hatched bar indicates months when 

 females were carrying egg cases. Vertical bars are 95% confidence 

 intervals. 



oocytes were present in the right ovary of females 

 every month except July (Fig. 8). The number of 

 oocytes larger than 4 mm was correlated with size 

 among mature females (r = 0.597, P < 0.001); the 

 maximum number was 23. Atretic oocytes were ob- 

 served in May, August, and November and spent 

 fish (no oocytes larger than 3-4 mm; A^ = 3) were 

 collected in January and March. 



Egg cases were present in the oviducts of five P. 

 xaniurus females larger than 470 mm (10% of 

 mature females); the egg cases were not complete- 

 ly formed in one individual. One 450 mm TL female 

 had recently released two egg cases as evidenced 

 by distended oviducts. Egg cases were present in 

 females collected in December, January, August, 

 and November (Fig. 7). The mean ratio of egg case 

 length to female total length was 0.156 (SD = 

 0.023). 



Food Habits 



Stomachs from 211 A. brunneus were examined; 

 138 (65%) were empty or contained only traces of 



OOCYTE DIA (MM) 



Figure 8.— Mean monthly oocyte (>4 

 mm) size-frequency distribution oi Par- 

 maturus xaniurus from December 

 1983 (bottom) to November 1984 (top). 

 Sample size in parentheses. 



well-digested prey. There was no seasonal trend in 

 the proportion of empty stomachs. Crustaceans, 

 teleosts, and molluscs constituted the diets of the 

 remaining individuals (Table 3). Natantian decapods 



697 



