46 



Fishery Bulletin 98(1) 



40 - 

 30 

 20 

 10 

 

 40 



c 30 - 



2 20 -I 



10 

 

 80 

 60 

 40 

 20 

 



^fl Males {n 



I Females 



I Total {n = 



(n = 608) 



50 75 100 125 150 175 200 225 250 



Fork length (cm) 



Figure 3A 



Porbeagle length-frequency distributions by sex for April-July: (A) 

 southwest New Zealand; (Bl northeast New Zealand; (Cl Australia. 

 The bottom panel in each series includes some unsexed sharks, n = 

 sample size. Triangles indicate mean lengths of the age classes identi- 

 fied by MIX modal decomposition. 



hog^giweight) ^ -5.050 + 3.128 Logjt, (FL), 



(n= 641, r-=0.956) 



where weight is expre.ssed in kg and FL in cm. 



In New Zealand, length ranges were 64-228 cm for 

 males and 61-206 cm for females (Fig. 3, A and B). 

 Most were shorter than 150 cm. The size distribu- 

 tions were similar for males and females up to 150 cm, 

 and the sex ratio (both subregions combined) was not 

 significantly different from one (M:F=0.93:1; ;t:^=1.99, 

 P>0.1). However, males outnumbered females above 

 150 cm by 3.18:1 (;t:''^= 16.28, P<0.01). 



In southwest New Zealand, there was a strong modal 

 peak at 79-93 cm for both sexes, and for males there 

 were also clear peaks at 100-115 cm and 118-133 cm 

 (Fig. 3A). The best MIX fit to the combined .sexes data 

 consisted of three age classes whose mean lengths are 



shown in Fig. 3A. Sample sizes were small in north- 

 east New Zealand; therefore no MIX model was ap- 

 plied. A strong mode was present at 67-88 cm (Fig. 

 3B), and indistinct modes were present for both sexes 

 at about the same position as the second and third 

 modes in southwest New Zealand. 



In Australia, length ranges were 61-204 cm for 

 males and 58-208 cm for females (Fig. 3C). Most 

 were shorter than 150 cm, with a strong mode at 

 76-94 cm. The size distributions of males and fe- 

 males were similar. The sex ratio of sharks smaller 

 than 150 cm did not differ significantly from one 

 ( 1.07:1; /2=i.47, p>0.1), but males outnumbered fe- 

 males above 150 cm by 2.71:1 (;f'^=11.08,P<0.01). The 

 best MIX fit to the combined sexes data consisted of 

 five age classes whose mean lengths are shown in 

 Figure 3C. 



