FISHERY BULLETIN: VOL. 86, NO. 4 



sets {t = 0.56, P > 0.05), but A. brunneus were more 

 abundant than P. xaniurus on mud sets (t = 3.50, 

 P < 0.01) (Table 1). 



Apristurus brunneus occurred on 61% of the bank 

 sets and 79% of the mud sets. Catches were not 

 significantly different among habitats, seasons, or 

 depths (ANCOVA, P > 0.05). Mean catch per tub 

 in the mud habitat was not significantly different 

 between floating and sinking sets {t = 1.35, P = 

 0.19). 



Parmaturus xaniurus occurred on 73% of the 

 bank sets and 76% of the mud sets. Catches were 

 significantly higher on bank sets than on mud sets 

 (ANCOVA, P < 0.05). Catches were nearly twice as 

 high on bank sets in the winter compared with bank 

 sets in the summer. Catch increased with increas- 

 ing depth on banks, but it decreased with increas- 

 ing depth on mud. Catches on the mud were not 

 significantly different between floating and sinking 

 sets {t = 0.76, P = 0.45.). 



Size 



There were no significant differences in the 

 regression coefficients of the weight-length relation- 

 ships between males and females of either A. brun- 

 neus or P. xaniurus over the range of sizes ex- 

 amined (Table 2; Fig. 2). There were no significant 

 differences in the size of A. brunnetis or P. xaniurus 

 among habitats, seasons, or depths (ANCOVA, P 

 > 0.05). 



Table 1 .—Catch statistics for Apristurus brunneus and Parmaturus 

 xaniurus from longline collections on banks and mud. No^ = 

 number, wt = weight in kg, N = number of positive sets, X = 

 mean, SD = one standard deviation. 



Reproduction 



Based on relative change in clasper length and 

 gonad weight, A. brunneus males reached sexual 

 maturity between 450 and 500 mm TL; P. xaniurus 

 males reached sexual maturity between 375 and 425 

 mm TL (Fig. 3). Females of both species reached 

 sexual maturity between 425 and 475 mm TL (Fig. 

 4). Only the right ovary was functional in both 

 species. 



Seasonal changes in gonadal development were 

 not pronounced among A. brunneus. Male and 

 female GSIs were highest in winter and lowest in 

 summer (Fig. 5). Large oocytes were present in the 

 right ovary of females throughout the year (Fig. 6). 



350 400 450 500 550 600 650 



300 350 400 450 500 550 600 

 TOTAL LENGTH (MM) 



Figure 2.— Weight-length relationships oi A-pristurus brunneus 

 (above) and Parmaturus xaniurus (below). 



Table 2.— Geometric mean weight-length regressions for Apristurus brunneus and 

 Parmaturus xaniurus. N - sample size, min = minimum total length (TL) in mm, 

 max = maximum TL, W = body weight in g, /. = TL, LI = lower 95% confidence 

 interval for b, L2 = upper 95% confidence interval, r = correlation coefficient. 



Species Sex N min max 



W = aL^ 



LI 



L2 



A. brunneus 



P. xaniurus 



F 

 M 



F 

 M 



149 

 90 



76 

 89 



369 

 389 



307 

 325 



556 

 625 



574 

 516 



W = 2.379 X 



W = 3.577 X 



W = 9.377 X 



W = 3.163 X 



10"® ; 3 059 



2.839 

 2.809 



3.045 

 3.166 



3.279 

 3.134 



3.439 

 3.688 



0.899 

 0.966 



0.965 

 0.934 



694 



