32 
Fishery Bulletin 120(1) 
Table 3 
Ranges of measurements and descriptions of organs used to determine maturity stages of male blue sharks (Prionace 
glauca) captured in the western North Atlantic Ocean between New Jersey and the Flemish Cap during 1971-2016. 
Sharks in the size ranges associated with the immature and mature stages generally conform to those assignments 
(unless otherwise noted); whereas, sharks in the transitional size range can be either immature or mature and rep- 
resent the size of the smallest mature and largest immature fish. The table format is adapted from Walker (2005). 
n=number of samples. 
Range of 
measurement 
Organ (mm) Description 
Left clasper length <99 
(n=434) >99 to <135 
Epididymis width <13 
(n=330) >13 to <23 
Testis length <105 
(n=322) >105 to 190 
(Table 3). Sperm and spermatophores were observed in all 
mature males for which this factor was examined. 
Median maturity analysis 
Females Variation in size at maturity for females was 
best described by maturity ogives based only on FL or 
weight, indicating no evidence of difference in L;) or Wz 
between time periods (Table 4, Suppl. Table 2 [online only]); 
therefore, all data from 1971 through 2016 were used to 
define the size at median maturity. On the basis of matu- 
rity ogives, the size at median maturity of female blue 
sharks is 190.9 cm FL and 50.1 kg (Table 4, Fig. 2). 
Males Contrary to the results for females, results from 
the best fitting model for males indicate an increase in Ls 
and W,;,. between time periods (Table 4, Suppl. Table 2 
Soft and uncalcified, resists rotation and flexing of the tip 
Soft or plastic, begins to rotate 
2135 Calcified, easy rotation and flexing of the tip 
Thin and straight 
Coiling begins 
<23 Thickened and heavily coiled 
Thin, encompassed in epigonal tissue 
Thinning epigonal tissue, elongated 
>190 Elongated, distended 
Maturity 
stage 
Immature 
Transitional 
Mature 
Immature 
Transitional 
Mature 
Immature 
Transitional 
Mature 
[online only]). Estimated median maturity for TP2 occurred 
at 211.2 cm FL and 62.3 kg, which represent rather large 
increases from TP1 (184 cm FL and 35.6 kg). Upon fur- 
ther examination, there appeared to be clear differences 
in the sampled size distribution between time periods, 
with TP2 having more large fish (>220 cm FL) and fewer 
samples in the range of 160—220 cm FL than TP1 (Table 4, 
Fig. 3). The absence of juvenile males in the range of 220-— 
240 cm FL during TP1, and the presence of juvenile males 
in the range of 220-240 cm FL during TP2, may indicate 
an increase in size at maturity over time. However, there 
is evidence of large juveniles in the interim period (1978— 
2002), and this evidence indicates that large juveniles 
were in this size range prior to TP2 and were probably 
under-sampled because of low sample size in this size 
range in TP1. Because the large juvenile males were 
present, the difference observed between TP1 and TP2 is 
Table 4 
Median fork length (FL in centimeters) and weight (in kilograms) at maturity (L5) and Wso, respectively) and size range (in centi- 
meters and kilograms) of blue sharks (Prionace glauca) captured in the western North Atlantic Ocean between New Jersey and the 
Flemish Cap. Sampling occurred in 2 time periods: 1971-1977 (TP1) and 2003-2016 (TP2). Values are also provided for the interim 
period of 1978-2002. n=number of samples. 
Size range (cm FL) Ls Size range (kg) Ws0 
Female n Male n Female Male 
Female Male 
Period Female n Male n 
TPl 108.0—263.0 134 102.0-279.0 155 190.6 184.1 91-1125 80 17.7-1225 33 50.8 35.6 
TP2 114.0-273.0 110 64.7-300.0 224 189.8 211.2 1.7-110.0 56 1.4-213.4 199 43.5 62.3 
TPlandTP2 63.1-257.2 244 64.7-300.0 379 189.8 191.2 1.7-112.5 136 1.4-213.4 232 48.3 50.7 
1971-2016 63.1-273.0 315 62.0-300.0 488 190.9 192.5 1.7-146.0 188 1.0-213.4 319 50.1 49.5 
