Natanson et al.: Resting population of Lamna nasus in the western North Atlantic Ocean 
73 
Table 2 
Collection data for female porbeagles (Lamna nasus ) caught between 2004 and 2018 off Massachusetts, in the general vicin¬ 
ity of Stellwagen Bank or off Cape Cod, and off the Grand Banks of Newfoundland, Canada. All organ measurements are 
presented in millimeters unless otherwise noted. A dash indicates that there were no data for a field. A single asterisk (*) in¬ 
dicates that the fish was abnormally thin, its organs were small for its length, and it was not used in analysis. Two asterisks 
(**) indicate that the fish was classified as postpartum. T=tournament; CFV=commercial fishing vessel; RFV=recreational 
fishing vessel. 
Maturity 
status 
Date 
captured 
Source 
Fork 
length 
(cm) 
Weight 
(kg) 
Upper 
oviduct 
width 
Oviducal 
gland 
width 
Uterus 
Uterus length 
width (upper) 
Uterus 
length 
(total) 
Ovary 
width 
Ovary 
length 
Maximum 
yolked egg 
diameter 
Membrane 
Ovary 
weight 
(g) 
Juvenile 
7/15/2017 
T 
202.0 
120.2 
4.8 
6.5 
8.3 
190 
260 
42.3 
71.7 
none 
Present 
99 
7/15/2016 
T 
204.1 
104.3 
3.2 
5.3 
8.3 
235 
Unk 
55.3 
53.5 
none 
Present 
73 
9/8/2016 
CFV 
215.7 
§§j 
8.6 
23.1 
46.3 
270 
520 
130.0 
180.0 
4.0 
Present 
264 
7/16/2016 
T 
218.2 
173.7 
6.5 
7.6 
30.4 
170 
325 
100.5 
107.2 
4.7 
Present 
158 
7/20/2013 
T 
219.4 
141.5 
- 
- 
- 
- 
- 
- 
- 
- 
- 
- 
7/20/2013 
T 
221.4 
142.0 
6.5 
19.5 
19.8 
- 
430 
85.0 
135.0 
none 
Present 
- 
7/13/2018* 
T 
234.7 
151.0 
4.2 
5.2 
10.0 
210 
320 
73.3 
87.2 
none 
Present 
98 
Adult 
7/13/2018 
T 
215.3 
152.9 
9.0 
23.2 
35.5 
235 
435 
120.0 
150.0 
none 
Absent 
204 
7/18/2008 
T 
217.5 
150.6 
12.3 
24.5 
41.4 
Unk 
460 
109.0 
158.0 
3.0 
Absent 
- 
7/22/2006 
T 
221.0 
146.5 
8.3 
25.0 
53.8 
240 
440 
130.0 
160.0 
3.1 
Absent 
340 
7/25/2009 
T 
223.0 
163.7 
9.5 
28.9 
49.7 
210 
440 
128.0 
180.0 
3.0 
Absent 
463 
7/18/2015 
T 
224.4 
160.6 
9.0 
20.9 
35.9 
190 
440 
115.0 
160.0 
none 
Absent 
- 
7/14/2017 
T 
227.0 
152.4 
8.3 
18.8 
26.4 
240 
470 
160.0 
158.0 
none 
Absent 
335 
7/16/2005 
T 
231.0 
171.5 
7.0 
20.9 
59.5 
310 
550 
165.0 
210.0 
3.5 
Absent 
545 
8/20/2011 
T 
233.0 
181.4 
9.6 
24.3 
64.4 
350 
500 
120.0 
180.0 
3.5 
Absent 
319 
7/20/2013 
T 
234.2 
177.4 
6.0 
22.2 
58.8 
- 
471 
140.0 
160.0 
none 
Absent 
- 
7/14/2017 
T 
237.7 
181.0 
8.4 
28.7 
53.8 
270 
512 
150.0 
150.0 
none 
Absent 
321 
7/15/2005 
T 
238.0 
171.5 
11.3 
24.4 
75.8 
290 
470 
150.0 
210.0 
3.2 
Absent 
448 
7/17/2004 
T 
239.0 
181.4 
7.6 
27.7 
62.9 
250 
320 
132 
195 
3.3 
Absent 
445 
7/22/2011 
T 
241.0 
224.5 
14.5 
22.4 
115.0 
290 
530 
145.0 
180.0 
none 
Absent 
668 
7/17/2015 
T 
241.0 
196.0 
8.3 
18.6 
74.2 
250 
485 
143.0 
225.0 
none 
Absent 
700 
9/20/2016 
CFV 
244.2 
11.7 
19.0 
70.4 
330 
569 
150.0 
160.0 
<i 
Absent 
394 
7/20/2012 
T 
247.0 
199.6 
7.3 
23.7 
60.8 
270 
515 
110.0 
190.0 
5.2 
Absent 
328 
9/7/2012** 
T 
247.6 
272.5 
7.4 
32.3 
140.0 
355 
- 
165.0 
252.0 
4.0 
- 
- 
9/20/2015 
RFV 
248.0 
219.1 
9.6 
32.5 
100.3 
390 
575 
130.0 
200.0 
4.0 
— 
650 
vaginal membrane, an indication that it had not previ¬ 
ously mated (mature virgin stage; Jensen et al., 2002), 
and a resting female has had prior mating experience 
and no vaginal membrane. A resting fish, as opposed 
to a recently postpartum fish, has recovered uteri, and 
its ovary no longer contains atretic oocytes; nor is its 
ovary hematose. The resting ovary has small, mostly 
non-yolked oocytes and is ready for vitellogenesis. In 
our study, maturity status of both sexes was assigned 
to each shark, at the time of dissection, on the basis 
of all previously described reproductive organ charac¬ 
teristics and was verified by comparison with measure¬ 
ments taken by Jensen et al. (2002) (Table 1; Suppl. 
Figs. 1—3) (online only). 
Data from Jensen et al. (2002) were reevaluated to 
determine whether resting females had been classified 
as adult without distinguishing the specific condition 
or maturity stage (i.e., resting versus pregnant). To 
attempt to determine stage, reproductive organ mea¬ 
surements from adult females not classified as either 
pregnant or ovulating were compared with those ob¬ 
tained from known resting females. Additionally, notes 
taken at the time of dissection were used in evaluat¬ 
ing the specific adult stage. Because it was known that 
these fish were adults, the distinction between stages 
had to be made between resting and ready-to-mate fe¬ 
males; therefore, the condition of the ovary, including 
maximum oocyte size, was the primary consideration. 
Only those fish for which their maturity stage could be 
firmly classified were used (i.e., specimens for which 
ovary data were not available were not reevaluated). 
Results 
Complete reproductive necropsies were conducted on 26 
female porbeagles (202.0-248.0 cm FL), of which 7 fish 
were immature (202.0-234.7 cm FL). Of the remaining 
19 mature individuals, 1 porbeagle (247.6 cm FL) was 
postpartum and 18 individuals were in a resting stage 
(215.3-248.0 cm FL; Table 2). The resting females ex¬ 
amined in this study had recovered uteri and ovaries 
