James et al.: Validation of the use of vertebrae and dorsal-fin spines for age determination of Squalus acanthias 45 
Table 1 
Tag-recapture data and band-pair counts for the 41 recaptured spiny dogfish 
(Squalus acanthias) that had a time at liberty (TAL) greater than 1 year and an 
oxytetracycline (OTC) mark in a vertebra. Specimens were tagged in the Gulf of 
Maine, on Georges Bank, and off southern New England during 2011 and 2012. 
Fork length at tagging (TFL), fork length at recapture (RFL), TAL, and other data 
are arranged by increasing TAL. 
TFL 
(em) 
RFL 
(em) 
Specimen 
ID code Sex 
SPD411 
SPD73 
SPD40 
SPD50 
SPD36 
SPD12 
SPD54 
SPD46 
SPD90 
SPD21 
SPD81 
SPD72 
SPD88 
SPD75 
SPD80 
SPD76 
SPD31 
SPD45 
SPD14 
SPD116 
SPD414 
SPD437 
SPD409 
SPD418 
SPD435 
SPD408 
SPD788 
SPD443 
SPD428 
SPD427 
SPD410 
SPD426 
SPD430 
SPD252 
SPD415 
SPD253 
SPD422 
SPD439 
SPD787 
SPD789 
SPD792 
67.0 69.9 
73.0 73.2 
76.0 76.6 
61.0 68.1 
71.0 73.8 
87.5 87.3 
72.0 70.0 
77.0 77.2 
80.0 79.6 
73.0 74.7 
72.4 73.0 
717.5 77.6 
79.8 717.9 
78.0 76.9 
74.0 74.7 
70.0 74.3 
66.0 67.5 
58.7 57.0 
67.5 65.8 
77.4 77.1 
82.1 83.2 
75.0 76.7 
75.0 75.5 
79.0 79.4 
73.0 75.4 
64.9 63.7 
72.0 70.0 
70.0 71.8 
65.2 64.4 
717.0 76.9 
75.0 76.9 
75.0 75.7 
68.0 67.5 
F 
F 
F 
F 
F 
F 
M 
F 
F 
F 
F 
F 
F 
F 
F 
F 
M 
M 
M 
F 
F 
F 
F 
F 
F 
M 
F 
F 
M 
F 
F 
F 
M 
M 
F 
M 
F 
F 
F 
F 
F 
and on specimens of Pacific spiny dogfish would lead to 
more robust conclusions. 
The absence of an OTC mark in wild specimens in mark- 
recapture studies is well-documented (e.g., Smith, 1984; 
McFarlane and Beamish, 1987). In our study, an OTC 
Date tagged 
3-Aug-2012 
16-Jul-2011 
12-Jul-2011 
14-Jul-2011 
17-Jul-2011 
13-Jul-2011 
16-Jul-2011 
13-Jul-2011 
16-Jul-2011 
17-Jul-2011 
27-Nov-2011 
17-Jul-2011 
12-Jul-2011 
13-Jul-2011 
16-Jul-2011 
17-Jul-2011 
14-Feb-2011 
10-Feb-2011 
11-Feb-2011 
27-Nov-2011 
2-Dec-2011 
12-Jul-2011 
1-Dec-2011 
2-Dec-2011 
15-Jul-2011 
26-Nov-2011 
4-Dec-2012 
5-Dec-2011 
2-Dec-2011 
27-Nov-2011 
13-Jul-2011 
2-Dec-2011 
16-Feb-2011 
16-Feb-2011 
16-Jul-2011 
17-Feb-2011 
16-Jul-2011 
16-Jul-2011 
16-Jul-2011 
16-Jul-2011 
1-Dec-2011 
TAL 
(years) 
1.05 
1.10 
1.11 
1.11 
1.12 
1.13 
1.16 
1.16 
1.17 
1.19 
1.20 
1.23 
1.28 
1.32 
1.32 
1.33 
1.49 
1.56 
1.58 
1.58 
1.60 
1.60 
No. of band 
pairs past 
OTC mark 
2.5 
mark was not found in many recaptured individuals in 
either vertebral centra or dorsal-fin spines, with OTC 
marking success rates of 47.1% and 30.4%, respectively. 
Other studies have had success rates for OTC marking in 
vertebrae ranging from 37.5% (Harry et al., 2013) to 100% 
