Fishery Bulletin 119(4) 
53 53 51 50 43 
44 
Mean marginal increment ratio 
51 51 71 439 437 
11 
8 12 
E 
36 64 69 24 
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 
Figure 6 
Monthly mean marginal increment ratios for black sea bass (Cen- 
tropristis striata) caught in the Atlantic Ocean off the northeast- 
ern United States during 2013-2017, for (A) age bin 1 (ages 1-2), 
(B) age bin 2 (ages 3-4), and (C) age bin 3 (ages 5+) and for the 
regions (D) north and (E) south of the Hudson Canyon. Numerals 
above data points denote the number of samples for each month. 
Error bars indicate 2 standard errors of the mean. 
Results of assessment with AIC values for the Okamura 
et al. (2013) circular-linear models (hereafter referred to 
as the Okamura analysis) indicate that 1 cycle was com- 
pleted within a time span of 1 year for each age bin and 
both regions (i.e., model A had the lowest AIC values for 
all iterations). This finding confirms results from the 
interactive models and mean MIR visualizations, which 
indicate that the MIR reaches one minimum per year 
(Figs. 5, 6, and 7). 
Young of the year: measurements and 
length—frequency analysis 
Radius measurements of otoliths from age-0 sam- 
ples collected in the fall were smaller than the 
first annulus measurements of age-1 samples 
(t =-11.92, df=67, P<0.0001). The mean radius of 
otoliths from age-0 fish was 0.36 mm, compared 
with a mean annulus measurement of 0.60 mm for 
otoliths from age-1 samples. The first annulus mea- 
surements of otoliths from age-1 samples collected 
in summer were similar to the first annulus mea- 
surements of otoliths from all MIA samples (¢=1.01, 
df=37, P=0.3205). Measurements of the first annu- 
lus (for all samples used in MIA, n=1299) range 
from 0.41 mm to 0.92 mm with a mean of 0.61 mm. 
Mean first annulus measurements were similar 
between regions (f=—1.19, df=629, P=0.2365), at 
0.61 mm for otoliths of samples from the region 
north of the Hudson Canyon and 0.62 mm for oto- 
liths of fish from the region to the south. 
Results of modal length—frequency analysis done 
with data from the resource assessment and vent- 
less trap surveys confirm that samples used for 
first annulus validation were YOY (Fig. 8). A dis- 
tinct modal separation between ages was apparent 
in the samples used for MIA, and length modes of 
the smallest fish overlapped in each survey. Mea- 
sured lengths of age-0 fish collected in the fall and 
used in this study were from 35 to 120 mm TL, 
comparable to the length range for the first mode 
of fish captured in the fall during the resource 
assessment survey, from 20 mm TL to approxi- 
mately 125 mm TL (Fig. 8A). Age-1 fish caught 
in summer and used in this study had lengths of 
110-207 mm TL; whereas, lengths of the smallest 
mode of black sea bass collected in summer during 
the ventless trap survey were 60 mm TL to approx- 
imately 180 mm TL (Fig. 8B). 
Discussion 
Annulus periodicity and timing 
The results of this study verify that one opaque 
band and one translucent band were deposited 
per year in otoliths of black sea bass. One clear 
minimum MIR was observed, and otolith growth 
continued throughout the year for samples in 
each age bin and from both regions. This sinusoidal pat- 
tern is consistent with results of other MIA studies that 
have confirmed that one annulus is deposited per year 
(Wenner et al., 1986; Vilizzi and Walker, 1999; Pilling 
et al., 2000). Additionally, the Okamura analysis con- 
firmed these results, also indicating that 1 cycle occurred 
per year in each age group and in each region. 
Annulus deposition is considered finished when new 
translucent growth is observed at the otolith edge. In other 
