82 
Fishery Bulletin 1 14(1) 
labile 1 
Summary of results of the bomb radiocarbon analysis of otoliths from wreckfish 
(Polyprion americanus) that were collected in the North Atlantic in 1991. The last 
column provides the standard errors (SE) associated with the A 14 C (%c) values. An 
asterisk (*) indicates that 2 sections were used to meet the weight requirement for 
processing otoliths with accelerator mass spectrometry. 
Collection 
number 
Number 
of growth 
increments 
Birth year 
Weight (mg) 
of 
otolith core 
A 14 C (%c) 
SE 
910086-18 
43 
1948 
11.5 
-63.36 
2.5 
910076-15 
40 
1951 
13.2 
-14.98 
4.5 
910084-5 
40 
1951 
10.7 
-67.43 
2.2 
910085-14 
40 
1951 
8.5 
-60.97 
2.5 
910084-11 
36 
1955 
11.2 
-60.35 
2.5 
910078-11 
34 
1957 
9.6 
-57.15 
3.5 
910082-32 
29 
1962 
11.3* 
-64.32 
2.5 
910086-2 
27 
1964 
8.9 
-63.87 
2.7 
910083-46 
26 
1965 
12.8 
-18.90 
2.5 
910076-5 
25 
1966 
15.2 
-18.47 
4.8 
910078-17 
23 
1968 
9.6 
20.67 
2.5 
910076-2 
22 
1969 
15.1* 
47.48 
4.4 
910078-28 
22 
1969 
9.4 
98.90 
2.7 
910083-13 
22 
1969 
11.0 
57.52 
2.5 
910079-10 
20 
1971 
12.4 
35.80 
2.5 
910079-16 
18 
1973 
16.7* 
65.90 
3.4 
910079-14 
17 
1974 
12.8* 
72.14 
2.9 
910086-1 
16 
1975 
8.6 
87.13 
2.7 
910085-6 
15 
1976 
9.5 
80.04 
4.4 
910080-19 
11 
1980 
10.1 
90.88 
2.7 
and birth years (based on one increment formed per 
year) ranging from 1948 to 1980 (Table 1). The otolith 
core weights ranged from 8.5 to 16.5 mg; however, 4 
samples required the use of a second section to meet 
the requirement for the minimum material needed for 
analysis with accelerated mass spectrometery. Otolith 
core values of A 14 C ranged from -7.43%e in birth year 
1951 to 98.90%c in birth year 1969, well within the 
range of previously published A 14 C levels from had- 
dock (Campana, 1997). Levels of A 14 C in otolith cores 
from wreckfish showed a prominent increase beginning 
in the early 1960s, peaking around 1975 and leveling 
off thereafter (Fig. 3A). There was no evidence of the 
expected decline in A 14 C levels after 1975, possibly as 
a result of the lack of sufficient samples past that date. 
Wreckfish with birth years before 1963 exhibited rela- 
tively constant low levels A 14 C, with the exception of 
one outlier fish that had an estimated birth year of 
1951 (A 14 C= -14.98%c). Another possible outlier was a 
fish with a birth year of 1969 ( A 14 C=98.90%e). Because 
most samples exhibited a good fit to the logistic re- 
gression curve, we believe the outliers resulted from a 
contamination issue during core removal rather than 
from aging error. 
The % 14 C uptake chronology for wreckfish (a=0.87, 
P=1967, A,=1.31) exhibits an uptake pattern similar in 
shape to the published % 14 C chronology for haddock 
(a=0.93, (3=1962, A=2.35) (Campana, 1997; Fig. 3B). 
However, the fitted logistic curve for % 14 C of wreckfish 
fell below the fitted logistic curve for % 14 C of haddock 
for the entire time period (Fig. 3B), and there was a 
noticeable phase shift of 5-6 years between the models 
(wreckfish (5=1967 and haddock (1=1962). The variance 
ratio test confirmed that the curves were significantly 
different (jP< 0.001). Despite the small difference in 
curves, which indicates potential underaging, the simi- 
larity in uptake patterns between the 2 curves indi- 
cates annual growth increments. 
Age and growth 
After completion of all otolith readings (n=568) for age 
and growth analysis, we omitted 14 otoliths because of 
disagreements between readers. Specimens ranged in 
size from 452 to 1340 mm FL (Fig. 4.). Ignoring the po- 
tential phase shift identified in the bomb radiocarbon 
validation study, ages of wreckfish ranged from 1 to 80 
years for reader 1 and from 2 to 79 years for reader 
2, with an average disagreement of 4 years. Readers 
produced identical counts 10.8% of the time, had agree- 
ment within 1 year 30.4% of the time, and had agree- 
ment within 5 years 72.7% of the time, a considerable 
improvement over the bomb radiocarbon readings. This 
improvement resulted from the development and use 
