McBride et al.: Changes in size and age at maturity of the northern stock of Lopholatilus chamae/eonticeps 
169 
Table 2 
Median fork length (L 50 , cm) and age (A 50 , years) at maturity, standard error (SE), range, and sample size (n) of Tilefish 
( Lopholatilus chamaeleonticeps) collected in 2008 off southern New England — by year, sex, and method used to evaluate 
maturity. The methods used were macroscopic evaluation of the whole gonad and microscopic evaluation of gonad histology. 
Raw data from 1978 and 1982 are extracted from Grimes et al. (1988: tables 3-6; see text for details). Predicted ages at 
maturity from tabulated data in Grimes et al. (1988) also are plotted in Figure 2. 
Year 
Sex 
Method 
^50 
SE 
Range 
n 
"^50 
SE 
Range' 
n 
2008 
Male 
Macroscopic 
54.1 
1.4 
32-100 
99 
5.9 
0.2 
3-23 
99 
2008 
Male 
Histological 
46.8 
1.5 
32-100 
99 
4.9 
0.2 
3-16 
99 
2008 
Female 
Macroscopic 
44.1 
1.1 
32-90 
58 
4.9 
0.2 
3-25 
58 
2008 
Female 
Histological 
46.3 
1.2 
32-90 
58 
5.2 
0.2 
3-21 
58 
1982 
Male 
Macroscopic 
38.6 
4.6 
41-95 
241 
4.6 
0.8 
4-12 
88 
1978 
Male 
Macroscopic 
62.6 
1.0 
31-115 
384 
7.1 
0.2 
4-15 
246 
1982 
Female 
Macroscopic 
49.8 
0.4 
26-100 
360 
5.5 
0.2 
4-15 
121 
1978 
Female 
Macroscopic 
45.4 
1.2 
31-95 
393 
5.2 
0.1 
4-15 
267 
'Ages >15 years were grouped because Grimes et al. ( 1988) had grouped ages at this value in their data tables. 
Maturity methods compared 
Before we compared maturity schedules between years, 
we evaluated a potentially confounding effect on esti- 
mation of maturity of Tilefish: the effect of method. 
There was a general agreement in maturity classifi- 
cation (i.e., immature versus mature) between mac- 
roscopic and microscopic (histological) methods. When 
both methods were used on the same fish, the agree- 
ment was higher for females (94%) than for males 
(84%). Mismatched females (n= 4) were immature ac- 
cording to gonad histology but mature macroscopically. 
Table 3 
Comparisons of different data aggregates in testing for the effect of fish size (fork length [FL], cm) or age (years) on 
maturity of Tilefish ( Lopholatilus chamaeleonticeps). The first comparison tests the effect of (A) method, macroscopic 
(macro) versus histological (histo), in evaluation of maturity status of fish collected in 2008 off southern New England 
for this study (controlling for factors of sex, M=male; F= female). The next comparison tests for (B) sexual dimorphism 
(by method with data from examination of fish collected in 2008). The last 2 comparisons test whether macroscopic 
estimates of maturity (used in all years) were different in 2008 than they were in (C) 1982 and (D) 1978, by using 
historic data for 1978 and 1982 from Grimes et al. (1988). See Table 2 for fitted parameter values by year, sex, and 
method. “Units” are modeled as a covariate, either as a main effect ( + ) or an interaction (*). Model sets are evaluated 
row-wise, with the second-order Akaike’s information criterion (AIC c ) value. The lowest AIC c value, indicating the 
least uncertainty, is underlined. If AAIC c values are <2, indicating the effects are indistinguishable, both or all cells 
are underlined. 
AIC c values of full and reduced models 
Units compared 
(covariates) 
Other 
Length models 
Age models 
factors 
FL* units FL+ units 
FL 
Age* units 
Age+ units 
Age 
A 
Method (macro/histo) 
M, 2008 
86.8 
85.0 
97.1 
94.9 
93.4 
104.2 
Method (macro/histo) 
F, 2008 
55.8 
53.9 
53.8 
68.5 
66.5 
66.0 
B 
Sex ( male/female) 
Macro, 2008 
74.7 
74.9 
95.8 
87.3 
85.9 
93.7 
Sex (male/female) 
Histo, 2008 
67.9 
66.1 
64.2 
76.1 
74.1 
73.8 
C 
Year (1982/2008) 
M, Macro 
305.3 
323.9 
329.4 
143.4 
153.1 
151.8 
Year (1982/2008) 
D 
Year ( 1978/2008) 
F, Macro 
189.8 
187.8 
208.4 
78.7 
77.2 
78.8 
M, Macro 
353.5 
356.6 
369.7 
248.9 
249.6 
261.5 
Year (1978/2008) 
F, Macro 
344.8 
353.8 
352.8 
230.0 
229.8 
229.7 
