McBride et al : Changes in size and age at maturity of the northern stock of Lopholatilus chamaeleonticeps 
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simultaneous hermaphroditism was not observed, this 
type of hermaphroditism is unlikely. We did not sam- 
ple in winter to test for sequential sex change during 
the nonspawning period, but the histological evidence 
of similar A 50 for both functional sexes makes this 
change unlikely. We predict that intersex fish would 
be no more common during the nonspawning season 
than they are reported herein for the spawning season. 
Also, we predict that, if collections of younger (<3 years 
old) fish were possible, isolated oocytes would be more 
commonly seen because isolated oocytes were observed 
to be degrading in our collections of testes. If these 
predictions about morphology are correct, they would 
confirm our conclusions that Tilefish are functionally 
gonochoristic. Erickson and Grossman (1986) investi- 
gated the sexual pattern of Tilefish farther south, in 
Atlantic waters of the Georgia Bight, and also conclud- 
ed that Tilefish are functionally gonochoristic. In con- 
trast, Lombardi-Carlson (2012) reported higher rates of 
intersex Tilefish in the Gulf of Mexico, evident for both 
functional males and females; therefore, there appears 
to be geographic variation in the morphological expres- 
sion of intersex fish and possibly the sexual pattern by 
Tilefish. 
Our study is the first attempt to age the north- 
ern stock of Tilefish in nearly 30 years. Turner et al. 
(1983) reported ages of fish collected in the longline 
and recreational fisheries in 1978, and Turner (1986) 
reported ages from the longline fisheries in 1979, 1980, 
and 1982. Females older than 31 years were collected 
in each of these sampling years, and males older than 
31 years were collected in half of these years (Turner, 
1986: appendix 1, A-H). The oldest fish observed was 
46 years old (Turner, 1986), nearly twice as old as the 
oldest fish observed in 2008 in our study. Age structure 
during 1978-82 also appeared to be dominated by the 
1970 and 1973 year classes, but dominant year classes 
(the most recent one being 1999; NEFSC 3 ) were not ob- 
vious from the age structure measured in 2008 (Fig. 6). 
The reduced numbers of older fish today indicate that 
age truncation still exists, a finding that should not be 
surprising because landings >1000 t persisted well into 
the 1990s. We predict that fish older than 30 years will 
return to the population in the next decade. 
The effect of method (macroscopic versus histologi- 
cal) in determination of maturity was more pronounced 
for males than for females (Tables 2, 3A). Differences 
in the 2008 female L 50 and A 50 attributable to method 
were minor (2.2 cm FL, 0.3 year). Our confidence in 
macroscopic evaluation of maturity was good at this 
time of year, when the main histological criterion, vi- 
tellogenic oocytes, were large enough (0.3-0. 7 mm) to 
be seen macroscopically; hydrated oocytes were even 
more readily visible: 0. 7-1.0 mm (as measured from 
histological slides by T. Vidal, unpubl. data). Data for 
females at other times of the year, especially during 
the nonspawning season, are likely to be less precise 
or accurate (Vitale et al., 2006; McBride et al., 2013). 
That the observed differences in L 50 and A 50 attrib- 
uted to method were larger for males (7.3 cm FL, 1.0 
year) than for females was not unexpected. Grimes et 
al. (1988) also observed larger and older male L 50 and 
A 50 with a macroscopic method versus a histological 
method. We agree with Grimes et al. (1988): these dif- 
ferences in male maturity are not merely a method- 
ological artifact but are of biological significance — like- 
ly the result of a physiological lag in gonad growth and 
the time that exists between spermiation (an indica- 
tion of hormonal activity) and full ripening of the tes- 
tes that precedes functional spawning by males. Such a 
lag may also be associated with behavioral differences. 
Grimes and Turner (1999) postulated that males first 
mature in a subordinate role and become dominate 
within 1-2 years. 
Although such hypotheses demand further study, 
it is obvious that the method to determine maturity 
can matter in comparative analyses. The macroscopic 
method is likely aligned with functional spawning, and 
functional spawning more accurately defines spawn- 
ing stock biomass. Therefore, it is the more appropri- 
ate method to use in routine measures to characterize 
this reference point for males. Grimes et al.’s (1988) 
approach emphasized the macroscopic method; there- 
fore, our comparisons with relatively large sample sizes 
should be robust between all years (i.e. , 1978, 1982, 
2008), 
The large percentage of immature Tilefish in the 
catch (14-38%, by sex) appears to point to violation of 
the principle to let fish reproduce at least once before 
they are harvested (Sissenwine and Shepherd, 1987). 
Although it is once again a topic of debate (Garcia et 
al., 2012), this principle prompts a re-evaluation of the 
effect of hook size on the proportion of immature fish 
landed. 
Female size at maturity differed between 2008 and 
earlier years, but female age at maturity did not differ 
strongly between years (Tables 2, 3[C and D|). Female 
L 50 was smaller in 2008 (44.1 cm FL) than in 1978 
(45.4 cm FL) and 1982 (49.8 cm FL). The difference in 
A 50 between all years was <1 year, and the low AIC c 
score (i.e., <2) indicated that these differences in fe- 
male A 50 over time were similar. Nonetheless, female 
fitness is related to size and age (Green, 2008). In our 
study, the youngest A 50 was measured in 2008. Other 
studies have shown that such shifts in maturity sched- 
ules are associated with reduced yield, survival, and 
fecundity (Law, 2000; de Roos et al., 2006; Conover et 
al., 2009). In particular, the mature female Tilefish that 
showed no immediate evidence of spawning were young 
(5-6 years old), indicating that newly matured females 
have lower spawning frequency and, therefore, a lower 
reproductive potential than older females. Age-specific 
effects on spawning frequency and batch fecundity are 
commonly observed in fishes and can alter stock as- 
sessment outcomes (Fitzhugh et al., 2012), and there- 
fore continued research is warranted to clarify such 
