170 
Fishery Bulletin 111(2) 
Mismatched males (n= 25) were mature according to 
histology but immature macroscopically. 
Disagreements were for fish within the size range 
of transition from immature to mature (females: 42-49 
cm FL; males: 44-71 cm FL). Mismatches among fe- 
male classifications resulted in values of median size 
and age at maturity (L 50 and A 50 , respectively) that 
were 2.2 cm FL larger and 0.3 years older for histology- 
based results than for macroscopic classifications (mac- 
roscopic: L 50 =44.1 cm FL, A 50 =4.9 years; histological: 
L 50 =46.3 cm FL, A 50 =5.2 years) (Table 2). Mismatches 
among male classifications resulted in the L 50 and 
A 50 values that were 7.3 cm FL smaller and 1.0 year 
younger for histological examination than for macro- 
scopic results (macroscopic: L 50 = 54.1 cm FL, A 50 =5.9 
years; histological: L 50 =46.8 cm FL, A 50 =4.9 years) (Ta- 
ble 2). Therefore, a histological method not only shifted 
the median parameter estimates in opposite directions 
for each sex, but the magnitude of uncertainty due to 
method was much greater for males than for females 
(Table 3A). 
Maturity and spawning 
The fishery harvests immature fish of both sexes. Mac- 
roscopic collections indicated that 14% of females (32 — 
49 cm FL, 3-6 years old) and 38% of males (32-71 cm 
FL, 3-9 years old) caught on the 2008 sampled trips 
were immature. 
Histological classifications did not support differenc- 
es in L 50 or A 50 between sexes; however, macroscopic 
observations supported sexual dimorphism in the L r>0 
and A 50 parameters (Tables 2, 3B). These results likely 
mean that gonad histology detects hormonal matu- 
ration, a physiological state that occurs at a similar 
size and age for each sex but that may not be an ac- 
curate predictor of spawning activity for males. If so, 
then spawning activity, which is more closely aligned 
to measuring spawning stock biomass, occurred when 
males were 10 cm FL larger and 1 year older than fe- 
males, on average, in 2008 (Table 2; Fig. 7). 
Discussion 
This study confirms that the northern stock of Tilefish 
is functionally gonochoristic. Grimes et al. (1988) also 
concluded that this stock is gonochoristic, noting the 
presence of isolated oocytes in 2 of 50 testes. They did 
not report finding a lumen in testes, but they may have 
overlooked it, stating they were unsure about the sexu- 
ality of small fish with a lumen. We observed that the 
lumen was not always obvious in large fish, even when 
looking for it. The term “prematurational sex change” — 
where individuals express themselves as a female first 
but do not mature as a female before they switch to a 
male — does not seem to apply here. Instead, we believe 
that a testis containing a lumen is a common feature 
in Tilefish, as occurs for other fishes (e.g., Pomacentri- 
1.0 - 
ii in (i i! iii — ~ n i rr 
A :'r 
0.8- 
1 / 
0.6- 
// 
0.4 - 
, I , /4 95 =6.1 yr 
/ /; ^5o= 4 - 9 y 
0.2- 
/ / 1 ' A 5 =3.6 yr 
o.o- 
U U_J 
i i i 
o 0 5 10 15 
Q. 
1.0 - 
ii ii mi ii in n 
r 
B 
/ 
0.8- 
;7 / 
0.6- 
,7/ 
0.4- 
: : ^= 7.7 
yr 
/ 
^so^- 9 
yr 
0.2 - 
/ / 
cn 
II 
yr 
0 . 0 - 
1L 
B L 1 1 
0 5 10 15 
Age (years) 
Figure 7 
Maturity schedules of Tilefish ( Lopholatilus 
chamaeleonticeps) (A) females and (B) males col- 
lected in 2008 off southern New England for this 
study. Plotted are the predicted ogive (solid line), 
the 95% confidence limits (dashed lines), and 
individual data (internal tick marks, staggered 
relative to each other to reveal sample size). The 
median age at maturity (A 50 ) is listed, along with 
the age at which 5% (A 5 ) and 95% (A 95 ) of the 
individuals were mature. Ages >15 years were 
grouped. 
dae and Serranidae; Sadovy and Domeier, 2005), but is 
unrelated to function. We also do not categorize Tilefish 
as bisexual — a term that does not apply with the ap- 
pearance of a lumen or the presence of isolated oocytes 
as described here (Sadovy and Domeier, 2005). 
Our conclusion about gonochorism emphasizes func- 
tion; in other words, all individuals reproduce exclu- 
sively as either male or female during their lives (Sa- 
dovy de Mitcheson and Liu, 2008). Because we sam- 
pled fish during the spawning period, and functional, 
