McBride et al.: Changes in size and age at maturity of the northern stock of Lopho/atilus chamae/eonticeps 
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Table 1 
Macroscopic criteria for classifying maturity of Tilefish ( Lopholatilus chamaeleonticeps ), modified from Idelberger (1985: 
table 1), with references to new microscopic observations from gonad histology of Tilefish sampled in 2008 off southern New 
England for this study. 
Maturity class 
Description of ovary 
Description of testes 
Immature 
Ovaries are small and transparent, becoming 
increasingly yellowish, rounded, and veined at 
the surface as fish nears maturity. Gonads 
compose <0.5% of body weight. 
Testes consist of very narrow, transparent bands of 
tissue, composing <0.05% of body weight. Histological 
sections reveal isolated oocytes in a low percentage 
of young males. 
Developing 
Ovaries are firm, bulbous, yellow to light orange 
in color, and 0. 5-2.0% of body weight. 
Vitellogenic (yolked) oocytes (0.3-0. 7 mm in 
diameter) are visible through the gonad wall. 
Gonads become opaque white, increasing modestly 
in size (0.03-0.12% of body weight). 
Ripe 
Enlarged gonads (1. 0-5.0% of body weight) 
become lobular and have a speckled appearance. 
A homogenous mixture of vitellogenic and mature 
(hydrated; 0. 7-1.0 mm) oocytes are evident 
through the gonad wall. 
Further enlarged (0. 1-0.2% of body weight) although 
still relatively small organs; long, flattened, and 
opaque milky white with phosphorescent sheen. 
Running ripe 
Ovaries are turgid and compose 5.0-10.0% of 
body weight. Gonads have a granular yellow 
appearance from vitellogenic oocytes in the 
lamellae and a transparent lumen containing 
hydrated oocytes, visible ventrally. Eggs 
(-1.2 mm) flow freely from the vent without 
any or only light pressure to the abdomen. 
Sperm released with light abdominal pressure was 
diagnostic of this maturity class, although it also was 
observed rarely, even among the largest fish. 
Spent 
Gonads are reddish-orange, flaccid, and reduced 
to 0. 5-1.0% of body weight. 
Slightly flaccid and reduced to 0.04-0.07% of body 
weight. 
Resting 
Ovaries are uniformly yellow in color, becoming 
firm, composing 0. 5-1.0% of body weight. 
Indistinguishable from developing testes. 
Training included testing for aging precision (i.e. , re- 
peatability of age assignment by different readers to 
the same otolith). Precision was first measured by per- 
cent agreement, 
A 
Percen t agreement = 100 x — , ( 1 ) 
N 
where A = the number of replicate ages in agreement 
(of 2); and 
N = the total number of fish aged. 
Precision also was evaluated with Chang’s coefficient of 
variation (CV; Chang, 1982): 
CV = 100 x 
1 % \ 
N “ 
7=1 
2 (X 
y '7 
,=i R - 1 
X, 
XjY 
( 2 ) 
where N = the total number of fish aged; 
X t/ = the /th age determination (i.e., of 2) of the 
jth fish; and 
X = the mean age estimate of the yth fish. 
m - 1 m (/I - n ) z 
y y y V Ji ’ 
(=i j=i + 1 n . + n 
(3) 
where m = the maximum age in the data set; and 
n = the number of fish in the /th row and yth 
column, etc. 
These precision tests also were used to evaluate 
repeatability of multiple readings by the primary age 
reader. In terms of final age assignment, when the 
first 2 readings from each otolith collected in 2008 dis- 
agreed, a third reading was performed. The value that 
occurred twice was used as the final age (i.e., there 
were no situations in which the third reading was dif- 
ferent from both of the first 2 readings). 
Models and analysis 
Generalized linear models were programmed with R, 
vers. 2.15.2 4 (R Core Team, 2012), to estimate param- 
eters of maturity ogives. A full range of immature and 
mature fish, by size and age, was collected, making pa- 
rameter estimation straightforward (Trippel and Har- 
Bowker’s test was used to detect departures from sym- 
metry between the new reader and the reference col- 
lection, with the formulation of Hoenig et al. (1995): 
4 Mention of trade names of commercial companies is for iden- 
tification purposes only and does not imply endorsement by 
the National Marine Fisheries Service, NOAA 
