94 
Fishery Bulletin 1 1 1 (1) 
Table 2 
The reproductive maturity index developed and used in this study of staging methods for female Haddock (Melanogrammus 
aeglefinus ) during histological analysis with analogous stages from the macroscopic field index. Histological definitions were 
based on criteria of Brown-Peterson et al. (Table 2 in 2011) CA=cortical alveolar; GVM=germinal vesicle migration; GVBD= 
germinal vesicle breakdown; NA=not applicable; OM=oocyte maturation; POF=postovulatory follicle; SC*=spawning capable, 
actively spawning subphase; Vtgl=primary vitellogenic; Vtg2=secondary vitellogenic; Vtg3=tertiary vitellogenic. 
Histology 
Stage 
Macroscopic 
Histological description 
Immature 
Developing (early 
1.0 
1 
Small ovaries, only oogonia and primary growth oocytes present. Ovary wall 
thin, no muscle bundles evident. 
developing subphase) 
2.1 
D 
Only primary and cortical alveolar oocytes present. 
Developing 
2.2 
D 
Primary growth, CA, Vtgl and Vtg 2 oocytes present. 
SC* early GVM 
3.1 
HI 
Predominance of Vtg3 and early OM and beginning of GVM, yolk coalescence 
beginning. Few germinal GVBD oocytes observed, although some hydrated 
oocytes present. 
SC* GVM 
3.2 
H2 
Both early and late stages of GVM oocytes, obvious yolk coalescence occurring. 
Greater abundance of GVBD oocytes seen. Increased number of hydrated oo- 
cytes present. 
SC* GVBD 
3.3 
H3 
Predominance of GVBD oocytes, many with complete yolk coalescence. Many 
hydrated oocytes present — immediately before ovulation. 
SC recent POF 
4.1 
NA 
Many recent POFs present, showing few signs of degeneration. Otherwise ad- 
vanced oocytes consist most noticeably of Vtgl-Vgt3 oocytes. 
SC older POF 
4.2 
NA 
Only older POFs present with advanced structural degeneration. Advanced 
oocytes consist of Vtgl-Vgt3 oocytes. 
Regressing 
5.0 
S 
Only spawning residue (old POFs) and primary growth oocytes remain in the 
ovary. Spawning effort for season ceased. 
Regenerating 
6.0 
RE 
Only primary oocytes remain in small ovary. Ovarian wall thickened, muscle 
bundles present. 
(0100-0500 h, 0500-0900 h, 0900-1300 h, 1300-1700 
h, 1700-2100 h, 2100-0000 h EST) to examine diel 
periodicity in reproductive maturity (Anderson, 2011). 
Each longline was fished with 150 to 400 circle hooks 
set 2 m apart for an average soak time of 2 h. The 
number of hooks fished per line on each trip was de- 
pendent on the success of catching Haddock that day. 
With the intent of sampling at least 50 Haddock from 
each longline set, the number of hooks was increased if 
the sample size was not reached or decreased if more 
fish than were needed were caught. 
All Haddock were measured by fork length (FL, 
±1 mm) and examined externally for signs that indi- 
cated if they were in the ripe and running maturity 
stage (classified RR; Table 1). Ovaries were classified 
as RR when eggs were observed to be running freely 
from females with little pressure applied to the abdo- 
men. The first 50 Haddock in each set were sacrificed 
to determine the stage of development of the gonads. If 
a fish ovary was observed to be ripe and running, its 
sex and maturation stage could be determined with- 
out excisions, and it was automatically classified as RR 
in the field. A subsample of the 50 sacrificed female 
Haddock that represented all reproductive stages from 
each longline set was labeled and reserved on ice. Fish 
from each of the following length bins were collected 
from each set if possible to have representation from as 
many cohorts as possible: 30-40 cm, 40-50 cm, 50-60 
cm, and >60 cm FL. 
Laboratory methods 
Samples were processed in the laboratory within 24 
h of the end of each trip. Total weight (±0.1 kg) and 
ovary weight (±0.01 kg) of each individual were re- 
corded. Macroscopic maturity stage of all samples was 
re-examined by the same field examiner. Digital pho- 
tographs of whole ovaries were taken from a random 
subsample of each stage in the field index. To deter- 
mine the accuracy of macroscopic maturity staging per- 
formed with our maturation index, histological analysis 
was conducted on tissue samples of a subsample of 169 
ovaries from 1706 macroscopically classified fish repre- 
sentative of all 8 stages. 
All histological tissue samples were taken from 
the forward right lobe of each ovary. It was assumed 
that this approach was appropriate because, according 
to Robb (1982), Haddock ovaries are homogeneous in 
structure throughout both lobes with oocytes present in 
various stages from the walls to the center of the ovary. 
Samples of 10-g tissue sections were fixed for at least 
14 days in 10% neutral buffered formalin before they 
were transferred to 50% isopropyl alcohol. Samples 
were processed with standard histological procedures 
