100 
Fishery Bulletin 1 1 1 (1) 
Table 5 
The final female reproductive maturity index developed from findings with the macroscopic and microscopic method for 
staging the maturity of female Haddock ( Melanogrammus aegleftnus). 
,t jv.ii ^ Sij 
Immature (I) 
Macroscopic: The ovary is small and firm, and approximately 1/8 the volume of the body 
cavity. The membrane is thin, transparent, and gray to pink in color. Individual oocytes 
are not visible to the naked eye. 
*Note: This stage can look similar to a resting-stage ovary. Use of microscopic analysis 
or histology on a tissue sample of the ovary may be the only way to determine that the 
ovary is immature and not resting. 
Microscopic: The ovary contains germ cells, oogonia, and primary oocytes. The ovary 
wall is thin and the primary oocytes vary little in diameter. No muscle bundles can be 
seen. The nucleus is relatively large with the most advanced oocytes having peripheral 
nucleoli (magnification lOOx). 
Developing (D) 
Macroscopic: The ovary is plump and approximately 1/3 to 1/2 the volume of the body 
cavity. The membrane is reddish-yellow and has numerous blood vessels. The contents 
are visible to the naked eye and consist of opaque eggs, giving the ovaries a granular 
appearance. 
*Note: If hydrated oocytes are visible, the ovary should be classified as HI (see the next 
stage below). Hydrated oocytes will be large in diameter and translucent in color. A large 
tissue sample should be taken from all ovaries macroscopically classified as developing 
and analyzed microscopically to confirm that postovulatory follicles are not present and 
that the ovaries are in a prespawning state. It may be helpful to document the tissue 
sample with a photograph of the whole ovary. 
Microscopic: Primary and cortical alveoli oocytes, and primary and secondary vitellogenic 
oocytes are present. There is no evidence of postovulatory follicles (magnification 40x). 
in the field as S, 58% (N= 7) were classified as being in 
1 of the 3 OM histological phases. The most plausible 
explanation for this result, other than observational er- 
ror, is that these particular specimens were maturing 
the last batch of eggs to be spawned that season (last 
spawn) and the ovary at this point had lost its rigid- 
ness and, therefore, looked as though it was in the S 
stage. Last spawn was observed in 8 (5%) of the his- 
tological samples, 5 of which were classified as S in 
the field. Last spawn also was observed in Haddock in 
the North Sea (Alekseyeva and Tormosova, 1979). Near 
the end of the spawning season, the ovary can lose its 
rigidness, although it still has 1-2 batches of oocytes to 
spawn and appears as S. The outside membrane thick- 
ens, which increases the difficulty of staging the ovary 
through examination of just the outside (Templeman et 
ah, 1978). Staging on the basis of the flabbiness of the 
ovary alone is not recommended, and the inside of the 
ovary should be examined for hydrated oocytes. If any 
oocytes during final oocyte maturation (OM) remain, 
the ovary is most likely not in the S stage and could 
be in last spawn. Histological examination of a sample 
of an ovary can be an effective way to determine if an 
ovary is regressing. 
