Table 1.

Classification of gonadal samples based on histology

Sex type	Index	Gonadal maturation stage	Histological criterion	Number of samples
Female	F1	Pre-vitellogenesis	Mostly pre-vitellogenic oocytes	4
	F3	Vitellogenesis	Vitellogenic oocytes more than half of section	7
	F4	Atretic	Presence of atretic oocytes	6
Male	M1	Testis gonia	Mostly gonia	3
	M2	Spermatogenesis	Mostly spermatocytes and spermatids	2
	M3	Spermiation	Mostly spermatozoa	6
	M4	Post-spawning	Absence of spermatozoa in testicular lobules	2
		Total number of samples		30