Abbreviation: Oog. Oogonia, PG. Primary growth oocyte, Nu. Nucleoli, F.e. Follicular envelope, Lo. Ovarian lumen, VtgI. Primary vitellogenic oocyte, N. Nucleus, Cyt.h. Heterogeneous cytoplasm, St. Ovarian stroma. Ow. Ovarian wall, Spg. Spermatogonia, L.l. Lobular lumen, Cyst. Cyst, Mb.l. The basal membrane of the lobule, Spcy. Spermatocyt, Spd. Spermatid, Spz. Spermatozoa. Histological sections through the gonads of P. blennoides showing different development phases (scale: 100 μm). a. General view of immature female (Gx10, caught 30/04/15, TL: 53.1 cm; WG: 3.86 g, GSI: 0.396). b. Developing female (Gx40, caught 21/12/15, TL: 27.3 cm; WG: 0.12 g, GSI: 0.601). c. Early maturing female with initial stage of vitellogensis and yolk protein (Gx40, caught 29/06/15, TL: 45.1 cm, WG: 3.9 g, GSI: 0.601). d. Histological section through the gonad of the biggest female sampled (Gx10, caught 23/04/2016, TL: 62.7 cm, WG :10.54 g, GSI: 0.61). Thick ovarian wall (Gx4) in regenerating ovaries. e. Immature male with spermatogonia cells (Gx40, caught 10/02/15, TL: 23.6 cm, WG: 0.02 g, GSI: 0.024). f. Male regenerating stage with the appearance of spermatids and spermatozoa (Gx40, caught 26/08/14, TL: 26.1cm, WG: 0.72 g, GSI: 0.373). g. Developing testes (Gx40, caught 6/01/15, TL: 21.1cm, WG: 0.5 g, GSI: 0.990). h. Mature testes with emission of spermatozoa (Gx10, caught 06/01/2015, TL: 24.1 cm, WG: 1.23 g, GSI: 2.13).