Figure 2. Distribution of monoamines noradrenaline (NA), dopamine (DA) and serotonin (5-HT) at the different stages in the sexual cycle of Perna perna at the Moroccan sites of Bouknadel, Mohammedia and Hay El Fath.

Quantitative analyses were performed on the gonads, pedal ganglia and the cerebroid ganglia. The different stages (St0 + IIID; StI + II; StIIIA and egg-laying) correspond to an approximation of the % of mussels entered into the sexual stages based on the histological analysis obtained in another cohort collected at the same time (respectively July and September 2010 and March and April 2011). The data correspond to the mean ± sem of 8 independent measurements, each sample containing 5 individuals for each organ considered. Variation between sites; *p < 0.05, **p < 0.01, ***p < 0.001 is expressed with respect to the content measured from Bouknadel; +p < 0.05, ++p < 0.01, +++p < 0.001 to report difference between the content measured at Mohammadia and Hay El Fath (PLSD test).