Effect of gender and reproductive status on brain catecholamine and indoleamine levels of flagfish (Jordanella floridae)

Levels of serotonin, 5-hydroxyindoleacetic acid, tryptophan, noradrenalin and dopamine were determined in whole brains of male (dominant, subordinate, solitary and resting) and female (laying and resting) flagfish (Jordanella floridae) and related to reproductive activity. Levels of serotonin were consistently elevated in sexually active male flagfish, relative to resting males. Dominant males exhibited lower noradrenalin levels than all other groups of fish. Solitary males exhibited higher levels of noradrenalin than dominant males, and were not significantly different from resting males. The lowest levels of tryptophan were apparent in brains of sexually inactive males and females. Neither sex nor reproductive status had a significant impact on 5-hydroxyindoleacetic acid levels. The hatchability of eggs fertilized by solitary males was reduced by over 40% when compared to dominant males.