Changes with age in total brain concentrations of biogenic amine neurotransmitters in coho salmon (Oncorhynchus kisutch Walbaum)

Whole brain content of several biogenic amines was determined in two age groups of coho salmon (Oncorhynchus kisutch Walbaum). Brains of presmolt salmon (about 5 months old) were compared to brains of homeward migrants (4 years old). Levels of dopamine and serotonin were significantly higher in the homeward migrants.