Postsmolt change in numbers of acetylcholinesterase-positive cells in the pineal organ of the Pacific coho salmon
We have examined the occurrence of acetylcholinesterase (AChE)-positive cells in the pineal organ of different developmental stages of the Pacific coho salmon. Large numbers of AChE cells were present in fresh-water living alevins, in all stages of presmolts (n=307-544), and in adult spawners (n=696-1774) whereas seawater-living postmolts displayed a total lack of labeled cells. The AChE-reactive
