Salmon do use magnetic senses to navigate the oceans as well, but it is an acute sense of smell (among other things) that allows (most of) them to return to the headwaters of their birth.

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idunnoman1222 2 years ago | parent [-]

None of those salmon were born there because the Damn was in the way

	▲	shkkmo 2 years ago \| parent \| next [-]
		Water flows downstream. The water the Salmon were born is smells substantially the same as the water that is from up river, that chemical content will change as tributaries enter the river but you'll probably see greater variations between forks than between spots of the same river.
	▲	jimnotgym 2 years ago \| parent \| prev \| next [-]
		They were born in the lower part of the river, below the dam. They just followed it up a bit!
	▲	2 years ago \| parent \| prev [-]
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