Moving or traveling in an opposite or backward direction, particularly describing migratory fish that swim upstream.
From anti- (against) + -dromous (from Greek drómos, 'running'). Biological term for organisms moving counter to typical migration.
Salmon are antidromous in a sense—they're driven to swim upstream against the current to spawn, which is so exhausting that it kills them after spawning, making it an extreme investment.
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