We don't have synonyms for sea trout yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are seatrout, sea scout and sea front.
(n) :
A fish of the species Salmo trutta morpha trutta, closely related to salmon and a subspecies of brown trout. It is lighter in colour than the brown trout, and lives in salt water, returning to fresh water only to spawn.
(n) :
A fish of the species Salmo trutta morpha trutta, closely related to salmon and a subspecies of brown trout. It is lighter in colour than the brown trout, and lives in salt water, returning to fresh water only to spawn.