Trout and Salmon ID Quiz Answer: Atlantic Salmon

We held a quiz last week to test your fish identification skills. The fish pictured here is Salmo salar, better known as the Atlantic salmon.

The Atlantic salmon is often called the “leaper” or the “king of fish” because it is capable of making astounding jumps as it performs its migratory spawning ritual, often clearing natural waterfalls and obstacles (like this) that would stop other fish in their tracks. (They’re also extremely tough, acrobatic fighters for fly anglers to tangle with).

The Atlantic salmon is the genetic cousin of the brown trout (or sea trout), Salmo trutta. Both are members of the family Salmonidae, but there are subtle differences — which is exactly why fish ID skills are important to learn. Whacking a rare Atlantic salmon by mistaking it for a brown trout can land you in trouble in certain places. New Hampshire Fish & Game produced this quick guide to differentiate the two.

In short, the main differences are that the caudal (tail) fin of the salmon may be slightly forked, while the brown trout’s is not, and the caudal peduncle (that body part above the tail) is slim on the salmon but stocky on the brown. The best indicator is that the adipose fin of a brown trout may be red or orange tinted, while that is never the case with Atlantic salmon.

The winner(s) of our quiz are fliphuntr14, who gave good detail, and colbytroutbum, who got the length exactly right.

For the record, this fish was caught in Russia on the Ponoi. I would have accepted “grilse” as well. You can tell this fish had wintered in the river by its darker coloring and size. The fresh-from-the-sea salmon are chrome bright.

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