Pick over and flake the smoked trout fillets.

Drain plain yogurt in a fine sieve for 1 hour.

Mince fresh dill and onion.

Pat the minced onion dry.

In a food processor, combine the flaked trout, drained yogurt, mayonnaise, lemon juice, minced dill, and minced onion.

Add salt and pepper to taste.

Puree the mixture until smooth.

Refrigerate the trout mixture covered for up to 1 day.

Cut the pumpernickel bread into decorative 2-inch shapes.

Spread a scant teaspoon of the trout mixture on each bread piece, mounding it.

Garnish each canapé with a dill sprig.