A fisherman reported raw sewage had been dumped into Frederick Sound near Le Conte Bay on the morning of July 10, but the cruise ship Le Soléal's captain, Erwan Le Rouzic, said any sewage found in the bay could not have been from them.

"This cannot be us," wrote Le Rouzic in a statement to Dave Berg of Viking Travel. "It is impossible. We are strictly following the most stringent rules in Alaska waters."

Berg first contacted Le Rouzic after some fishermen noticed a presence of "long brown sludge" north of the ship's anchorage after its departure from Le Conte Bay last week. In a letter to the...