More than 1,000 dolphins and 16 minke whales were spotted by passengers and crews sailing between Cornwall and the Isles of Scilly this summer.
The sightings from the Isles of Scilly Steamship Company Scillonian III ferry were recorded as part of the Marine Biodiversity Project.
The project has become an annual event with wildlife experts.
Cornwall Wildlife Trust said dolphin sightings this summer exceeded last year's count by almost 500.
In 2009, 13 minke whales were spotted and 458 common dolphins.