PETALUMA (KCBS) – Far more whales die from ship collisions than wash up on beaches, according to a new study from a Petaluma-based nonprofit that works to protect the ecosystem and wildlife.

The report from Point Blue Conservation Science said whale deaths from ships are much higher than previously estimated, if only whales that wash ashore are counted.

“Most whales sink when they die. And so, there are a lot more that disappear without ever being counted,” said Cotton Rockwood, senior marine ecologist and the study’s lead author.

Rockwood listed ways to prevent ship collisions. “To move those lanes where possible, to avoid high-density areas of whales,” he told KCBS. “And we can also slow ships down wherever possible. That could have a huge effect decreasing the risk of strike, sometimes up to 70, 80 percent.”

There is a voluntary slowdown off the Greater Farallones National Marine Sanctuary.

Additionally, Rockwood encourages boaters use an app called Whale Alert.

“That can help us to pinpoint where and when we see whales and to report that to mariners on the sea,” he said.

In California, ship strikes of gray whales are the most commonly reported followed by fin, blue, humpback, and sperm whales.