Every year, 3,500 big ships come into the Bay Area, where some say it's time to look for ways to make the ocean quieter.
"Up on land we rely on our eyes to see, but in the ocean, a darkened environment, it's all about sound," Jackie Dragon, of Greenpeace, said.
Whales need sound for just about every part of their lives -- from finding food to caring for their young. But it's getting harder for whales to hear.
Dragon and is part of a working group of government, industry and environmental organizations studying ocean noise and whales.
"With so many ships in the ocean coming and going, it's created a tremendous amount of noise and it's a particular noise in that same frequency range that is utilized by baleen whales, those are the whales we have in San Francisco and off the coast of California, humpbacks, greys, blues, fins, many of which are highly endangered," Dragon said.
ABC7 went along with Dragon on a San Francisco whale watching tour boat to listen to the shipping noise first hand. In the Gulf of Farallones Sanctuary, a protected area outside the Golden Gate, whales are often spotted. A major shipping lane runs right through the sanctuary.
An underwater microphone picks up the sound of a nearby container ship.
"When we have the sounds of ships such as this, which we have thousands of coming in and out of our busy ports, its flooding this ocean world with this constant fog of noise," Dragon said.
No one knows for sure if or how that noise has contributed to the recent wave of ships hitting whales. But a biologist with the International Fund for Animal Welfare says there's plenty of evidence noise is interfering with whale behavior.
"A lot of people think underwater -- out of site, out of mind, but in reality noise under water should be regulated just like pollution is on land," Jacob Levenson asid.
A spokesperson for the shipping industry says they need more research, but they are open to change.
"As a matter of fact, at the international level they are already discussing ways to modify the propeller design and other things, perhaps engine noise," Pacific Merchant Shipping Association spokesperson John Berge said.
Some environmental groups are also petitioning the federal government to create speed limits for big ships. That could cut noise and give whales more time to get out of the way.
The Coast Guard just issued a recommendation to change some of the shipping lanes into San Francisco Bay but they did not propose a speed limit.
Written and produced by Jennifer Olney