Six U.S. fishing vessel owners have been fined hundreds of thousands of dollars for violating rules protecting tuna and marine mammals.

The National Oceanic and Atmospheric Administration said last week American Triumph Fishing has been fined more than $560,000 for using a fish aggregating device that attracts fish when rules prohibited their use. The company’s ship also set a net too close to a fish aggregating device.

Ocean Conquest, Sea Quest. Sea Honor, Ocean Encounter and Pacific Ranger were fined more than $950,000 for setting a purse seine net in the presence of whales and near a fish aggregating device.

Purse seines are giant nets used to surround and capture schools of tuna and other fish.

No whales were reported hurt by the net.

The violations occurred in the Pacific.