U.S. consumers sued Bumble Bee, Chicken of the Sea and StarKist, accusing the country's three major packaged-tuna brands of deceiving them into thinking their tuna is caught only through "dolphin-safe" fishing practices.

The proposed class actions filed on Monday said the defendants employ fishing techniques that kill or harm dolphins, and do not always use safer, costlier pole-and-line and other methods used by such rivals as Whole Foods and Trader Joe's.

The consumers said this makes the defendants' dolphin-safe labels false and misleading, violating the laws of several U.S. states including California, Florida, New Jersey and New York.

They also said StarKist violated federal racketeering law through its alleged dealings with foreign fishing companies.

Concern about dolphin safety "makes tuna fish consumers no different from Hindus attributing zero value to beef products, or vegans attributing zero value to animal products, or vegetarians attributing zero value to meat, fish, and poultry," the complaints said.

StarKist said it does not discuss pending litigation, but would not buy tuna "caught in association with dolphins." It also condemned "indiscriminate fishing methods" that trap dolphins along with the intended catch.

Bumble Bee did not immediately respond on Tuesday to requests for comment. Chicken of the Sea had no immediate comment.

The lawsuits filed with the U.S. District Court in San Francisco seek full refunds for consumers nationwide who bought tuna in the last four years, or for premiums paid for the dolphin-safe claims.

It was not immediately clear how the consumers plan to show the claims were misleading. Their law firm did not immediately respond on Tuesday to requests for comment.

The complaints said the defendants have made dolphin-safe claims since 1990, when the federal Dolphin Protection Consumer Information Act banned false labeling of tuna products.

In December, the World Trade Organization said U.S. laws governing dolphin-safe labels complied with that group's rules.

Bumble Bee is controlled by private equity firm Lion Capital, Chicken of the Sea by Thailand's Thai Union Group PCL, and StarKist by South Korea's Dongwon Industries Co.