Environmental group Greenpeace has slammed Korean fishermen for over-fishing tuna species, endangering other marine animals in the process.

“Korean pelagic fishing boats are over-hunting tuna with Fish Aggregating Devices (FADs), damaging marine life including dolphins, many of which are captured along with tuna,” according to a report released by Greenpeace in Seoul Sunday.

FADs, which consists of floats secured to the ocean floor by concrete blocks, are mostly used by tuna fishing boats to attract marine species such as tuna and the common dolphinfish.

Other species such as sharks, sea turtles and dolphins could be trapped in what Greenpeace described as “death traps” and are “collateral damage” in the hunt for tuna.

Korea became the second-biggest tuna fishing country capturing a total of 311,925 tons, coming next to Japan with 497,979 tons, reports Korea JoongAng Daily.

But Japanese fishermen do not use FADs in hunting tuna, an official in the tuna industry told JoongAng Ilbo.

Japanese fishermen generally hunt bluefin and yellowfin tuna for sashimi and sushi, while Korean fishing boats hunt skipjack tuna, which are commonly sold canned.

Although members of the Western and Central Pacific Fisheries Commission agreed last December to expand the season for not using FADs from three months to four months every year, Korean companies have yet to follow the regulation.