Tuna Fishery Traps Dolphins, Birds and Sharks

Fishing for tuna in the eastern North Atlantic took a heavy toll on marine animals during the 1990s.

The commercial fishery trapped and tossed overboard cetaceans, seabirds, reptiles and fish. Drift nets aimed at albacore tuna killed over 24,000 dolphins, mainly common and striped dolphins.

Birds discarded from tuna drift nets include northern gannets, northern fulmars, manx shearwaters and Atlantic puffins. Even leatherback turtles fell victim to the fishing gear.

Blue sharks showed up most often in the bycatch that decade, with at least 780,000 becoming trapped in the nets. Although seldom fished commercially, blue sharks have declined noticeably in the Atlantic as so many are inadvertently caught. The sharks made up two-thirds of the fish discarded from the eastern North Atlantic albacore tuna fishery.

These findings on tuna bycatch casualties come from observations made onboard fishing vessels during 1996 and 1998. Researchers at University College in Cork, Ireland who analyzed the records conclude that besides the tuna, "a large biomass of megafauna" was removed.