From a humble mayonnaise-laden sandwich to an expensive piece of sashimi, tuna is a prized source of food for people around the world. Once an inexpensive, easily shipped canned protein source, today's bluefin tunas can fetch millions of dollars at auction. Millions of tons of tuna are harvested every year, supporting a global industry worth around US$40 billion annually. But tunas are more than just the pink flesh found in cans and sushi, and humanity's story with these fish goes back further than you might expect. As a biologist and an archaeologist interested in long-term human-environment interactions, we wanted to investigate the deep record of people's relationship with tunas. We drew on the expertise of 18 leading researchers worldwide and studied a variety of sources, from the skeletal remains of tunas in archaeological sites to ancient rock art, paintings on frescos and vases, written historical records and ethnographic accounts from…