https://motherboard.vice.com/en_us/article/nekkmx/endangered-atlantic-bluefin-tuna-tamed-sushi-ieo

The atmosphere in the new tuna-rearing facility in the small coastal town of Mazzaron, in southeastern Spain, is dead calm. It has to be. About 100 young Atlantic bluefin tuna, each about the size of a football, are adapting to life in a 22-by-10 meter tank. If spooked, they can burst straight into the wall, shattering their own spines.

Bluefin born in captivity die this way by the millions in their larval stage, but collisions grow less common as they age. Still, on the morning I visit the massive bluefin tanks at the Centro Oceanografico de Murcia, this is exactly what has happened to a one-year-old juvenile: face-first into concrete, dead on impact. “This is the first one to die in three months,” Dr Fernando de la Gandara, the center’s director, reassures me in a hushed tone.