Andres Albonigamayor stares down at the red deck of his fishing boat as the last albacore are unloaded. It¡¯s two hours before sunrise on the wharf of Bermeo, a town in Spain¡¯s Basque Country, and his crew of six Senegalese men work in silence as wind whistles through the metal walls of an empty warehouse nearby. There was a time when the wharf buzzed with activity before the 7 a.m. auction, but the port hasn¡¯t been crammed with boats in years.

The 68-year-old captain shows no emotion as the fish go in auction for a decent price. He¡¯s the last of a long dynasty of Bermean fishermen, and all he cares about is the next catch. ¡°I want to go out tomorrow again,¡± he says, marking the words with the distinct pronunciation of native Basque speakers, a language so old no one¡¯s figured out when it originated. ¡°I might not even go home this time. I might just take a quick nap on the boat.¡±

Albonigamayor doesn¡¯t know it, but he¡¯s crucial in the fight against climate change. Every time he goes out to sea, he brings back the lowest-carbon animal protein available anywhere. Preserved in oil and put in cans and jars in factories just a mile away, his catch of longfin tuna becomes an unsung fix for a warming planet ¡ª a meal that¡¯s cheap, requires no energy for refrigeration, almost never spoils, and, with some effort, can be harvested sustainably.