In China, the bladder of a totoaba fish, believed to contain healing properties, is incredibly valuable — one can be sold for $40,000. When the market for bladders increased around 2012, it sparked a bonanza of overfishing for totoaba in Mexico’s Sea of Cortez. An unwitting victim of this, however, was the vaquita, a tiny, charismatic and incredibly rare porpoise endemic to the area, which drowned in totoaba nets by the hundreds. The decimation of vaquitas prompted the Mexican government to ban most forms of fishing, and what has unfolded is a complex battle between fish mafias, local fishermen and the military. So far, few winners have emerged.