Sharks are among the most threatened of marine species worldwide due to unsustainable overfishing. They are primarily killed for their fins to fuel the growing demand for shark fin soup, which is an Asia delicacy. A new study by University of Miami (UM) scientists in the journal Marine Drugs has discovered high concentrations of BMAA in shark fins, a neurotoxin linked to neurodegenerative diseases in humans including Alzheimer's and Lou Gehrig Disease (ALS).