Cyanobacterial Neurotoxin BMAA and Mercury in Sharks

Toxins (Basel). 2016 Aug 16;8(8):238. doi: 10.3390/toxins8080238.


Sharks have greater risk for bioaccumulation of marine toxins and mercury (Hg), because they are long-lived predators. Shark fins and cartilage also contain β-N-methylamino-l-alanine (BMAA), a ubiquitous cyanobacterial toxin linked to neurodegenerative diseases. Today, a significant number of shark species have found their way onto the International Union for Conservation of Nature (IUCN) Red List of Threatened Species. Many species of large sharks are threatened with extinction due in part to the growing high demand for shark fin soup and, to a lesser extent, for shark meat and cartilage products. Recent studies suggest that the consumption of shark parts may be a route to human exposure of marine toxins. Here, we investigated BMAA and Hg concentrations in fins and muscles sampled in ten species of sharks from the South Atlantic and Pacific Oceans. BMAA was detected in all shark species with only seven of the 55 samples analyzed testing below the limit of detection of the assay. Hg concentrations measured in fins and muscle samples from the 10 species ranged from 0.05 to 13.23 ng/mg. These analytical test results suggest restricting human consumption of shark meat and fins due to the high frequency and co-occurrence of two synergistic environmental neurotoxic compounds.

Keywords: ">l-alanine; conservation; cyanobacteria; methylmercury; neurodegenerative disease; neurotoxin; sharks; total mercury; β-N-methylamino-.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acids, Diamino / adverse effects
  • Amino Acids, Diamino / analysis*
  • Animal Fins / metabolism
  • Animals
  • Body Burden
  • Chromatography, High Pressure Liquid
  • Chromatography, Liquid
  • Food Contamination*
  • Humans
  • Methylmercury Compounds / adverse effects
  • Methylmercury Compounds / analysis*
  • Muscles / metabolism
  • Risk Assessment
  • Seafood* / adverse effects
  • Seafood* / classification
  • Sharks / classification
  • Sharks / metabolism*
  • Spectrometry, Fluorescence
  • Tandem Mass Spectrometry
  • Water Pollutants, Chemical / adverse effects
  • Water Pollutants, Chemical / analysis*


  • Amino Acids, Diamino
  • Methylmercury Compounds
  • Water Pollutants, Chemical
  • beta-N-methylamino-L-alanine