High Concentrations of Neurotoxins Found in Shark Fins

Written by on February 25, 2012 in Marine Life

Emily Tripp
Senior Writer

Sharks are among the most threatened marine species in the world due to unsustainable fishing practices.  They are killed primarily for their fins that are used in the Asian delicacy, shark fin soup.

A new study by University of Miami (UM) scientists, published in the journal Marine Drugs, has discovered high concentrations of BMAAin shark fins.  BMAA is a neurotoxin linked to neurodegenerative diseases in humans like Alzheimer’s and Lou Gehrig Disease (ALS).  So not only do shark fins have little nutritional value, but the study suggests that consumption of shark fin soup and cartilage pills may pose a significant health risk for degenerative brain diseases.

NOAA agent counting confiscated shark fins.  Photo credit: NOAA.

NOAA agent counting confiscated shark fins. Photo credit: NOAA.

“Shark fins are primarily derived through finning, a practice where by shark fins are removed at sea and the rest of the mutilated animal is thrown back in the water to die,” said co-author Dr. Neil Hammerschlag, research assistant professor of Marine Affairs & Policy and director of the RJ Dunlap Marine Conservation Program (RJD) at UM.  “Estimates suggest that fins from as many as 70 million sharks end up in soup.  As a result, many shark species are on the road to extinction.  Because sharks play important roles in maintaining balance in the oceans, not only is shark fin soup injurious to the marine environment, but our study suggests that it is likely harmful to the people who are consuming them.”

Blacknose, blacktip, bonnethead, bull, great hammerhead, lemon, and nurse sharks were tested for this study.  Samples were collected from live animals in waters around South Florida.

“The concentrations of BMAA in the samples are a cause for concern, not only in shark fin soup, but also in dietary supplements and other forms ingested by humans, “ says study co-author Professor Deborah Mash, Director of the University of Miami Brain Endowment Bank.  The Bank supports basic and clinical research and holds one of the world’s largest collection of postmortem human brains, covering a wide range of neurological disorders.  In 2009, Professor Mash and her co-authors published a study demonstrating that patients dying with diagnoses of Alzheimer’s Disease and ALS had unusually high levels of BMAA in their brains of up to 256 ng/mg.  Normal, healthy aged people have no BMAA, or only trace quantities.

The range of BMAA in shark fins exceeded this quantity, with levels from 144 to 1836 ng/mg.

“Not only does this work provide important information on one probable route of human exposure to BMAA, it may lead to a lowering of the demand for shark fin soup and consumption of shark products, which will aid ocean conservation efforts,” added Hammerschlag.

Copyright © 2012 by Marine Science Today, a publication of OceanLines LLC.

About the Author

About the Author: Emily Tripp is the Publisher and Editor of MarineScienceToday.com. She holds marine science and biology degrees from the University of Miami's Rosenstiel School of Marine and Atmospheric Science and a Master of Advanced Studies degree in Marine Biodiversity and Conservation from Scripps Institution of Oceanography. When she's not writing about marine science, she's probably running around outside or playing with her dog. .

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