SafetyIssues Personal and Public Safety News Articles: Having Shark Fin Soup or Clam Chowder?  

Having Shark Fin Soup or Clam Chowder?
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Staff Writer on 10/10/07 05:25:00
 
The intentional hunting of sharks, primarily for shark fin soup, appears to have
drastically reduced shellfish populations such that clam chowder, the American
soup favorite, has disappeared from the menu of many East Coast restaurants.
As strange as that may seem, the biological equation is quite clear. When shark
numbers are high, they feed on species such as skates and rays – which eat
bivalves, like clams and oysters. Fewer sharks mean more skates and rays which
means fewer shellfish.
The published research of a world-renowned fisheries biologist at Dalhousie
University, Ransom Myers, who died early this year, showed that shark hunting
along with unintentional shark deaths when they get caught in trawler nets,
resulted in 98 percent declines in populations of tiger sharks, hammerhead
sharks and blacktip sharks along the East Coast.
The decline in shark numbers led to the dramatic increase in species they prey
upon, particularly cownose rays. Legions of cownose rays along with other skate
and ray species have wiped out bay scallops, clams, and maybe, soon, oysters.
In the Chesapeake Bay area, the large cownose ray population could now consume
840,000 metric tons (nearly 2 billion pounds) of bivalves annually.
Fishermen along the coast of Virginia and Maryland landed only 300 tons (around
661,380 pounds) of bivalves in 2003. This catch is much lower than the
historical average catch for the area.
Researchers at the University of St. Andrews, Scotland, fear that the demand for
shark fin soup has threatened the economically important bivalve fisheries and
also resulted in an ecological and culinary bankruptcy.
Perhaps those who hanker for shark fin soup should also be aware of something
about sharks: they can be full of dangerous pollutants. Sharks are at the top of
the food chain, and contaminants eaten by smaller animals down the chain become
concentrated in shark bodies.
In another recent study by researchers at Stockholm University, the team found
that Greenland sharks, which live in the most sparsely populated regions on
Earth, contain high concentrations of man-made industrial wastes. The main
source of these wastes – polychlorinated biphenyls, or PCB – has been banned
for over 30 years.
These findings thus demonstrate the longevity of these dangerous compounds in
the environment and how top predators may carry these substances around in their
bodies for decades. Greenland sharks have a normal lifespan above 100 years.
The 10 female shark samples studied were accidentally caught and killed in trawl
fisheries near Iceland.
The highest concentration found was for the world’s most toxic dioxin, TCDD, a
chemical found in Agent Orange herbicide used by the US military during the
Vietnam War. The herbicide was also used for other purposes from 1961 to 1971.
The second highest concentration was for a furan, TCDF, which is a byproduct of
combustion from power plants, incineration of garbage and other industrial
processes.
Safety Tip: Avoid having shark fin soup. This will spare you from pollutants
and, hopefully, it will help bring clam chowder back.