Melamine fed to fish

From ANIMAL PEOPLE, June 2007:
VANCOUVER–The potential for global ecological disaster as
result of cheating in international trade was illustrated on May 8,
2007, when the Vancouver-based Canadian division of Skretting
International recalled fish food sold to 25 Oregon Department of Fish
and Wildlife hatcheries because it contained melamine.
As melamine is water-soluable, it does not accumulate in the
bodies of fish, unlike heavy metals such as mercury and chemical
compounds, such as PCBs.
“We do not believe this poses any significant human health
threat,” said FDA food safety chief David Acheson.
But melamine itself was not the cause for worry. The greater
concern was what if the contaminant had been more volatile,
longer-persisting, or biologically active?

Skretting International, founded in 1899, sells fish food
to hatcheries and aquaculture operations from Norway to Chile. Many
Skretting customers raise fish in sea pens, from which a disease or
contaminant could spread to the wild.
This time the problem was detected because the entire animal
feed industry was on alert as result of pet food recalls that started
on March 16, 2007.
If the contaminant had not sickened thousands of pets, whose
vigilant caretakers alerted veterinarians and food manufacturers,
factory farmers of fish, chickens, and pigs might not have been
aware of anything wrong, because those animals are typically
slaughtered before health effects that are passed through food chains
can become apparent.
Melamine was reportedly found only in a Skretting starter
feed prepared for juvenile salmon and trout. As the fish grow, they
are switched to a different feed formula.
In addition, the tainted material from which the feed as
made was apparently used only at the Vancouver plant, not throughout
the Skretting chain.
The melamine pet food contamination saga spread to Canada on
April 10, when pet food suspected of making animals ill was traced
to the Menu Foods packaging plant in Streetsville, Ontario, almost
a month after recalls of food packed in two U.S. plants started.
The Agriculture and Food Laboratory at the University of
Guelph in Ontario achieved a breakthrough in investigating the issue
about a week later, finding that
cyanuric acid, found in urine samples from poisoned animals,
interacts with melamine to form crystals that appear to block kidney
function.
Only about 1% of the melamine-contaminated wheat and rice
gluten that is believed to have been sold to animal food
manufacturers is known to have gone to Canada.