Don’t Blame the Fish! And, don’t prescribe fish.
February 24, 2011
By Boyce Thorne Miller and Niaz Dorry
This essay is in response to: How does our food production system drive our exposure to toxic chemicals?
Consumer advisories warning the public to limit their intake
of particular fish because they contain high levels of certain chemicals are
ubiquitous. On the other hand, the medical community, nutritionists, and
government agencies in this country prescribe frequent fish consumption for Omega-3
fatty acids and other positive health factors. Lost in this sea of incongruity
is the fate of the marine animals that on one hand are being vilified as the
enemy of human health because they’ve been poisoned by human induced industrial
pollution and on the other are eaten by humans because of their health
It’s time to stop blaming or prescribing fish and ask
ourselves the following questions: what are the persistent pollutants found in
some marine animals doing to the health of the animals themselves? Could it be affecting
the cognitive, reproductive and immune systems of marine animals such as tuna?
Just like the people who eat them, could they be suffering health impacts as
they become the conduit for toxic human products and wastes back to people? What
does producing seafood for mass consumption do to the marine environment? And,
finally, what are the human health implications of industrial scale fishing and
seafood production – which is the strategy promoted by aquabusiness (agribusiness’ equivalent on the water) in order to meet
the rising tide of health agency recommendations for increased seafood consumption?
This last question should be at the forefront of our minds as human health and
marine conservation advocates.
Much of the public dialogue about toxic exposure from
seafood is centered on vilifying the fish with calls to stop eating fish like
tuna, famous for containing mercury amongst other persistent bioaccumulative
toxicants (PBTs). The more sophisticated conversation calling for a ban on the
introduction of PBTs through clean production strategies is pretty much
contained within the environmental health movement. In other words, the public
discussion is about addressing the symptoms of a widespread epidemic – toxic
chemicals in our food. The emphasis is on eating food that is presumably free
of toxins, rather than real prevention by stopping the source of pollutants in
our natural foods.
Rachel Carson best captures this epidemic when she said, “As
crude a weapon as a cave man's club, the chemical barrage has been hurled
against the fabric of life.”
Carson sounded the alarm about toxicants on behalf of the
wildlife first. But governments and regulatory agencies would not take
seriously the impact of these chemicals on the health of the fish, whale, or
bird populations. We’ve since learned that ignoring the impact of these
toxicants on the animals means ignoring the health of our own food chain. By
allowing them to be poisoned, we only continue to poison our own bodies.
We began shifting the debate in the 1980s by bringing the
focus onto human health, but in the process we forgot that wildlife are really
on the front lines of the fight against chemicals in our food. By tracing the
sources of contamination in humans, the connection between the health of
animals and humans has become clearer. In fact, we believe environmental
pollutants comprise one of the major hurdles the marine food web is facing
today. And that food web often culminates with humans.
A public outcry in opposition to toxic marine pollution and
the production and use of chemicals complicit in that is essential if we are to
protect our marine based food system. And, health advocates need to be part of
this movement if they are going to continue prescribing seafood as a remedy for
human health problems.
Cleaning up our coastal waters and restoring coastal
habitats would help bring back depleted fish populations to areas fished by
local fishing communities and would contribute to healthful local and regional
seafood markets. But coastal waters are on the receiving end of much of the
PBTs from land based sources. We hope the increased interest in adding seafood
to healthful diets will bring about actions that improve local marine habitats
for fisheries. But we are concerned that without a public outcry and support of
health professionals, the trend might shift from cleaning up our act to scouring
the global markets for fish caught or grown in poorly managed industrial
fisheries and aquaculture around the world. As a result, all too often people
are choosing farmed seafood, especially salmon, thinking they are improving
their diets and their health.
Spawning a Toxic Blue Revolution
The new drive to eat more fish has caused unfettered growth
of industrial scale fish farming, particularly salmon farming, in waters
wherever they can be grown around the world:
Chile, Norway, Scotland, Canada, and Faroe Islands most commonly, and to
a more limited extent the US and a few additional European countries. Other
popular carnivorous fish like cod and halibut are also being farmed on small
research scales but about to go commercial. And a US company is trying, with apparent
success, to put a genetically engineered salmon into farms for global marketing.
There are many things wrong with this picture. Very often
the health and survival of a diversity of wild fish are being threatened and
the human health advantages proclaimed aren’t even being realized:
- Farmed salmon has a significantly decreased
ratio of Omega-3s to Omega-6s (which have negative health impacts), due to the
diet they are fed and the stress they are under. In salmon farms, substitute
feed using terrestrial plant protein like soy meal (a current proposal) would
markedly alter the healthfulness if not the taste of the fish, and Omega-3s
would be diminished even more. Omega-3s in the fish we eat come from the food
organisms they eat (small fish and crustaceans), which in turn get it from their
food -- marine phytoplankton (microscopic plants).
- Market demand for salmon is being used by
companies to introduce genetically engineered salmon into the aquaculture
industry, with the added potential of negative health impacts from the
introduced genes. While the genes used may be from other fish species that are
safely edible, we don’t know what the impact of putting them into salmon might
be – beyond the faster growth and larger size for which they are intended. Genes
are complicated and new gene interactions may switch on other chemical
processes that are not desirable. We just don’t know.
- Since fish farms are most often located in
coastal ocean waters, they are subject to the same exposure to toxic chemicals
as wild fish. Therefore, farmed fish are equally as contaminated as wild fish,
and could be more so if they happen to be located in contaminated areas and/or
if feed is contaminated. Salmon feed may be contaminated with toxic substances
and farmed salmon are routinely treated for diseases and parasites.
Regardless of whether fish come from fishing boats or sea
farms, the more processing they undergo and the longer the distance and time they
travel once they are caught, the more the health benefits are diminished. So
fresh caught local fish may indeed be a boon to the health of local consumers,
but people who don’t have such access should be offered other foods with
similar health benefits, which just might involve redesigning local agriculture
– a concept already afoot by the local food movement.
So what should we eat from the ocean?
- Eat a
variety of seafood. After all, the ocean is a diverse ecosystem and if we
are to eat from it, our diet should reflect its diversity to the extent that it
does not undermine the integrity of the ecosystem.
- Eat low
on the marine food chain. The ocean
is a fish-eat-fish world and much of the pollutants are passed onto bigger fish
through their diet.
- Eat wild
fish. Aquaculture is riddled with practices using pesticides, hormones and
other toxic chemicals known to have adverse affects on human health.
seafood that is local to your region and still looks like what it did when it
was alive. Processing and preservation mechanisms often involve chemicals
we don’t want or need in our bodies.
And, most importantly, fight for the health of the marine
animals -- because their health is directly connected to ours.
If the health benefits of fish are to be promoted by the
medical profession and others, the prescription to eat fish should clearly be
accompanied by guidelines that are beneficial to the consumers and operate
within the capacity of the wild ocean.