EarthTalk: What are the differences between
farmed versus wild salmon when it comes to human and environmental
-- Greg Diamond, Nashville, TN
advocates would like to end fish farming and instead
put resources into reviving wild fish populations.
Pictured: a salmon farming operation in Chile.
© Sam Beebe, EcoTrust
farming, which involves raising salmon in containers placed
under water near shore, began in Norway about 50 years ago
and has since caught on in the U.S., Ireland, Canada, Chile
and the United Kingdom. Due to the large decline in wild
fish from overfishing, many experts see the farming of salmon
and other fish as the future of the industry. On the flip
side, many marine biologists and ocean advocates fear such
a future, citing serious health and ecological implications
with so-called “aquaculture.”
Mateljan, founder of Health Valley Foods, says that farmed
fish are “far inferior” to their wild counterparts.
“Despite being much fattier, farmed fish provide less
usable beneficial omega 3 fats than wild fish,” he
says. Indeed, U.S. Department of Agriculture research bears
out that the fat content of farmed salmon is 30-35 percent
by weight while wild salmons’ fat content is some
20 percent lower, though with a protein content about 20
percent higher. And farm-raised fish contain higher amounts
of pro-inflammatory omega 6 fats instead of the preponderance
of healthier omega 3s found in wild fish.
to the feedlot conditions of aquafarming, farm-raised fish
are doused with antibiotics and exposed to more concentrated
pesticides than their wild kin,” reports Mateljan.
He adds that farmed salmon are given a salmon-colored dye
in their feed “without which their flesh would be
an unappetizing grey color.”
aquaculture proponents claim that fish farming eases pressure
on wild fish populations, but most ocean advocates disagree.
To wit, one National Academy of Sciences study found that
sea lice from fish farming operations killed up to 95 percent
of juvenile wild salmon migrating past them. And two other
studies—one in western Canada and the other in England—found
that farmed salmon accumulate more cancer-causing PCBs and
dioxins than wild salmon due to pesticides circulating in
the ocean that get absorbed by the sardines, anchovies and
other fish that are ground up as feed for the fish farms.
A recent survey of U.S. grocery stores found that farmed
salmon typically contains 16 times the PCBs found in wild
salmon; other studies in Canada, Ireland and Great Britain
reached similar conclusions.
problem with fish farms is the liberal use of drugs and
antibiotics to control bacterial outbreaks and parasites.
These primarily synthetic chemicals spread out into marine
ecosystems just from drifting in the water column as well
as from fish feces. In addition, millions of farmed fish
escape fish farms every year around the world and mix into
wild populations, spreading contaminants and disease accordingly.
advocates would like to end fish farming and instead put
resources into reviving wild fish populations. But given
the size of the industry, improving conditions would be
a start. Noted Canadian environmentalist David Suzuki says
that aquaculture operations could use fully enclosed systems
that trap waste and do not allow farmed fish to escape into
the wild ocean. As for what consumers can do, Suzuki recommends
buying only wild-caught salmon and other fish. Whole Foods
and other natural foods and high end grocers, as well as
concerned restaurants, will stock wild salmon from Alaska
Valley Foods; USDA;
EarthTalk: I’ve been hearing about the
great gas mileage for Volkswagens that use diesel fuel.
But is it better for the environment to use diesel or unleaded
-- K. Cronk, Bay City, MI
the past, diesel fuel was always considered dirtier
than gasoline. But newer standards regulating sulfur
content and improved technology in diesel engines
have made diesel somewhat kinder to the environment.
Pictured: a 2009 Volkswagen Jetta TDI Clean Diesel.
© Chris Luckhardt, courtesy Flickr
In the past,
diesel fuel was always considered dirtier than gasoline.
But newer standards regulating sulfur content and improved
technology in diesel engines have made diesel somewhat kinder
to the environment. Many eco-advocates now tout diesel as
a viable and preferable alternative to regular unleaded
fuel really shines over gasoline is improved fuel economy
thanks to its higher “energy density”: Diesel
contains more power per liter than gasoline. Today’s
diesel engines have 20-40 percent better fuel economy than
their gasoline counterparts, which some say more than makes
up for the fact that they also produce about 15 percent
more greenhouse gases. This greater efficiency means that
diesel engines emit less carbon monoxide and carbon dioxide
and fewer hydrocarbons than gasoline engines.
downside is that it emits larger amounts of nitrogen compounds
and particulate matter (soot) that can cause respiratory
problems and even cancer. The California Air Resources Board
(CARB) attributes 70 percent of that state’s cancer
risk from airborne toxins to soot from diesel cars and trucks.
Nationwide, studies have shown a 26 percent mortality increase
for those living in soot-polluted areas.
dark side is getting a little brighter, thanks to new technologies
such as Mercedes-Benz’ BlueTEC system (now used in
many VW, Audi and Chrysler diesel models) that filters particulates
while improving overall engine performance. The Diesel Technology
Forum (DTF), a trade association of carmakers, engine builders
and petroleum distributors, reports that technologies now
commonplace in new diesel engines reduce the tailpipe output
of particulate matter by as much as 90 percent and nitrogen
oxides by some 50 percent compared to diesel engines on
the road just a decade ago.
has made significant strides in recent years to develop
diesel systems that are cleaner and more efficient than
ever before,” reports DTF. “Thanks to state-of-the-art
engines, cleaner-burning fuels, effective emissions-control
systems, and advancements in the fuel injection system,
it would take 60 trucks sold today to equal the soot emissions
of one 1988 truck.” U.S. Environmental Protection
Agency (EPA) data shows that airborne diesel particulate
levels fell by more than 37 percent during the 1990s.
improving fuel efficiency standards in the European Union
(where the majority of new cars purchased in many member
countries use diesel fuel) are forcing carmakers to design
more fuel efficient, less polluting vehicles around the
world. After all, there’s no sense in designing better
engines for one region with high standards and another for
areas with less stringent rules. Another green benefit of
diesel-powered engines is their ability to run on plant-derived
biodiesel instead of petroleum-based diesel. And in the
near future consumers may be able to shop for new diesel-electric
hybrid cars now on the drawing boards of major automakers
around the world. For now, consumers looking to buy a new
or used car—diesel or otherwise—can see how
different models stack up in regard to efficiency and emissions
via the FuelEconomy.gov website, a joint effort of the EPA
and the U.S. Department of Energy.
Technology Forum; FuelEconomy.gov.