| Dear
EarthTalk: Are the animals used in classroom
dissection taken from the wild? If so, wouldn't this be endangering
their populations? Are there other environmental issues associated
with classroom dissection? -- William Conway, via e-mail
According
to the Humane Society of the United States (HSUS), most animals
used in dissection--including amphibians, birds, snakes, turtles,
fish and invertebrates--are taken from the wild, even though
many have been declining in population. Smithsonian Institution
researchers who surveyed 14 major dissection supply catalogs
found only one that offered “farm-raised” amphibians;
none of the others verified their sources.
Researchers from the World Conservation Union reported in
2004 that a third of all amphibian species around the globe,
including frogs, were threatened with extinction. Although
habitat loss, pollution and climate changes are the primary
causes, demand for dissection specimens only makes matters
worse. Analysts estimate that as six million wild frogs are
destroyed each year in the U.S. alone for dissection.
Taking frogs from the wild also increases insect populations,
including those that carry disease. Frogs eat more than their
weight in bugs every day. Farmers the world over have long
relied on frogs to keep crops pest-free, but a lack of frogs
in recent years has led many farmers to switch to pesticides.
Concerns about this prompted India to ban frog sales in 1987.
India had been earning $10 million yearly on frog exports,
but was spending $100 million importing insecticides, according
to the group Mercy for Animals.
The use of formaldehyde in preserving animal specimens is
also a concern. Classified by the U.S. Environmental Protection
Agency as a “hazardous air pollutant, water pollutant
and waste constituent,” formaldehyde can cause nausea,
headaches and breathing difficulties in people, and has been
linked to cancer in animal studies. Teachers and students
involved in frequent dissections are exposed to it regularly.
Further, schools discard millions of formaldehyde-laden classroom
specimens each year, raising questions about its effects on
the larger ecosystem as well.
Animal advocacy groups and some educators also question dissection
on both practical and ethical grounds. While it is intended
to interest students in science, they say, it may be having
an opposite affect while also encouraging cruelty to animals
outside class. According to the Physicians Committee for Responsible
Medicine (PCRM), a 1997 study of seventh graders found that
fetal pig dissections fostered callousness toward animals
and dissuaded students from pursuing science careers. PCRM
also cites surveys where as many as 90 percent of students
said they should be able to opt out of dissection.
A number of computer-based teaching tools now on the market
provide alternatives to live animal dissection. Digital Frog
International’s award-winning “Digital Frog 2”
allows a student to “dissect” a computer-generated
frog with a digital scalpel. The non-profit TeachKind provides
a comprehensive online listing of such resources. Nine U.S.
states--Florida, California, Pennsylvania, New York, Rhode
Island, Illinois, Virginia, Oregon and New Jersey--now have
laws that allow students to beg out of cutting animals and
to use such alternatives. Other states have implemented policies
that serve a similar purpose.
CONTACTS: HSUS, hsus.org/animals_in_research/animals_in_education;
PCRM, www.dissectionalternatives.org;
TeachKind, www.teachkind.org/dissectalt.asp.
PHOTO
COURTESY OF GETTY IMAGES
Analysts
estimate that, each year in the U.S. alone, six million wild
frogs are captured and destroyed for classroom dissection.
Dear EarthTalk:
What are the pros and cons of marine aquaculture, of raising
ocean fish instead of catching them in the wild? -- Jeanne
L., Norwalk, CT
Marine aquaculture, an age-old practice in parts of Asia,
has grown in popularity in western countries in recent years
in response to dwindling supplies of wild fish in the world’s
oceans. According to the Pew Oceans Commission, a blue-ribbon
panel of fisheries and marine biology experts, high-tech fishing
practices, such as drift netting, have led to a potentially
irreversible decline in populations of key seafood species.
Some shark, tuna and cod species have declined as much as
90 percent in the past few decades.
Most marine biologists agree that, as human population continues
to grow worldwide, there will not be enough wild-captured
fish to meet demands for seafood. Aquaculture, “the
propagation and rearing of aquatic organisms in controlled
or selected environments,” as defined by the U.S. National
Oceanic and Atmospheric Administration (NOAA), is seen by
many as the best way to fill the gap. Currently aquaculture
supplies about 30 percent of the world’s seafood, up
from just four percent 30 years ago.
James McVey of NOAA’s Sea Grant program says aquaculture
can reduce the need for seafood imports and provide jobs for
coastal communities. “The U.S. currently brings in $10
billion in seafood from other countries,” he says. “With
increased production capacity, our higher yields from aquaculture
will bring down this trade deficit, and improve food security--where
we’re not as reliant on other nations for food.”
But aquaculture’s down sides give many scientists pause.
Studies indicate that, despite the promise of reducing pressures
on wild fish, aquaculture requires two pounds of wild-caught
fish to use as feed to make one pound of farmed fish. Further,
says SeaWeb, breeding farms--where thousands of fish, and
their waste, are concentrated--breed diseases that can then
escape and contaminate wild fish populations.
To control such outbreaks, many fish farmers treat their stocks
with antibiotics that can also make their way into the oceans
and wreak havoc. The farmed fish themselves also escape from
their pens and interbreed with and take over habitat traditionally
occupied by wild populations. Another major problem with aquaculture,
according to SeaWeb, is its destruction of natural habitats.
The group blames shrimp farming, for example, for destroying
coastal mangrove forests in the Philippines, Thailand and
elsewhere.
But many scientists do feel that aquaculture has the potential
for helping the world’s marine ecosystems rebound--if
it is done conscientiously. Among other things, SeaWeb recommends
that fish farmers avoid using drugs to fight disease and that
governments do more to regulate and police aquaculture operations
to make sure otherwise pristine waters are not fouled and
sensitive coastal ecosystems are not damaged.
According to the Monterey Bay Aquarium’s “Seafood
Watch” program, the greatest power to end irresponsible
aquaculture rests with consumers. The organization’s
website offers tips on which kinds of farmed seafood to buy
and which to avoid. While no one person’s choices will
improve the environment dramatically, collectively consumers
can play a role in how producers treat the ecosystems they
utilize.
CONTACTS: NOAA, www.nmfs.noaa.gov/mediacenter/aquaculture/;
SeaWeb’s “Ocean Briefings: Marine Aquaculture,”
www.seaweb.org/resources/briefings/aquaculture.php;
Monterey Bay Aquarium’s Seafood Watch Regional Seafood
Guides, www.mbayaq.org/cr/SeafoodWatch/web/sfw_regional.aspx.
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