Silent Springs
Rachel Carson
Michael Crawley
Anup Shah
April Quijano
Chapter 9: Rivers of Death
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The spraying of DDT and other
insecticides in ecosystems has
caused many disturbances and
problems in organisms
communities.
Rivers of Death
The Salmon and the Spruce Budworm
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In 1953, salmon returned to the
Miramichi River located in New
Brunswick, Canada, in order to deposit
eggs.
Coniferous forests of spruce and
balsam trees provide the kind of
grounds needed for salmon to survive.
Along with the hatched salmon in the
spring of 1954, salmon one or two years
old swam in the Miramichi searching for
various insects to feed on. In the
summer, it was a struggle for these fish
to find any source of food.
The watershed of the Northwest
Miramichi was included in a vast
spraying program designed to save the
forests from the spruce budworm.
The budworm is a native insect that
attacks many kinds of evergreen. It
seems to be abundant every 35 years in
Eastern Canada and there was an
upsurge in budworm populations in the
1950’s.
Rivers of Death
The Salmon and the Spruce Budworm (cont.)
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Spraying with DDT had begun in order to combat the budworm. First the spraying began
in a small way and then at an accelerated rate in 1953.
Millions of acres of forests were sprayed instead of thousands as before, in an effort to
save the balsams which are the main producer for the paper industry.
In 1954, planes were sent to spray the Northwest Miramichi with one-half pound of DDT
per acre. The pilots did not avoid the streams or turn of the spray nozzles while passing
over the areas of water.
Within two days after the spraying, dead and dying fish, including many young salmon,
were found along the banks of the stream. Brook trout also were found dead and birds
were spotted dead on roads and in the woods.
Before the spraying the stream contained caddis fly larvae, stonefly nymphs, and blackfly
larvae, which all are the diet of young salmon but all of these insects were killed due to
the DDT spraying. Therefore, the salmon had no source of food after the spraying.
The salmon born in the spring were all killed due to the insecticides. For every six young
of the 1953 hatch that had foraged in the stream, only one remained. The salmon of the
1952 hatch lost a third of their population as well.
At this time the salmon had a Type 3 survivalship curve. This meant that the salmon had
very high death rates for the young and had only a few survive.(52.1)
The DDT acted as an abiotic factor that greatly effected the flow of a food chain which
resulted in the death of the salmon.
The DDT spraying interrupted the repeated reproduction of salmon during salmon
season. (52.2)
Rivers of Death
The Salmon and the Spruce Budworm (cont.)
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The Fisheries Research Board of Canada
conducted a survey that showed more than a
loss of fish; it revealed a serious change in
the streams themselves.
The repeated sprayings completely altered
the stream environment, and the aquatic
insects that are the food of salmon and trout
had been killed.
A lot of time is needed to for most of the
insects to build up sufficient numbers to
support a normal salmon population - time
measured in years rather than months.
In order to supply natural food, Canadians
tried to transplant caddis fly larvae, but these
larvae would be destroyed if another spraying
occurred.
The budworm populations did not decrease
after the spraying and this led to sprayings
from 1955 to 1957 in New Brunswick with
some places being sprayed 3 times. By 1957,
nearly 15 million acres had been sprayed.
In 1954, a tropical storm hit Canada and
salmon were drawn in from the ocean. There
was an abundance of eggs in 1955 due to the
storm in 1954 and the young salmon were
able to live because of the number of midgies
and blackflies. Unfortunately, the older
salmon got killed off by the spraying in 1954
Rivers of Death
The Salmon and the Spruce Budworm (cont.)
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In all sprayed streams, young salmon of every size are scarce. In the main Southwest
Miramichi, which was sprayed in 1956 and 1957, the 1959 catch was the lowest in a
decade.
In 1959, the whole Miramichi watershed produced only 600,000 smolt (young salmon
descending to the sea). This was less than a third of the runs of the three preceding
years.
Rivers of Death
Spraying in the United States
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The spraying of DDT also took place in Maine in order to stop the spread of
forest insects. The spraying did not display a major hurt to the salmon of
Maine, but instead to other fish in 1958.
A study found that moribund suckers were showing signs of DDT poisoning;
they swam erratically, gasped at the surface, and exhibited tremors and
spasms.
In the first 5 days of spraying, 668 dead suckers were collected and minnows
and trout were also killed.
In 1955, Yellowstone National Park was sprayed which greatly affected the
fish population. About 90 miles of rivers were affected and in a 300 yard
length, 600 dead fish were counted, including brown trout, whitefish, and
suckers.
Even with these results, Forest Service officials stated that it was safe to
spray one pound of DDT to the acre.
Montana Fish and Wildlife Service studied the death and discovered that the
insecticide was very harmful to the fish and wildlife.
Control of the budworm had not even been achieved after all of this spraying.
Despite the precautions taken to try to help reduce risks of spraying, 100
percent of the salmon in four streams was killed.
Rivers of Death
Alternate Methods to Spraying
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There are cases on record where natural parasitism has kept the budworm under control
more efficiently than spraying.
There are possibilities of using less toxic sprays which include using microorganisms that
will cause disease among the budworms without affecting the whole web of forest life.
It is important to realize that chemical spraying of forest insects is neither the only way
nor the best way.
Rivers of Death
Pesticide Threat to Fishes
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One threat of spraying is to the fishes of running streams in northern forests
and to the single problem of forest spraying.
Another is vast, sprawling, and diffuse, for it concerns the many kinds of
fishes: bass, sunfish, crappies, suckers, and others.
Fish are most sensitive to chlorinated hydrocarbons which make up most of
the modern insecticides.
Reports of fish kills, some of disastrous proportions, have now become so
common that the United States Public Health Service has set up an office to
collect such reports from the states.
Rivers of Death
Economic Affects
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40 million Americans look to fishing as a major source of recreation and they
spend 3 billion dollars annually.
Anything that deprives them of their sport will reach out and affect a large
number of economic interests.
The commercial fisheries need fish in order to produce food. Inland and
coastal fisheries yield an estimated 3 billion bounds a year.
The spraying of pesticides is now a threat to both recreational and
commercial fishing
Rivers of Death
Destruction of Fish
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Agricultural crop sprayings are
everywhere to be found.
In California, the loss of 60,000
game fish followed an attempt to
control the rice leaf miner with
dieldrin.
In Louisiana, 30 or more instances
of heavy fish mortality occurred in
one year alone because of the use
of endrin on sugarcane fields.
The use of heptachlor in the
southern U.S. was for fire ants.
This chemical killed thousands of
fish in the south. This led to a halt
in aerial spraying.
Toxaphene was used to kill cotton
insects but ended up killing
hundred of fish due to chemicals
washed into the rivers by rain.
Rivers of Death
Destruction of Fish (cont.)
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In 1961 , Austin, Texas, was shocked to see dead fish for nearly 200
miles.
Texas Game and Fish Commission discovered that the chemicals
killing all of the fish were coming form a chemical plant.
The manager of the plant knew that they were disposing chemicals
into storm sewers and they had been doing this for the past 10 years.
27 different species of fish were observed, about 1000 pounds to a
mile of riverbank.
Florida salt marshes were sprayed with dieldrin and the results were
catastrophic. The Entomology Research Center of the State Bored
of Health stated that 1,175,000 fish died of 30 species.
Pesticides are also a threat to shrimp fisheries. The insecticide
tolerance for shrimp was found to be very low by the Bureau of
Commercial Fisheries especially at a young age.
Clams and oysters are vulnerable to pesticides too.
Chapter 10: Indiscriminately
from the Skies
People have had misgiving about aerial
sprayings because of two programs: The
gypsy moth program in Northern parts of the
United States and the Fire Ant program in the
Southern parts of the United States.
Indiscriminately from the Skies
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Gypsy Moth (cont.)
A few individuals from this species
had escaped in 1869 from a
laboratory in Massachusetts. It had
spread in the North mainly due to
wind. The Adirondacks have
served as a barrier to stop the
gypsy moths from spreading
towards the rest of the US.
The above statement is an
example of dispersal which is the
moving of individuals away from
their area of origin. (50.2)
Before the aerial spraying
programs started, 13 predators
and parasites were imported from
outside the US. Along with that and
local spraying, achieved praises
from the Department of Agriculture
in 1955.
Gypsy moths are ectoparasites
which means they feed off the
external surface of the host. (53.1)
Indiscriminately from the Skies
Gypsy Moth (cont.)
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In 1956, a program was started to eradicate the gypsy moth, despite protests
against citizens. It covered a million acres in Pennsylvania, New Jersey, and
New York. It included New York City and Long Island, two areas where gypsy
moths would not normally live (their normal habitat is forests, not fields,
marshes, and cities). Spray planes had been paid by the gallon than by acre,
and many properties were sprayed several times.
Animals and fields had been contaminated. This made it harder for farmers to
sell their farm produce since the FDA prohibits no residues in milk. Leaf crops
were also burned and spotted, which hurt truck gardeners.
After 1957, the spraying programs was curtailed, and the area sprayed had
decreased to 100 acres in 1959, 1960, and 1961. People could not sue
against the firm who handled the spraying since it was out of state, had no
local address, and did not register with state officials.
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Indiscriminately from the Skies
Fire Ant
Named for its fiery sting, it was first found in
Mobile, Alabama shortly after WWI. By 1928, it
had spread to the suburbs of Mobile and started
to invade the rest of the Southern states.
Before 1957, it was not considered a threat, but
rather as a nuisance, because of the large nests
it tends to built. Also, it was proved to be helpful
since it preyed on harmful insects.
In 1957, the Department of Agriculture launched
a propaganda program to get supporters for their
spraying program against the fire ant. The
program mainly showed the fire ant as a
dangerous insect which spoils crops and kills
living organisms.
Because of the program, wildlife in the sprayed
area became devastated. For example
opossums, armadillos, and raccoon had
disappeared in Hardin County, Texas.
Populations of the bob-white quail and wild turkey
were decimated. Woodcocks were found to have
up to 20 parts per million of heptachlor 6 months
after. A two moth calf was tested by a scientist by
Dr. Pointevint, and was found to have 79 parts
per million of heptachlor in its fat.
The above bullet is an example of biological
magnification. Toxins such as insecticides
become more concentrated in the fat tissues of
an organism in a successive tropic levels of a
food web. (54.5)
Indiscriminately from the Skies
Fire Ant (cont.)
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After three years, the rate of application went down to ¼ a pound. Also, to
offset the dissatisfaction with the program, the Agriculture Department offered
free chemicals to farmers in exchange for them taking responsibility for their
damage. Alabama had stopped funding the program, and farmers in
Louisiana gradually showed reluctance to sign up for the program.