Silent Springs Rachel Carson

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Silent SpringsRachel Carson

• Michael Crawley
• Anup Shah
• April Quijano

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Chapter 9 Rivers of Death

• The spraying of DDT and other insecticides in
  ecosystems has caused many disturbances and
  problems in organisms communities.

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Rivers of DeathThe Salmon and the Spruce Budworm

• 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 1950s.

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Rivers of DeathThe Salmon and the Spruce Budworm
(cont.)

• 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)

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Rivers of DeathThe Salmon and the Spruce Budworm
(cont.)

• 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

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Rivers of DeathThe Salmon and the Spruce Budworm
(cont.)

• 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.

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Rivers of DeathSpraying in the United States

• 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.

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Rivers of DeathAlternate Methods to Spraying

• 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.

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Rivers of DeathPesticide Threat to Fishes

• 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.

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Rivers of DeathEconomic Affects

• 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

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Rivers of DeathDestruction of Fish

• 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.

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Rivers of DeathDestruction of Fish (cont.)

• 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.

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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.

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Indiscriminately from the Skies 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)
  

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Indiscriminately from the Skies Gypsy Moth
(cont.)

• 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 SkiesFire 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)

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Indiscriminately from the SkiesFire Ant (cont.)

• 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.