Cosco Busan: Effects of Oil on Wildlife Resources

Note: Primary effects are sudden and/or highly visible. Secondary/sub lethal effects are more subtle and less likely to be detected in the early days of an oil spill incident. Tertiary effects will be noted only after a substantial period of time. See discussion, over.

LETHAL/PRIMARY:

  • In seabirds, feather fouling, with ensuing hypothermia from loss of insulation, inability to fly, drowning, inability to escape from predators. In sea otters and fur seals, similar hypothermia issues exist.
  • Respiratory problems from inhalation of fumes.
  • Toxicity from ingestion of oil from preening/grooming activities

SUB LETHAL/SECONDARY:

  • reduced reproductive success
  • physiological impairment
  • increased vulnerability to stress
  • infection
  • reductions in longevity or fitness due to behavioral, metabolic or genetic aberrations
  • transfer of oil from prey to predator, or from parents to young during breeding season
  • changes in food availability or predation pressure due to the effects of oil on the populations of other species.

SUB LETHAL/TERTIARY:

Tertiary effects result, in turn, from the manifestation of secondary effects (e.g. decrease in attention to offspring by oiled parents, resulting in starvation, predation of chicks, etc.)

Effects of Oil on Sea Birds also may apply to other wildlife

Many oil spills have resulted in the death of a large number of sea birds, which very sensitive to both internal and external affects of crude oil and its refined products.

Sea birds have a high risk of contact to spilled oil due to the amount of time they spend on or near the surface of the sea and on oil affected foreshores. Sea birds may also come in contact with spilled oil while searching for food, since several species of fish are able to survive beneath floating oil. (4)

Oil-coated birds can suffer hypothermia, dehydration, drowning and starvation, and become easy prey.

Sea birds (and other types of wildlife) are affected by oil in several ways:

  • Contact with crude oil or refined fuel oils. This causes feathers (or fur) to collapse and matt and change the insulation properties of feathers and down.
  • Matting of feathers. This can severely hamper the ability of birds to fly.
  • A breakdown in the water proofing and thermal insulation provided by the feathers (or fur). This often causes hypothermia.
  • Oiled feathers. This can cause the seabirds to lose buoyancy, sink and drown because of increased weight or lack of air trapped in the feathers.
  • Body weight decreases quickly as the metabolism attempts to counteract low body temperature.
  • Severe irritation of the skin.
  • They ingest the oil in an attempt to preen themselves.
  • Irritation or ulceration of the eyes, skin, mouth, or nasal cavities.
  • The food searching instincts such as diving and swimming are inhibited.
  • Ingestion of oil via their prey if their food chain becomes contaminated.
  • Poisoning or intoxication.

Ingestion of oil can be sub-lethal or acute and will depend to a large extent on the type of oil, its weathering stage and inherent toxicity. These internal effects can include:

  • the destruction of red blood cells, important for the immune response,
  • alterations of liver metabolism,
  • adrenal tissue damage,
  • pneumonia, intestinal damage,
  • reduced reproduction ability, reduction in the number of eggs laid, decreased fertility of eggs, decreased shell thickness and disruption of the normal breeding and incubating behaviors.

It has been estimated that as little as four microlitres of petroleum contaminating a fertile egg can cause the embryo to die. (2)

LINKS & SOURCES:
http://response.restoration.noaa.gov (1)
http://www.amsa.gov.au/Marine_Environment_Protection/National_Plan/General_Information/Oiled_Wildlife/Oil_Spill_Effects_on_Wildlife_and_Non-Avian_Marine_Life.asp (2)

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