Oiled Wildlife Care Network

Photo: oiled turtle
Oiled loggerhead turtle during the Deepwater Horizon spill in the Gulf Coast, 2010.

Effects of Oil on Wildlife

Oil spills can have disastrous consequences for wildlife that depend upon the ocean for survival. No matter how much is spilled, oil in the environment always puts animals at risk.  Seabirds and marine mammals are two groups of animals that are most commonly cared for during an oil spill response. Birds and marine mammals such as sea otters and fur seals rely on their feathers or fur to form a waterproof, insulating barrier around their bodies. Oil exposure disrupts this barrier and the animal becomes cold and loses buoyancy in the water. The animal’s ability to swim or fly, find food, and escape predators is impaired.  Beyond these primary effects of oiling, exposure can cause severe damage to the internal organs such as the lung, stomach, intestine, liver, kidney, and reproductive system. 

Factors that affect the severity of the damage caused by an oil spill and the success of an oiled wildlife response include: type of oil spilled, time of year and weather patterns, location of the spill, and species affected. 

  • Oil Type: Petroleum products range from viscous, heavy bunker fuel oils and tars to light, volatile products such as diesel and jet fuel. The lighter products frequently cause significant burns, eye irritation, neurological signs, and lung damage from inhalation of fumes. However, these products evaporate from the surface of the water quickly. Heavier products (such as crude oil) are less caustic but may also cause physiological problems when ingested or absorbed through the skin. These products persist much longer in the environment. It is important to note that even non-toxic oils, such as vegetable oil and fish oil, can be extremely damaging to wildlife because they affect the physical structure of feathers and fur, causing a loss of waterproofing similar to petroleum oils.
  • Time of Year: The timing of an oil spill and the weather conditions have a great impact upon the severity of the effects of a spill.  Winter weather may hamper cleanup and recovery efforts, and cause oiled animals to lose body heat more rapidly. An oil spill during a breeding season may have severe impacts upon the reproductive success of adults and the survival of young animals. 
  • Location of the Spill: Rapid recovery of oiled animals is essential to their survival. The chances of survival decrease the longer an affected animal is cold and living without access to food and water.  Oil spills in remote areas where affected animals cannot be safely accessed can have disastrous consequences for wildlife. The OWCN maintains trained personnel and active facilities throughout the state of California to ensure that animals are recovered and receive care as quickly as possible.  
  • Species Affected: The rehabilitation process can be a stressful and challenging experience for a wild animal. Some species of animals are extraordinarily resilient and respond extremely well to rehabilitative care. Measures to reduce the stress of captivity and return the animal to its natural environment as quickly as possible are essential to the successful care of oil-affected animals.