Oil spills affect wildlife and their habitats in many ways. The severity of the impact depends on the type and quantity of oil spilled, the season and weather, the type of shoreline, and the type of waves and tidal energy in the area of the spill.
 
If the weather is rough, the oil will disperse further but impact on more areas, also hampering clean up operations. If the weather is calm, then oil will be concentrated into a smaller area but will be more toxic and persistent in nature if not fully cleaned up.
 
Oil causes harm to wildlife through physical contact, ingestion, inhalation and absorption. Floating oil can contaminate plankton, which includes algae, fish eggs, and the larvae of various invertebrates.
 
Fish that feed on these organisms can subsequently become contaminated.
 
Larger animals in the food chain, including bigger fish, birds, mammals, and humans may then consume contaminated organisms.
 
Initially, oil has the greatest impacts on species that utilize the water surface, such as birds, dolphins, turtles, dugongs and species that inhabit the near-shore environment.

Although oil causes immediate effects throughout the entire spill site, it is the external effects of oil on larger wildlife species that are often immediately apparent.
 
The persistent part of the oil, which does not evaporate, can cause the greatest long term damage as it can be absorbed by some invertebrates, such as shellfish, and seep into sand, silt and seagrass beds.

Bunker oil can persist many years in the environment. Once the volatile parts of the oil evaporate, a sticky, thick sludge remains.