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Effects of Oil Spills on the Survival Rate of Ducks

Oil spills adversely affect wildlife by causing immediate death, eliminating potential food sources and interfering with physiological processes for extended periods. Many populations of species do not recover for long periods of time, if at all, due to residual oil deposits lingering for years after such incidents. Marine duck populations are especially affected due to their reliance on feeding from near-shore waters, where most oil pollution collects.

  1. Duck Populations and the Exxon Valdez

    • In 1989, the Exxon Valdez ruptured and spilled oil into the waters of Prince William Sound, Alaska. Immediately after the incident, up to 25 percent of the harlequin duck population was killed, according to a report in the October 2010 issue of "Ecological Applications." Since the time of the spill, the authors reported survival rates decreased for an additional six to nine years in various areas. The study states, due to immigration of other birds from outside of the area, the recovery of the population should be within 24 years. The study concluded the effects of such a disaster last much longer than previously assumed.

    Survival Rates of Marine Ducks

    • After an oil spill, marine ducks are captured and treated in veterinary hospitals until fully recovered from injuries sustained directly from oil spills or from injuries due to capture. A report in the September 2001 issue of "The Canadian Veterinary Journal" investigated the frequency of successful treatment of seaducks after such an incident involving the tanker Erika in December 1999. The study found 65 percent of the captured ducks, surviving the oil spill, were completely healed and more than 40 percent were released back into the wild.

    Loss of Feeding Habitat

    • The April 2000 issue of "The Condor" included an article examining the effects of the Exxon Valdez oil spill on marine bird populations. The authors analyzed populations of birds, including harlequin ducks, over several periods. The study found populations continued to be less than pre-spill numbers throughout 1998. The authors concluded that birds that dive for their food continued to be the most effected by the oil spill, probably caused by oil remaining in the environment even after a decade since the accident.

    Genetic Changes and Reproduction

    • A study appearing in the May 2000 issue of the "Marine Pollution Bulletin" examined genetic changes in harlequin ducks following the Exxon Valdez incident. The study found a steroidogenic enzyme, P450-1A, responsible for the induction of sex hormones, was increased in the liver of duck inhabiting areas affected by oil contamination. Due to the manipulation of these hormones and consequent reproductive capabilities, the authors concluded the oil spill inhibited the recovery of the harlequin duck population by interfering with their breeding cycles.

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