The first program in this series illustrates the tragic effects that can result when pesticides creep into nature’s food chains. It concerns specifically the demise of a major brown pelican flock and the unnatural behavior of seals on islands off the coast of California near Santa Barbara.
This was the first episode in the series. At the time, environmental reporting on DDT was nothing new–it was, of course, the crux of Rachel Carson’s Silent Spring. But even 6 years after Silent Spring, the effects of the chemical were still not thoroughly studied.
In 1972, two years after this episode aired, the Environmental Protection Agency instituted a ban on the use of DDT for general use. The suspension of the pesticide has made a significant impact on the Channel Islands: At a time when there were only 727 annual nests in 1970, the California brown pelican nest population increased to 7,900 from 1979 to 1987 according to the Center for Biological Diversity; there were 6,000 nests as of 2004. Though the brown pelican was removed from endangered species lists on the east and southeast coasts of the U.S., only in February 2009 did The California Fish and Game Commission vote to remove it from their endangered species list.
Today the Channel Islands is populated by over 70,000 California sea lions, 50,000 northern seals, and 1,100 harbor seals. In addition to the pelicans, sea lions, and elephant seals, two of the Channel’s neighboring islands, San Miguel and Anacapa, are collectively the home of animals such as western gulls, sparrows, cormorants and black oystercatchers.
Note: The bioaccumulative effects of DDT have now been studied in more detail–but the full picture is still taking shape. DDT is still in use in many parts of the world in limited doses. This article lays some of the arguments out. Also, see this
NYTimes article revising Carson’s assertions on DDT.