 It entered the oceanic food web, contaminating and accumulating in several species, including one of the pelican's primary food fish – the northern anchovy.Its metabolite DDE is a reproductive toxicant in pelicans and many other birds, causing eggshell thinning and weakening, and consequent breeding failure through the eggs being accidentally crushed by brooding birds.Since an effective ban on the use of DDT was implemented in the US in 1972, the eggshells of breeding brown pelicans there have thickened and their populations have largely recovered.