The diets of modern and historic bottlenose dolphin populations reflected through stable isotopes

The delta(13)C and delta(15)N compositions of teeth used in combination wit h existing data provide dietary information for different populations of we stern North Atlantic bottlenose dolphins (Tursiops truncatus.). The dental isotopic signatures of bottlenose dolphins collected during the 1980s signi ficantly differ for coastal and offshore ecotypes and are consistent with r eports that coastal forms feed primarily on fish whereas offshore individua ls consume more squid. In a second study, the isotopic compositions of teet h from bottlenose dolphins that span a 100-yr period and data from publishe d stomach content analyses as well as field observations made during the pa st 100 yr provide evidence that coastal bottlenose dolphins from the 1880s, 1920s, and 1980s had similar diets.