PH25 Wildlife Ecotoxicology II
Exhibit Hall
8:00 AM - Thursday
(PH294) Contaminants in lesser scaup (Aythya affinis) from the Yukon Flats National Wildlife Refuge, Alaska, USA.
Rocque, D1, Matz, A2, 1 U.S. Fish and Wildlife Service, Anchorage, AK, US2 U.S. Fish and Wildlife Service, Fairbanks, AK, US
ABSTRACT- Lesser scaup (Aythya affinis) are the most abundant North American diving duck, but has become a species of concern following years of declining populations. The Yukon Flats region in Alaska contains the greatest density of nesting lesser scaup in North America, and changes in this breeding population are an important indicator of overall population trends. Yukon Flats breeding populations of lesser scaup have declined approximately 34% over the last 20 years. Many factors contributing to low reproductive success, such as predation, drought, and habitat degradation (including contaminants) play a role in lesser scaup population declines. Most contaminants in lesser scaup are thought to be accumulated on the wintering grounds in and around industrialized areas. However, the extent to which many of these contaminants persist in tissues or are excreted through egg laying is currently unknown. Contaminant concentrations in lesser scaup blood and eggs from the relatively pristine Yukon Flats National Wildlife Refuge were evaluated to determine whether contaminant concentrations were of concern. All trace elements and organochlorine concentrations were considered relatively low. Lesser scaup accumulate selenium in some wintering areas such as the Great Lakes, making concentrations in eggs a particular interest for assessing whether selenium accumulated on wintering areas depurates during migration in northern breeding populations. Egg selenium concentrations (0.9 ug/g dw) were below background levels and may indicate that selenium accumulated on wintering grounds is excreted or metabolized during migration and is not a factor in reproductive health of this breeding population. Lead levels in blood were low and did not indicate exposure above background levels. These data provide reference contaminant concentrations for a widespread duck species, and indicate that contamination does not presently appear to be a factor in declining lesser scaup populations breeding in interior Alaska.
Key words: lesser scaup, Alaska, eggs, blood