Summary of Sea Duck Disease Studies in Dutch Harbor: A 

Case for Restoration in Unalaska Bay 

March 21 , 2008 

Kimberly Trust, U.S. Fish and Wildlife Service 

Tuula Hollmen, Alaska SeaLife Center Paul 

Flint, Alaska Science Center 

Background: In 2004. USGS, USFWS and the Alaska Sea Life Center CASLC) were 

investigating the exposure of two near-shore species, harlequin ducks (HADU) and Steller's 

eiders (STEI) to petroleum hydrocarbons from industrial and non-industrial areas around Dutch 

Harbor. As part of that study, we also collected movement data on both of these species using 

standard radio telemetry techniques. Several of the birds carrying transmitters died, and four 

carcasses (3 STEI and I HADU) were recovered and sent to the Alaska Sea Life Center (ASLC) 

for necropsy. 

The dead ducks had low body weight and tested positive for microbial organisms, including E. coli. 

E.coiL a bacteria usually found in the intestinal tract of vertebrates was found in skin tissue at the 

transmitter site (on the outside of the body cavity). In an ancillary study, birds captured from Dutch 

Harbor were transported live to the ASLC. Many ofthese birds arrived at the facility with oral lesions 

and other signs of illness. E. coli cultured from one of these birds was found in the air sac. an organ 

not typically associated with this bacteria. Researchers familiar with avian diseases determined that 

such a high prevalence of obviously ill individuals from a single wild bird population was of concern, 

and studies were initiated to identify pathogens found in these birds and the extent to which they were 

exposed. 

In a current study, the following objectives are being investigated: 

• We are using molecular typing to characterize duck and water -borne organisms and to compare 

strains and track transmission ofE. coli a) between ducks and water and b) among ducks 

We are evaluating the pathogenicity otE. coli to ducks using field data by comparing bacterial 

culture results with a panel of health indicators from each bird. 

Results to Date: From 2005-2007, fecal and oral swab samples were collected from HADU and 

STEI around Dutch Harbor and from a "clean" control site, Izembek Lagoon. Birds were screened 

for a variety of pathogens. including bacteria. viruses and parasites. Water samples were also 

collected and screened for coliforms and viruses. 

The results for the E. coli analyses are the most complete to date. Samples from I 17 STEI and 

21 HADU from Dutch Harbor were cultured for bacteria. In 2004 and 2007, 20 and 27 

samples, respectively were collected from STEI in Izembek lagoon as reference samples. No 

HADU samples were collected from Izembek. Overall, 16% of the STEI and 67% ofthe 

HADU from Dutch Harbor were found positive for E.coli. In 2005, no STEI from lzembek 

tested positive for E. coli and only one bird was positive in 2007. 
In DNA tests, avian pathogenic E. coli was identified in STEI and HADU. This type ofE. coli 

is associated with disease in birds. In two HADU, DNA tests identified additional types ofE. 

coli: enterotoxigenic and enterohemorhaggic. These E. coli are associated with disease in 

mammals and are likely mammalian in origin. Additionally, coli forms, including E. coli, 

were found in water samples collected ITom Unalaska Bay. and an E. coli from a water 

sample was found to match an E. coli isolated from a duck. Based on the large number of 

known existing individual E. coli subtypes (-50,000) and the odds against finding a match 

between the water and an individual duck, it is extremely unlikely that the birds were 

exposed to these bacteria away from the site. 

Other disease results are pending.