productivity in western Prince William Sound, where oil remained, was nearly zero during 1989- 

 1993; reproduction was substantial in un-oiled portions of eastern Prince William Sound (Patten 

 1994). Petrochemicals were found in the proventriculus, liver and bile in Harlequins in western 

 Prince William Sound and southwestern Kodiak Island; these were probably introduced via 

 feeding on blue mussels {Mytilus adulis), an important food of Hariequins (Patten 1994). A 

 relatively small oil spill in 1991 by the TenyuMaru threatened approximately 10% of the 

 Harlequins wintering in Washington (G. Schirato pers. comm. /// Clarkson 1994). Even the 

 remote western Aleutian Islands, where most Harlequin winter, sparse , but wide-spread oil 

 pollution is a potential threat (Byrd et al. 1992). 



Wintering Harlequins concentrate in several areas along the Pacific coast for feeding and molt. 

 Among these concentration areas are the east shore of Vancouver Island where toxic pollutants 

 are abundant (Waldichuk 1983 in Clarkson 1994). and commercial, industrial, and recreational 

 development are growing rapidly. 

 Degradation of habitat: breeding and wintering. 



Breeding. In 1992 a gas pipeline project was started, crossing the Moyie River in Idaho 8 

 times (Cassirer 1995). Harlequins are known to use this stream and a study was begun when 

 siltation was noted from construction. The siltation caused a decline in macroinvertebrates fed on 

 by Harlequins, and there no young were successfully raised the year the construction took place 

 (Cassirer 1995). Recovery of macroinvertebrates was expected to occur within a year and 

 Harlequins successfully bred the following year. The effects of the construction could have been 

 minimized by doing the work in late summer (after 1 September) or fall. The long term effect of 

 the loss of one years production on the very small population present is not known (Cassirer 

 1995). However, several items were noted, including the fact that Harlequins attempted to breed 

 (unsuccessfully) despite the disturbance, and did not move to nearby streams. 



MANAGEMENT 

 Federal 



Fish and WildUfe Service. Neither the Atlantic or Pacific populations are listed as 

 Threatened or Endangered in the United States. The Harlequin Duck was listed as a Category 2 

 Candidate Species prior to 1996 when that Category was administratively eliminated. It is legally 

 hunted in the Pacific states and provinces under the Migratory Bird Treaty Act and state, 

 provincial and federal regulations. Hunting is closed on the Atlantic flyway. 



National Park Service. A seasonal boating closure was instituted on McDonald Creek 

 above Lake McDonald in Glacier National Park in 1995 to protect Harlequin Ducks; the stream is 

 closed to boating from 1 April though 30 September (J. Ashley pers. comm). No boating on 

 rivers is allowed in Yellowstone National Park to protect wildlife values. No U.S. National Park 

 Service Harlequin Duck management plan exists. 



Forest Service. The Harlequin Duck is a Sensitive Species in the Northern, Rocky Mountain, 

 and Pacific Northwest Regions. Forest Service policy states that sensitive species should be 

 managed to ensure that populations do not become threatened or endangered. 



States/Heritage Programs. The Harlequin Duck is classified as a state sensitive species in 

 Oregon, a priority habitat species in Washington, and a species of special concern in Idaho and 

 Montana. 



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