DOI: 10.5061/dryad.m9t12
title: Data from: Wintering sea duck distribution along the Atlantic coast of the United States

description: Although monitoring data for sea ducks (Tribe Mergini) are limited,
 current evidence suggests that four of the most common species wintering
 along the eastern coast of the United States—long-tailed duck Clangula
 hyemalis, white-winged scoter Melanitta fusca, surf scoter Melanitta
 perspicillata, and black scoter Melanitta americana—may be declining,
 while the status of American common eider Somateria mollissima dresseri is
 uncertain. The apparent negative trends, combined with the fact that sea
 duck life histories are among the most poorly documented of North American
 waterfowl, have led to concerns for these species and questions about the
 impacts of human activities, such as hunting, as well as catastrophic
 events and environmental change. During winter, thousands of sea ducks are
 found along the U.S. Atlantic coast, where they may be affected by
 proposed wind-power development, changes to marine traffic, aquaculture
 practices, sand mining, and other coastal development. Possible impacts
 are difficult to quantify because traditional winter waterfowl surveys do
 not cover many of the marine habitats used by sea ducks. Thus, the U.S.
 Fish and Wildlife Service conducted an experimental survey of sea ducks
 from 2008 to 2011 to characterize their winter distributions along the
 U.S. Atlantic coast. Each year, data were collected on 11 species of sea
 ducks on &gt;200 transects, stretching from Maine to Florida. In this
 paper, we describe distribution of common eider, long-tailed duck,
 white-winged scoter, surf scoter, and black scoter. Densities of the two
 species with the most northerly distribution, white-winged scoter and
 common eider, were highest near Cape Cod and Nantucket. Long-tailed duck
 was most abundant around Cape Cod, Nantucket Shoals, and in Chesapeake
 Bay. Surf scoter also concentrated within Chesapeake Bay; however, they
 were additionally found in high densities in Delaware Bay, and along the
 Maryland–Delaware outer coast. Black scoter, the most widely distributed
 species, occurred at high densities along the South Carolina coast and the
 mouth of Chesapeake Bay. Spatial patterns of high-density transects were
 consistent among years for all species except black scoter, which
 exhibited the most interannual variation in distribution. The distance
 from land, depth, and bottom slope where flocks were observed varied among
 species and regions, with a median distance of 3.8 km from land along the
 coastal transects and 75% of flocks observed over depths of &lt;16 m.
 Common eider and long-tailed duck were observed closer to shore and over
 steeper ocean bottoms than were the three scoter species. Our results
 represent the first large-scale quantitative description of winter sea
 duck distribution along the U.S. Atlantic coast, and should guide the
 development of sea duck monitoring programs and aid the assessment of
 potential impacts of ongoing and proposed offshore development.
description: DataACWSDsurvey.zipData S1. All data for the analyses are contained in the zipped folder titled DataACWSDsurvey.zip. The file contains three comma delimited data files, CluterWeightsMatrix.csv, ObservationData.csv, and TransectInformation.csv, as well as a ReadMe text file describing all data fields for each data file.Caithamer_et_al_2000_Sea_Ducks_in_the_Atlantic_FlywayReference S1. Caithamer DF, Otto M, Padding PI, Sauer JR, and Haas GH. 2000. Sea ducks in the Atlantic flyway: population status and a review of special hunting seasons. Laurel, Maryland: U.S. Fish and Wildlife Service.National_Ocean_Council_2011_Draft_National_Ocean_PolicyReference S2. National Ocean Council. 2011. Draft National Ocean Policy Implementation Plan. 115 pp.Sea_Duck_Joint_Venture_2003_Special_Status_ReportReference S3. Sea Duck Joint Venture. 2003. Species status report. Continental Technical Team.Sea_Duck_Joint_Venture_2007_Recommendations_for_monitoringReference S4. Sea Duck Joint Venture. 2007. Recommendations for monitoring distribution, abundance, and trends for North American sea ducks.Sea_Duck_Joint_Venture_2012_Atlantic_and_Great_Lakes_Migration_Study_Progress_ReportReference S5. Sea Duck Joint Venture. 2012. Atlantic and Great Lakes Migration Study Progress Report - March 2012.Sea_Duck_Joint_Venture_2008_Strategic_PlanReference S6. Sea Duck Joint Venture Management Board. 2008. Sea Duck Joint Venture Strategic Plan 2008 - 2012. Anchorage, Alaska and Sackville, New Brunswick.Silverman_et_al_2010_Annual_Survey_Report_for_2009Reference S7. Silverman E, Koneff M, Fleming K, and Wortham J. 2010. 2009 Atlantic coast wintering sea duck survey. Laurel, Maryland: U.S. Fish and Wildlife Service.Silverman_et_al_2011_Annual_Survey_Report_for_2010Reference S8. Silverman E, Koneff M, Fleming K, and Wortham J. 2011. 2010 Atlantic coast wintering sea duck survey. Laurel, Maryland: U.S. Fish and Wildlife Service.Silverman_et_al_2012a_Annual_Survey_Report_for_2011Reference S9. Silverman E, Leirness J, Saalfeld D, and Richkus K. 2012a. 2011 Atlantic coast wintering sea duck survey. Laurel, Maryland: U.S. Fish and Wildlife Service.Silverman_et_al_2012b_Atlantic coast wintering sea duck survey 2008-11 ReportReference S10. Silverman ED, Leirness JB, Saalfeld DT, Koneff MD, and Richkus, KD. 2012b. Atlantic coast wintering sea duck survey, 2008 – 2011. Laurel, Maryland: U.S. Fish and Wildlife Service.