Aquatic Synthesis for Voyageurs National Park Information and Technology Report USGS/BRD/ITR—2003-0001 U.S. Department of the Interior U.S. Geological Survey Technical Report Series The Biological Resources Division publishes scientific and technical articles and reports resulting from the research performed by our scientists and partners. These articles appear in professional journals around the world. Reports are published in two report series: Biological Science Reports and Information and Technology Reports. Series Descriptions Biological Science Reports ISSN 1081-292X Information and Technology Reports ISSN 1081-2911 This series records the significant findings resulting These reports are intended for publication of book- from sponsored and co-sponsored research programs. length monographs; synthesis documents; compilations They may include extensive data or theoretical analyses. of conference and workshop papers; important planning Papers in this series are held to the same peer-review and and reference materials such as strategic plans, standard high-quality standards as their journal counterparts. operating procedures, protocols, handbooks, and manuals; and data compilations such as tables and bibliographies. Papers in this series are held to the same peer-review and high-quality standards as their journal counterparts. Copies of this publication are available from the National Technical Information Service, 5285 Port Royal Road, Springfield, Virginia 22161 (1-800-553-6847 or 703-487-4650). Copies also are available to registered users from the Defense Technical Information Center, Attn.: Help Desk, 8725 Kingman Road, Suite 0944, Fort Belvoir, Virginia 22060-6218 (1-800-225-3842 or 703-767-9050). An electronic version of this report is available on-line at: <http://www.cerc.usgs.gov/pubs/center/pdfdocs/ITR2003-0001.pdf> Front cover: Aerial photo looking east over Namakan Lake, Voyageurs National Park. Aquatic Synthesis for Voyageurs National Park Information and Technology Report USGS/BRD/ITR—2003-0001 May 2003 by Larry W. Kallemeyn1 , Kerry L. Holmberg2, Jim A. Perry2, and Beth Y. Odde2 Prepared in cooperation with: National Park Service, Voyageurs National Park 3131 Highway 53 International Falls, MN 56649 1USGS, Columbia Environmental Research Center, International Falls Biological Station, 3131 Highway 53, International Falls, MN 56649 2College of Natural Resources, University of Minnesota, 1530 N. Cleveland Avenue, St. Paul, MN 55108 Suggested Citation: Kallemeyn, L.W., Holmberg, K.L., Perry, J.A., and Odde, B.Y., 2003, Aquatic Synthesis for Voyageurs National Park: U.S. Geological Survey, Information and Technology Report 2003-0001, 95 p. Contents Page Executive Summary......................................................................................................................................................vi Defining the System.......................................................................................................................................................1 Drainage Basin Characterization....................................................................................................................................2 Climate.............................................................................................................................................................2 Geology............................................................................................................................................................3 Hydrology........................................................................................................................................................7 Regulated Lake Levels....................................................................................................................................9 Lake Morphometry and Drainage Area Characteristics................................................................................13 Future Needs and Opportunities......................................................................................................15 Physical, Chemical, and Trophic State Observations....................................................................................15 Temperature, dissolved oxygen, and light.......................................................................................16 Water chemistry...............................................................................................................................18 Interior Lakes....................................................................................................................20 Water Quality Criteria.......................................................................................................21 Sensitivity to Acid Precipitation.......................................................................................23 Trophic status..................................................................................................................................27 Future Needs and Opportunities......................................................................................................28 Biological Communities...............................................................................................................................................28 Phytoplankton...……………………………………………………………………….................................28 Future Needs and Opportunities......................................................................................................30 Zooplankton...................................................................................................................................................30 Future Needs and Opportunities......................................................................................................33 Zoobenthos.....................................................................................................................................................34 Future Needs and Opportunities......................................................................................................40 Aquatic Vegetation/Wetlands.........................................................................................................................40 Future Needs and Opportunities......................................................................................................45 Fish Communities/Fishing.............................................................................................................................45 The fish community.........................................................................................................................46 Sport and commercial fishing.........................................................................................................53 Fish populations..............................................................................................................................61 Autecology/synecology...................................................................................................................65 Reproduction.....................................................................................................................65 Population estimates.........................................................................................................65 Movement/exploitation.....................................................................................................66 Feeding habits/trophic ecology.........................................................................................66 Behavior............................................................................................................................67 Alternative sampling programs.........................................................................................68 Future Needs and Opportunities......................................................................................................68 Reptiles and Amphibians...............................................................................................................................69 Future Needs and Opportunities......................................................................................................69 Mercury and Other Contaminants................................................................................................................................70 Future Needs and Opportunities......................................................................................................75 Paleoecology/Climate Change.....................................................................................................................................76 Future Needs and Opportunities......................................................................................................78 Conclusion....................................................................................................................................................................78 Acknowledgments........................................................................................................................................................80 References Cited..........................................................................................................................................................81 ii Figures Page Figure 1. Lake of the Woods/Rainy Lake watershed...................................................................................................1