WATER QUALITY EFFECTS OF ABOVE-STREAM FISH FEEDERS IN LOW- NUTRIENT NORTH CAROLINA MOUNTAIN STREAMS By James F. Gilliam and Thomas A. Cady Department of Zoology College of Agriculture and Life Sciences North Carolina State University Raleigh, NC 27695-7617 December 1997 UNC-WRRI __________ WATER QUALITY EFFECTS OF ABOVE-STREAM FISH FEEDERS IN LOW- NUTRIENT NORTH CAROLINA MOUNTAIN STREAMS James F. Gilliam and Thomas A. Cady Department of Zoology College of Agriculture and Life Sciences North Carolina State University Raleigh, NC 27695 “The research on which this report is based was financed by the United States Department of the Interior, Geological Survey, through the N. C. Water Resources Research Institute.” “Contents of the publication do not necessarily reflect the views and policies of the United States Department of the Interior, nor does mention of trade names of commercial products constitute their endorsement by the United States Government.” Project No. 70130 ii ACKNOWLEDGMENTS Many individuals aided in the completion of this project. Jim Borawa, Regional Fisheries Biologist, North Carolina Wildlife Resources Commission, initiated the supplemental feeding project, and welcomed our involvement in assaying for water quality effects. Gratitude is extended to the personnel at the Water Quality Section1 of the North Carolina Department of Environmental Management, especially David Lenat and David Penrose, for consultation on invertebrate identifications and for the permission to utilize the agency's model for bioassessment. We also thank Dr. Jeff Hinshaw, Ron Thalman, and other staff at the North Carolina Mountain Horticulture, Crops, Research, and Extension Center for their assistance and use of facilities, and for processing water samples. We extend our appreciation to the personnel of the United States Forest Service, Pisgah and Nantahalah National Forests, for their assistance. Several graduate and undergraduate students aided in the completion of this project; we especially thank Maria Bartenbach, Dan Fiscus, Selina Heppell and Braden McCollum, all from North Carolina State University, for their help. Above all the students, we thank Brett Albanese for his excellent and dedicated work on this project, including field work under arduous conditions, and processing of seemingly endless invertebrate samples. We also thank Mr. and Mrs. Ray Gonce who provided rental property for the field crew, and showered the field crew with kindness and fresh vegetables. Finally, we thank the staff at Water Resources Research Institute for funding the project, and for their cooperation over the course of this project. Primary funding for the project was by the Water Resources Research Institute. Supplemental support was provided by the National Science Foundation, through the Research Experiences for Undergraduates (REU) program. 1 Presently the North Carolina Division of Water Quality, in the Department of Environment, Health, and Natural Resources. iii iv ABSTRACT From 1990-1993, pelletized fish food was added daily to 900-m stretches of four mountain streams by the North Carolina Wildlife Resources Commission, in an attempt to increase the standing crop and maximal size of wild trout. This report assesses water quality impacts of the feeders, through examinations of water chemistry and benthic invertebrate communities, as a companion paper to a separate report on the impact of feeding on the trout populations. Analyses of water chemistry (including five nutrient parameters: NH , NO , NO , PO , and total P) and 3 2 3 4 benthic invertebrate bioindicators yielded no statistically significant impacts when each of the five nutrients and the benthic invertebrate index were considered separately. All waters, whether fed or unfed, were judged to be of high water quality by the benthic invertebrate index, which is taken to be a long-term integrator of water quality. While none of the six of these metrics was statistically significant when considered alone, all six gave some indication of some impact, and a meta-analysis combining the six metrics yielded a statistically significant indication that the feeders had a subtle enriching impact. However, the increased nutrient levels, if present, were estimated to be small (about 0-30%) relative to the response of the main target trout species (about 100% increases in numbers and 400% increase in mass per unit area). We conclude that feeding at the intensity and spatial extent of the experiment can produce desired responses in the targeted trout populations without substantial local deterioration of water quality, but also note that expansion of the feeding program in intensity or spatial extent can be expected to produce water quality deterioration locally or in downstream areas, and that the feeding level at which water quality deterioration would become apparent is not known. v vi TABLE OF CONTENTS ACKNOWLEDGMENTS.........................................................................................iii ABSTRACT...............................................................................................................v LIST OF FIGURES....................................................................................................ix LIST OF TABLES.....................................................................................................xi SUMMARY AND CONCLUSIONS........................................................................xiii RECOMMENDATIONS...........................................................................................xv INTRODUCTION......................................................................................................1 METHODS................................................................................................................3 Study Sites.....................................................................................................3 Study Design..................................................................................................3 Response variables.........................................................................................5 Chemical analyses..............................................................................5 Invertebrate communities...................................................................5 Statistical analysis of chemical and macroinvertebrate data..............7 Fish communities...............................................................................7 RESULTS..................................................................................................................9 Chemical Parameters.....................................................................................9 Invertebrate Community Response................................................................16 Fish Community Response............................................................................16 Other Observations………………………………………………………….20 DISCUSSION............................................................................................................23 REFERENCES..........................................................................................................27 APPENDICES...........................................................................................................31 Appendix A. Invertebrate taxa list.................................................................31 Appendix B. Fish taxa list..............................................................................45 vii viii LIST OF FIGURES Page Figure 1. Location of the four study watersheds (asterisks) established by the North Carolina Wildlife Resources Commission (NCWRC), and and enlarged illustration of one of the watersheds (South Toe River, Yancy County, North Carolina)....................................................4 Figure 2. Water temperatures ........................................................................................10 Figure 3. Average discharges ........................................................................................10 Figure 4. Ammonia .......................................................................................................12 Figure 5. Nitrite .............................................................................................................12 Figure 6. Nitrate ............................................................................................................13 Figure 7. Dissolved reactive phosphorus .......................................................................14 Figure 8. Total phosphorus ...........................................................................................14 Figure 9. Biotic index scores from the NC Division of Environmental Management model ................................................................................19 Figure 10. Total number of Ephemeroptera, Plecoptera, and Trichoptera ....................19 Figure 11. Mean individual masses of rainbow trout, mottled sculpin, and longnose dace .........................................................................................22 Figure 12. Number of rainbow trout, mottled sculpin, and longnose dace collected in each 300 m stream section ..................................................22 Figure 13. Percent change in numbers per hectare and mass per hectare of rainbow trout in the fed section relative to the section above the feeders, and percent change in nutrient parameters and invertebrate Bioclass............24 ix