Michigan STATE OF MICHIGAN DNR DEPARTMENT OF NATURAL RESOURCES Number 17 August 27, 1997 History, Status, and Trends In Populations of Yellow Perch and Double-Crested Cormorants in Les Cheneaux Islands, Michigan Edited by James S. Diana and Glenn Y. Belyea and Richard D. Clark, Jr. www.dnr.state.mi.us FISHERIES DIVISION SPECIAL REPORT MICHIGAN DEPARTMENT OF NATURAL RESOURCES FISHERIES DIVISION Fisheries Division Special Report 17 August 27, 1997 HISTORY, STATUS, AND TRENDS IN POPULATIONS OF YELLOW PERCH AND DOUBLE-CRESTED CORMORANTS IN LES CHENEAUX ISLANDS, MICHIGAN Edited by James S. Diana School of Natural Resources and Environment The University of Michigan Ann Arbor, MI 48109 Glenn Y. Belyea Michigan Department of Natural Resources Wildlife Division Rose Lake Wildlife Research Center East Lansing, MI 48823 Richard D. Clark, Jr. Michigan Department of Natural Resources Fisheries Division Institute for Fisheries Research Ann Arbor, MI 48109-1084 The Michigan Department of Natural Resources, (MDNR) provides equal opportunities for employment and for access to Michigan’s natural resources. State and Federal laws prohibit discrimination on the basis of race, color, sex, national origin, religion, disability, age, marital status, height and weight. If you believe that you have been discriminated against in any program, activity or facility, please write the MDNR Equal Opportunity Office, P.O. Box 30028, Lansing, MI 48909, or the Michigan Department of Civil Rights, 1200 6th Avenue, Detroit, MI 48226, or the Office of Human Resources, U.S. Fish and Wildlife Service, Washington D.C. 20204. For more information about this publication or the American Disabilities Act (ADA), contact, Michigan Department of Natural Resources, Fisheries Division, Box 30446, Lansing, MI 48909, or call 517-373-1280. Printed under authority of Michigan Department of Natural Resources Michigan DNR Total number of copies printed 90 — Total cost $419.75 — Cost per copy $4.66 TABLE OF CONTENTS Page Chapter 1. General Introduction .................................................................................................... 1 Chapter 2. Description of the Study Area...................................................................................... 3 Chapter 3. Population Status and Diet of Cormorants in Les Cheneaux Islands Area.................. 5 Chapter 4. Population Dynamics and Fishery Statistics for Yellow Perch in Les Cheneaux Islands Area............................................................................................... 26 Chapter 5. Cormorants Counts.....................................................................................................42 Chapter 6. The Impact of Cormorant Predation on Yellow Perch in Les Cheneaux Islands, Lake Huron ................................................................................................... 47 Chapter 7. Summary and Conclusions......................................................................................... 71 Acknowledgments .............................................................................................................................. 75 References .................................................................................................................................... 76 Appendix 1. List of Common and Scientific Names of Organisms................................................ 82 Appendix 2. Returns of Banded Cormorants from the Food Habit Study...................................... 83 Appendix 3. Retention of Metal Jaw Tags in the Stomachs of Captive Cormorants ..................... 85 Appendix 4. Loss of Jaw Tags by Yellow Perch............................................................................ 87 Appendix 5. Basic Program "Season.bas" for Estimating Seasonal Time Periods for Prey Consumption Analysis....................................................................................... 90 CHAPTER 1 GENERAL INTRODUCTION James S. Diana and Susan L. Maruca Since the late 1970s, the previously populations of cormorants will either contribute threatened double-crested cormorant (hence- to the further decline of yellow perch fisheries forth called cormorants; common and scientific or hold them at unacceptably low levels. names of organisms in this report are listed in In Les Cheneaux Islands of northern Lake Appendix 1) has made an impressive comeback Huron, the perch fishery, which had for decades in the Great Lakes (Scharf and Shugart 1981, been economically important to the area (Diana Ludwig 1984, Weseloh et al. 1995) and now et al. 1987), has experienced a marked decline numbers as many as 50,000 in Michigan waters since the late 1970s (Lucchesi 1988). Concern alone (Chapter 3). From approximately 1940 from anglers and local citizens helped generate a through 1960, cormorants were almost exirpated Michigan Department of Natural Resources from the Great Lakes due to dichloro-diphenyl- (MDNR) study in the mid-1980s, which trichloro-ethane (DDT)-related eggshell revealed that growth overfishing (over-harvest thinning and hatching deformities (e.g. Weseloh to the point where size at harvest declines et al. 1983). The recent explosion of cormorants dramatically) may have been at least partially has been attributed to a reduction in the responsible (Lucchesi 1988). A 175-mm concentration of DDT and its metabolites in the minimum size limit was instituted in 1987 in an water, as well as protection from human effort to reduce mortality for smaller fish, but it disturbance, increased nesting and foraging did not help the fishery as predicted (see Figure habitat on artificial reservoirs (Campo et al. 4-1). During this time abundance of cormorants 1993, Simmonds et al. 1995), and a ready food have increased in the area. Cormorants naturally supply in the form of introduced alewife in the reestablished at St. Martins Shoal, just west of Great Lakes (Price and Weseloh 1986, Ludwig Les Cheneaux Islands, in 1980 after many years et al. 1989). Since 1980, diet studies in the Great of absence, and in 1995 the local population Lakes show that alewife is the most prominent occupied three nesting colonies and numbered prey item for cormorants in nearly every approximately 4,000 breeding pairs plus an location where alewife and cormorants are estimated 2,000 to 3,000 juvenile birds (Chapter found together (Belonger 1983, Craven and Lev 3). 1987, Karwowski et al. 1992, Ludwig et al. The purpose of this project was to evaluate 1989, Ross and Johnson 1994, Weseloh and cormorant-perch interactions in Les Cheneaux Ewins 1994). Cormorants appear to be Islands area. In particular, we evaluated generalist feeders that consume prey species on population trends in cormorants and yellow the basis of energetic profitability, which often perch, then determined the effect of cormorant results in the consumption of commercially or foraging on the yellow perch fishery. This report recreationally important species such as stocked documents a series of independent but related trout or salmon fingerlings, yellow perch, and studies on various aspects of the project. Major walleye. funding for the project came from Michigan Yellow perch populations have been Department of Natural Resources, with declining in many areas of the Great Lakes for supplemental funding from the U.S. Fish and several decades, most likely as a result of Wildlife Service and the University of repeated recruitment failures (Lucchesi 1988, Michigan. Haas and Schaeffer 1992), and fisheries This report is subdivided into eight chapters managers are now concerned that predation and five appendices, each with separate authors pressures from the newly abundant and growing who researched each component. The main 1 project results are outlined in Chapters 3 to 6. Maruca, S. L. 1997. The impact of cormorant Each section is complete in itself (text followed predation on yellow perch in Les Cheneaux by figures and tables), except the References Islands, Lake Huron. Pages 50 to 73 in J. S. section, which was compiled for all chapters Diana, G. Y. Belyea, and R. D. Clark, Jr., combined. editors. History, status, and trends in Due to the multiple chapters and authors for populations of yellow perch and double- this document, we suggest that citations to crested cormorants in Les Cheneaux Islands, specific components of this work be made like Michigan. Michigan Department of Natural an edited volume. For example, citation of Resources Fisheries Division, Special information from Chapter 6 would be: Report No. 17, Ann Arbor. 2 CHAPTER 2 DESCRIPTION OF THE STUDY AREA Susan L. Maruca Les Cheneaux Islands are located on the north The study area boundary selected (Figure 2- shore of Lake Huron east of the Straits of Mackinac 1) was established in an effort to "contain" the near Cedarville, Michigan (Figure 2-1). The area entire yellow perch population within the study consists of at least 23 islands surrounded by area. Little information exists regarding yellow glaciated channels and bays that interconnect to perch movements in Les Cheneaux Islands area; form a physiographically diverse, largely however, Lucchesi (1988) found that none of oligotrophic aquatic ecosystem. Aquatic habitats in the 11,649 yellow perch he tagged during the area fall into three general categories: shallow, spawning in Mackinac, Sheppard, or Flower productive inner bays (0 to 3 m); deeper channels bays were recovered outside the islands. The and bays, often with some submergent vegetation (3 bounded study area contains approximately to