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Status and assessment, research, and restoration needs for lake herring in the Great Lakes Abstract: The Great Lakes Restoration Act sponsored a workshop to summarize the status of remnant lake herring stocks, review impediments, and develop recommendations for assessment, research and restoration in the Great Lakes. The report and framework resulting from the workshop held July 9-10 2003 will help managers and interested researchers develop actions to assess stocks and develop research. This research needs to assess and develop corrective actions as appropriate to limit the impacts of impediments and foster the recovery of remnant stocks. Given that most remnant stocks are small, spatially isolated, and genetically depleted it is expected that restoration stocking will be a necessary part of restoring lake herring populations in many parts of the Great Lakes. The workshop process was initiated by plenary summary presentations on the status of lake herring in all five of the Great Lakes and a number of inland lakes in Ontario. Presentations were also made on phylogeography, life history requirements, and dietary and rearing requirements. The thirty workshop participants then reviewed and assessed the importance of eight classes of impediments (e.g. habitat degradation, contaminants, exploitation, non-native biota, native biota, genetics, stock structure, spawning stocks and climate) rating them as to their potential to affect lake herring stocks on a lake by lake basis. The loss of stocks was considered the most important impediment now facing restoration of lake herring in the Great Lakes. This was followed by nonnative biota with threats at almost all trophic levels but overall, alewives being perceived as the greatest threat in this class of impediments. Relative to the impacts of non-native biota, habitat degradation, contaminants, exploitation, native biota, stock structure and climate were considered of less importance. As part of the impediment rating process, research approaches to assess the most important impediments were developed with emphasis on Lake Ontario. Approaches incorporating a combination of laboratory and field studies were advocated as they can provide data on actual mechanisms but applied to open lake stocks avoiding the largely circumstantial approach of the last century. Of the impediments in most need of research are those related to exotic species particularly those posed by alewives, a species suspected of impacting lake herring but where evidence to date has been of an anecdotal, speculative, and circumstantial nature. Restoration stocking should be applied where it will not affect an existing remnant stock or stocks using an experimentally determined most appropriate life stage. Numbers to stock are problematic due to lack of information on early life stage mortality rates and knowledge of factors that affect recruitment success. Management can play an important role in lake herring restoration by limiting exploitation, whether targeted or not, to the extent possible so as to preserve the few remaining remnant stocks. In addition there is a need to describe these remnant stocks in terms of population size, age composition, and genetic profile. Protecting remnant stocks is made all the more urgent by their low abundance and the steadily increasing influx of exotic species into the Great Lakes that may further elevate the risk of localized extirpations of lake herring. Despite best efforts, remnant stocks may still become irretrievably lost such that restoration becomes the only course of action to restore stocks and this will need to be supported by sufficient hatchery infrastructure.
Status and Assessment, Research, and Restoration Needs for Lake Herring in the Great Lakes Results of a Workshop Sponsored by The Fish and Wildlife Restoration Act Reported by: John Fitzsimons Department of Fisheries and Oceans Bayfield Institute 867 Lakeshore Road Burlington, Ontario Robert O’Gorman United States Geological Survey Biological Resources Division Great Lakes Science Center Lake Ontario Biological Station 17 Lake Street Oswego, New York 13126 2004 1
Page 1: GREAT LAKES FISHERY COMMISSION 2004
Page 5 and 6: Executive Summary The Great Lakes R
Page 7 and 8: Introduction The lake herring (Core
Page 9 and 10: Table 1: Potential Impediments to L
Page 11 and 12: Based on index netting, lake herrin
Page 13 and 14: Table 1: Summary of impediment rank
Page 15 and 16: Summary of Knowledge Gaps for Lake
Page 17 and 18: Figure 3: Summary of knowledge gaps
Page 19 and 20: 2/27/2004 Alewives and to a lesser
Page 21 and 22: 2/27/2004 Summary of Restoration Ne
Page 23 and 24: 2/27/2004 References Bence, J. R. a
Page 25 and 26: 2/27/2004 Appendix A Agenda Lake He
Page 27 and 28: 2/27/2004 Appendix B Participant Li
Page 29 and 30: 2/27/2004 Appendix C Summary of Sta
Page 31 and 32: 2/27/2004 Explanatory notes for imp
Page 33 and 34: 2/27/2004 Research Questions for Gr
Page 35 and 36: 2/27/2004 Appendix E Summary of Dis
Page 37 and 38: 2/27/2004 e. Native biota • Pisci
Page 39 and 40: 2/27/2004 Final Charge 2 for Group
Page 41 and 42: 2/27/2004 Explanatory notes for Gro
Page 43 and 44: 2/27/2004 Final Charge 1 for Group
Page 45 and 46: 2/27/2004 Issue: What are the early

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