Atlantic salmon in Maine, once abundant but now seriously depleted, were listed as endangered under the federal Endangered Species Act (ESA) in November 2000. The listing covers the wild fish in eight Maine rivers as a single "distinct population segment." The controversy in Maine that accompanied the listing led Congress to request the National Research Council's (NRC's) advice on the science relevant to understanding and reversing the declines in Maine's salmon populations. The charge to the NRC's Committee on Atlantic Salmon in Maine included an interim report focusing on the genetic makeup of Maine Atlantic salmon populations. This is the interim report. Understanding the genetic makeup of Maine's salmon is important for recovery efforts, because the degree to which populations in Maine differ from adjacent populations in Canada and the degree to which populations in different Maine rivers and tributaries differ from each other affect the choice of recovery options that are most likely to be effective. This report focuses only on questions of genetic distinctiveness. The committee's final report will address the broader issues, such as the factors that have caused Maine's salmon populations to decline and the options for helping them to recover.

Contents

• THE NATIONAL ACADEMIES
• COMMITTEE ON ATLANTIC SALMON IN MAINE
• BOARD ON ENVIRONMENTAL STUDIES AND TOXICOLOGY
• OCEAN STUDIES BOARD
• Acknowledgment of Review Participants
• Summary
• 1. Introduction
  • BACKGROUND
  • THE LISTING OF SALMON UNDER THE ENDANGERED SPECIES ACT
  • THE PRESENT STUDY AND REPORT ORGANIZATION
• 2. Biology and Evolution of Atlantic Salmon
  • NATURAL HISTORY OF ATLANTIC SALMON IN MAINE
  • CONSEQUENCES OF SALMON LIFE HISTORY
• 3. Current State of Atlantic Salmon in Maine
  • WILD POPULATIONS
  • STOCKING
  • AQUACULTURE AND ESCAPEES
• 4. Genetics of Wild Maine Salmon Populations
  • INTRODUCTION
  • OVERALL SUMMARY OF GENETIC STUDIES
• 5. Quality of the Data
  • BACKGROUND
  • OVERLAPPING VERSUS DISCREET GENERATIONS
  • FAMILIAL STRUCTURING OF SAMPLED FISH
  • POPULATION DESIGNATIONS
  • LIMITATIONS OF GENETIC ASSAYS
  • STATISTICAL CONSIDERATIONS
  • USEFUL INFERENCE
• 6. Conclusions
• References
• Appendix A Statement of Task
• Appendix B Meetings and Presenters

This project was supported by Grant No. 01-0008 between the National Academy of Sciences and the National Fish and Wildlife Foundation. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the organizations or agencies that provided support for this project.

NOTICE: The project that is the subject of this report was approved by the Governing Board of the National Research Council, whose members are drawn from the councils of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine. The members of the committee responsible for the report were chosen for their special competences and with regard for appropriate balance.