Integrating local and traditional knowledge and historical sources to characterize run timing and abundance of eulachon in the Chilkat and Chilkoot rivers Item Type Thesis Authors Olds, Allyson Leigh Download date 11/10/2021 08:41:30 Link to Item http://hdl.handle.net/11122/6814 INTEGRATING LOCAL AND TRADITIONAL KNOWLEDGE AND HISTORICAL SOURCES TO CHARACTERIZE RUN TIMING AND ABUNDANCE OF EULACHON IN THE CHILKAT AND CHILKOOT RIVERS By Allyson Leigh Olds, B.S. A Thesis Submitted in Partial Fulfillment of the Requirements for the Degree of Master of Science in Fisheries University of Alaska Fairbanks August 2016 APPROVED: Dr. Megan McPhee, Committee Chair Dr. Anne Beaudreau, Committee Member Dr. Courtney Carothers, Committee Member Dr. Brad Ryan, Committee Member Dr. Franz Mueter, Chair Fisheries Division Dr. S. Bradley Moran, Dean, School or Fisheries and Ocean Sciences Dr. Michael Castellini, Dean o f the Graduate School Abstract Eulachon smelt Thaleichthyspacificus are anadromous forage fish of the North Pacific Ocean that annually spawn in coastal rivers of North America in late winter and early spring. These spawning runs range from northern California to southwestern Alaska and provide important resources to nearby communities, indigenous cultures, and wildlife predators. However, eulachon life history is not well understood or documented throughout their range. In recent years, concerns for eulachon population abundances in the southern portions of their range have led to federal protection. Though there are no federal listings in Alaska, there have been local concerns documented for eulachon runs of the Chilkat and Chilkoot rivers since approximately 1990. However, eulachon run timing and abundance trends are difficult to detect due to limited available data and variability in eulachon runs. To document baseline information and explore patterns of eulachon runs of the Chilkat and Chilkoot rivers, we sought local and traditional knowledge from residents of nearby communities to document information about local uses, run timing, abundance, and wildlife observations related to eulachon runs. Observations of eulachon runs were integrated with historical records from newspaper articles and scientific reports to construct temporal trends in eulachon run timing and abundance. Based on the findings of this study, annual eulachon runs of the Chilkat and Chilkoot rivers generally occur for about a week or two between mid-April and mid-May. The arrival dates of eulachon runs often vary from year to year, but the timing appears to have shifted earlier, from mid-May to mid-April, over the past couple of decades. Abundance records were not sufficient to quantify trends. However, qualitative information regarding abundance did not suggest any clear trends in eulachon abundances of the Chilkat and Chilkoot rivers over the years, nor did there appear to be prominent local concerns about abundance declines. Many respondents suggested that eulachon populations were naturally too variable to be able to describe trends in abundance. Interviews also provided insight into local perspectives on eulachon life history and ecology. These results suggest that variability in eulachon run timing and abundance could be related to environmental conditions, including tidal height, river habitat, and water temperature. For a data-limited species like eulachon, integrating local observations and historical records offers a promising approach to documenting baseline information and improving the scientific understanding of eulachon runs and other environmental phenomena. iii Table of contents Page Title page ............................................................................................................................................... i Abstract ................................................................................................................................................ iii Table of contents ....................................................................................................................................v List of figures........................................................................................................................................ix List of tables ..........................................................................................................................................xi List of appendices .............................................................................................................................. xiii Acknowledgements............................................................................................................................. xv 1 Introduction......................................................................................................................................... 1 1.1 Cultural and ecological significance of eulachon .....................................................................1 1.2 Research need ............................................................................................................................. 2 1.3 Eulachon life history ...................................................................................................................3 1.4 Local and traditional knowledge of eulachon ...........................................................................4 1.5 Study area ....................................................................................................................................5 1.6 Research objectives .....................................................................................................................7 1.7 Thesis outline .............................................................................................................................. 9 2 Information sources and interview methods ...................................................................................11 2.1 Semi-structured interviews .......................................................................................................11 2.1.1 Community visits ...............................................................................................................11 2.1.2 Sampling frame.................................................................................................................. 12 2.1.3 Conducting interviews .......................................................................................................14 2.1.4 Reducing bias ..................................................................................................................... 16 2.2 Secondary sources..................................................................................................................... 17 2.2.1 Newspaper articles .............................................................................................................17 2.2.2 Published studies and reports ............................................................................................18 2.2.3 Other sources ...................................................................................................................... 19 2.3 Data integration and analysis................................................................................................... 19 3 Historical and contemporary roles of eulachon .............................................................................23 3.1 Tlingit culture ......................................................................................................................... 23 v 3.2 Harvesting ..................................................................................................................................26 3.3 Oil rendering............................................................................................................................. 27 3.4 Trade and other uses .................................................................................................................28 3.5 Additional activities ..................................................................................................................29 3.6 Summary ....................................................................................................................................30 4 Eulachon run timing and abundance ...............................................................................................31 4.1 Run timing .................................................................................................................................31 4.1.1 Run indicators....................................................................................................................32 4.1.2 River differences ................................................................................................................34 4.1.3 Run duration ....................................................................................................................... 35 4.1.4 Winter runs......................................................................................................................... 37 4.1.5 Temporal trends .................................................................................................................37 4.2 Abundance .................................................................................................................................39 4.2.1 Abundance indicators .......................................................................................................