Upper Great Lakes States Angler Estimates and Map Book Documentation,

Transcription

1 Upper Great Lakes States Angler Estimates and Map Book Documentation, Erin M. Burkett, Department of Social Sciences, Michigan Technological University Richelle L. Winkler, Department of Social Sciences, Michigan Technological University April 2018 Contact Information: Richelle L. Winkler Department of Social Sciences Michigan Technological University 217 Academic Office Building 1400 Townsend Drive Houghton, MI Tel:

2 This research was supported by Grant Number 2015 WIN from the Great Lakes Fishery Commission under the Human Dimensions of Great Lakes Fishery Management theme. The content is solely the responsibility of the authors and does not necessarily represent the official views of the Great Lakes Fishery Commission. Acknowledgements: The authors would like to thank staff at the Illinois, Indiana, Michigan, Minnesota, and Wisconsin Departments of Natural Resources (DNR) who helped us by providing access to fishing license and other key data. This includes Vic Santucci at the Illinois DNR; Jeremy Price, Brian Breidert, and Matt Burlingame at the Indiana DNR; Tracy Claramunt, Randy Claramunt, Kristen Kosloski, Phil Schneeberger, Nick Popoff, Jay Wesley, Kristen Shuler, and Jim Francis at the Michigan DNR; James Thompson, Jenifer Wical, Heather Kieweg, Lyn Bergquist, Melissa Treml and Don Pereira at the Minnesota DNR; and Justine Hasz, Kate Strom-Hiorns, Karl Scheidegger, Keith Warnke, Ben Beardmore, and Brad Eggold at the Wisconsin DNR. In addition, we would like to thank staff, especially Marc Gaden, at the Great Lakes Fishery Commission for their support in creating this database. The content is solely the responsibility of the authors (Winkler/Burkett) and does not necessarily represent the official views of the Illinois, Indiana, Michigan, Minnesota, or Wisconsin Departments of Natural Resources. Suggested Citation: Winkler, Richelle L., and Erin M. Burkett. Michigan Technological University. (2018). Upper Great Lakes States Angler Estimates and Map Book Documentation, Houghton, MI. 2

3 Table of Contents Introduction... 5 Uses for Angler Demographic Data... 5 Detailed Methods and Data Sources... 6 Angler Data... 6 Table 1. States included in the database and their data sources Table 2. Noteworthy fishing license exemptions or exclusions that impact the database... 8 Estimating Great Lakes Salmon/Trout Anglers... 8 Lake-Level Angler Estimates: Lake Huron, Lake Michigan, & Lake Superior Total Population Data for Calculating Rates Accessing the Data Map Book References Appendix A. Maps Showing Lake Assignments for Lake-Level Great Lakes Salmon/Trout Angler Estimates Appendix B. Summary of Imputed Unknown Sex and Ages Table 4. Number of anglers for which sex was imputed, by state, year, and license type Table 5. Number of observations missing ages by state, year, and license type Appendices C-R State-level Anglers and Populations, Variable Names and Descriptions Appendix C. Illinois Total Anglers Appendix D. Illinois Lake Michigan Salmon/Trout Anglers Appendix E. Illinois Population Appendix F. Indiana Total Anglers Appendix G. Indiana Lake Michigan Salmon/Trout Anglers Appendix H. Indiana Population Appendix I. Michigan Total Anglers Appendix J. Michigan Great Lakes Salmon/Trout Anglers Appendix K. Michigan Population Appendix L. Minnesota Total Anglers Appendix M. Minnesota Trout Anglers

4 Appendix N. Minnesota Lake Superior Salmon/Trout Anglers Appendix O. Minnesota Population Appendix P. Wisconsin Total Anglers Appendix Q. Wisconsin Great Lakes Salmon/Trout Anglers Appendix R. Wisconsin Population Appendices S-V Lakewide Anglers and Populations, Variable Names and Descriptions Appendix S. Lakewide Salmon/Trout Anglers Appendix T. Lake Huron Population Appendix U. Lake Michigan Population Appendix V. Lake Superior Population

5 Upper Great Lakes States Angler Estimates, Erin M. Burkett, Richelle L. Winkler Introduction This report documents the methodology used to prepare the Upper Great Lakes States Angler Estimates, Database and Map Book. The dataset includes estimates of the number of in-state resident recreational anglers from the states of Illinois, Indiana, Michigan, Minnesota, and Wisconsin. It also includes estimates of the smaller subset of anglers who fish the Upper Great Lakes (Lake Superior, Lake Michigan, or Lake Huron) or their tributaries for salmon/trout by state of residence and separately by lake fished. All estimates are broken down by year, single year of age, and sex. The associated Map Book shows angler participation rates, Great Lakes salmon/trout angler participation rates, and change in participation rates over time by county of residence and sex. Altogether, the Map Book includes a set of forty-nine maps that illustrate geographic patterns in angler participation across the Upper Great Lakes States. The dataset offers robust estimates of the number of anglers based on counts of fishing license sales provided through administrative records. Because they do not rely on surveys or sampling, the data don t suffer from errors such as self-reporting or non-response bias. They describe the demographic structure of angler populations by providing long-term data from five Great Lakes states in a manner that facilitates comparison across states, counties, age, and between males and females. Data are most accurate for total anglers residing in each state, and for Great Lakes salmon/trout anglers in Wisconsin and Illinois. We believe those data to be of high enough quality that they can be used without reservation. Great Lakes (GL) salmon/trout anglers in Minnesota and Indiana are estimated based on models (but controlled to observed trout stamp sales), and likely underestimate the real number of GL salmon/trout anglers in these states. Estimates for Michigan GL salmon/trout anglers are likely less accurate, as there are no trout stamp sales data available in Michigan for a control. Finally, estimates of GL salmon/trout anglers by lake (especially for Lake Huron) should be taken as an approximation. The Database and Map Book accompany a series of reports that summarize angler demographic analysis by age, time period, and birth cohort for male and female anglers and present population projections of future recreational anglers. These reports are available separately online, or by contacting the authors. Uses for Angler Demographic Data State fishery management agencies and other groups interested in angler demographic change can use this database to understand changes in the angler population and ultimately to inform management and marketing decisions, including Recruitment, Retention, and Reactivation or R3 programs. It should also be of interest to researchers seeking to understand angler population change or relationships between policy and environmental changes and angler 5

6 participation, and to angler groups or members of the public who want to better understand recreational fishing participation trends. Database users can track fishing participation over time by age and sex for each state or make state to state comparisons. They can also use these data to begin to examine relationships between birth cohort and fishing participation (e.g. Winkler and Warnke 2013, Burkett and Winkler 2017). Each year, approximately 1.8 million recreational anglers fish the Great Lakes (USDOI, USFWS & US Census Bureau 2006, 2011; FOC 2010), exceeding commercial fishing in both participant numbers and economic value (Bence & Smith 1999). These millions of anglers play a critical role affecting the region s fisheries, their related ecosystems, and fisheries management practices and policies (Cooke & Cowx 2004, Carpenter & Brock 2004, Lewin et al. 2006, Thayer & Loftus 2013). A substantial body of research on angler attitudes, motivations, values, and constraints tells us that demographic factors such as age and sex affect angler participation (Kuehn et al. 2013, Floyd et al. 2006, Siemer et al. 1994). Recent survey data suggests that the number of Great Lakes state anglers is declining and aging, which could have dramatic implications for agency funding, fisheries policy, and fisheries management strategies (USDOI, USFWS & US Census Bureau 2006, 2011; Bruskotter & Fulton 2013). Demographic change in the angler population will pose challenges and opportunities for Great Lakes region fisheries management. Dwindling numbers of anglers will result in waning revenues for conservation programs due to both the loss of revenue generated through license sales and the potential decline in federal funds from the Pittman Robertson Act. At the same time, cohort changes could affect the practicality of different management strategies and/or shift stakeholder power dynamics (see Arlinghaus 2006 for summary of implications of angler demographic change). However, broad-scale research into the details of demographic factors and demographic change over time is scarce. Part of the reason is that each state has its own fishing license structure and system for collecting this information, making analysis of long-term fishing license data or comparative studies difficult. This database aims to facilitate investigations into angler demographics among the five Upper Great Lakes states. Detailed Methods and Data Sources Angler Data The estimates in the angler datasets are based on anonymized fishing license sales data provided by staff within each state s Department of Natural Resources (Table 1). Each state has its own fishing license database, age requirements, and exemptions. Our lab reorganized the data into a consistent and comparable format that identifies unique in-state anglers by their age, sex, and state of residence each year. Unique individuals are only counted once per year, meaning that if an individual purchased more than one type of fishing license within the same calendar year they were only counted once. Individuals who purchase any type of fishing license are counted as anglers by their state of residence. Estimates of the number of unique individuals who fish the Great Lakes and their tributaries, up to the first barrier, for salmon or trout are noted as Great Lakes salmon/trout 6

7 anglers and are counted by both state of residence and by lake fished (see discussion below for how lake was assigned). The datasets include only in-state resident anglers; out-of-state residents are excluded. In some instances, the state DNR provided data that was already filtered by residency. When necessary, we determined in-state residency based on license type sold or zip code of residence. For the state of Michigan, a small number of observations (approximately 0.28% of records) were missing information that could be used to determine residency status, and these individuals were removed from the dataset published here. The years for which data are available vary by state. Digitized data were not available for Illinois and Indiana before 2005 or 2006, but in other cases these data are available back to 1999 or 2000 (Table 1). Terminal years are determined by our team s most recent contact and data sharing with state DNRs. Age was calculated based on date of birth and age on July 1 of the reference year. The number of anglers with missing date-of-birth information (and therefore missing age) are noted in the database files. For all states, licenses purchased by individuals over age 80 were combined into a single 80 age category which represents anglers age 80 and over. A few individuals, with age less than 2 or greater than 110 were re-coded as missing. Ages listed as 2-15 were put into a 15 year old age group, which includes children under age 16 (the age at which licenses are first required in some of the included states). In a relatively small number of cases, angler sex data were missing, and we imputed sex using the known proportions of males and females by age. In total, the number of cases missing age or sex values are small and never do they exceed 1.4% of license sales within a year for any state (see Appendix A for a summary of missing values). Table 1. States included in the database and their data sources. State Years Data source Age license first required Illinois Illinois Department of Natural Resources 16 Indiana Indiana Department of Natural Resources 18 Michigan Michigan Department of Natural Resources 17 Minnesota Minnesota Department of Natural Resources 16 Wisconsin Wisconsin Department of Natural Resources 16 Individuals who fish without a license are not included, and it may be that some of the individuals who do purchase a license do not fish. Individuals who purchased sportsmen, or hunt/fish combo licenses that include access to fishing are included. This means that this database includes individuals who may purchase a more inclusive license than they utilize (e.g. they hunt but don t fish, but because they purchased a more inclusive license are included here). 7

8 States that sell a Spousal or Combination (Married Couple) fishing license provided demographic data on both the primary and secondary license holder, and both are included here as unique anglers. Individuals who fish but did not purchase a fishing license because they are not required to (due to age or other exemptions) are excluded. States have unique rules exempting some individuals from requiring purchase of a fishing license. In some instances, individuals who were not required to purchase a license still do so. We removed these exempt individuals from the database to facilitate comparison between ages and states. 1 Noteworthy license exemptions (by state) are listed in Table 2. For a complete list of current fishing license exemptions, users should refer to each respective Department of Natural Resources website. Table 2. Noteworthy fishing license exemptions or exclusions that impact the database State Exemption Indiana Indiana residents born before April 1, Anglers ages 65 and older. 2 Minnesota Resident anglers over the age of 65 were not required to purchase a fishing license until Wisconsin Wisconsin residents born before Estimating Great Lakes Salmon/Trout Anglers Estimates of Great Lakes (GL) anglers only include those who fish Lakes Superior, Michigan, or Huron and their tributaries up to the first barrier for salmon/trout. These estimates are based on GL salmon/trout stamp license sales in Wisconsin and Illinois. Wisconsin and Illinois each require this specific license to fish the GL for salmon/trout. In these states, estimates of the number of GL salmon/trout anglers are simply based on license sales in the same manner as described above for total anglers. For this reason, estimates are highly reliable in Wisconsin and Illinois. Still, in Wisconsin licenses sold by charter boat businesses are not included in the data, because details of their age and sex are not available. These anglers make up a small proportion of total GL salmon/trout anglers in Wisconsin (approximately 1,200 anglers per year purchase their Salmon Stamp directly from a charter boat company out of approximately 1 For example, in Indiana some seniors choose to purchase the Voluntary Senior Annual license although they are exempt because they are born before April 1, These individuals were removed from our analysis. 2 We exclude Indiana anglers age 65 and older from the database because in 2008 the IN DNR implemented a $17 Senior Fish-For-Life license that is available for residents who are at least 64 years old. Once an angler purchases a Fish-For-Life license, they no longer show up in each years license sales data, making it difficult to track participation among seniors. 3 This partially explains why overall values are lower for ages 65 and over compared to these ages in later years. 8

9 60,000 total GL salmon/trout anglers - Jennifer McDonough, Wisconsin DNR, November 2016). This means that some individuals who fish from charters are not included in the Wisconsin estimates and, because we used the Wisconsin estimates to generate estimates for Illinois, Michigan, and Minnesota (see discussion below), these states are affected by this issue as well. Estimating GL salmon/trout anglers in Indiana, Michigan, and Minnesota required additional steps because these states do not currently require a license or stamp specific to fishing the Great Lakes for salmon and/or trout. We used the known GL salmon/trout angler data from Wisconsin to develop and apply a logistic regression model that predicts the proportion of total anglers who are also GL salmon/trout anglers based on the individual s age and sex and characteristics of their county of residence. This process assumes that patterns of GL salmon/trout fishing in these states are similar to fishing patterns in Wisconsin, after controlling for these characteristics. For these reasons, users should consider that the estimates of GL salmon/trout anglers in Indiana, Michigan and Minnesota are farther removed from direct license sales counts (real data) and are based on various assumptions (described in more detail below), and so contain more error. First, we developed a logistic regression model using Wisconsin data to predict GL salmon/trout angling in the year 2010 (year for which most accurate Census data are available). The model predicts the likelihood of any angler to fish the Great Lakes for salmon/trout (dependent variable) based on a set of independent variables including: single year of age, sex, living in a metropolitan vs. nonmetropolitan county (defined by the Federal Office of Management and Budget definition 2013), distance from county of residence to the nearest Great Lake shore (measured continuously as distance from county centroid to the nearest lake shore), and whether the county of residence borders a Great Lake (measured categorically as 0 or 1). All of these variables were statistically significant and substantively impactful, however, the model did not fit the known Wisconsin data as well as we would have hoped (pseudo r-squared= for males and for females). Still, when compared to observed data, the models predicted GL salmon/trout fishing in Wisconsin reasonably well. Observed and estimated stamp sales in Wisconsin are correlated at r=0.97. Absolute percent errors ranged from 0% to 58% by singleyear-of-age, sex, and year (when there are at least 100 observed anglers) with a median absolute percent error for age/year/sex combinations of 34% for females and 38% for males. Overall, our models tend to underestimate GL salmon/trout anglers in Wisconsin, with an average underestimate of total (all ages) female GL salmon/trout anglers of about 31% each year and an underestimate of about 39% for male anglers each year. This suggests that our estimates of GL salmon/trout anglers in Indiana, Michigan, and Minnesota may significantly underestimate the real number of GL salmon/trout anglers in these states. In the next step, we applied the Wisconsin regression coefficients to Michigan anglers (and their corresponding counties of residence) to predict the probability that any Michigan angler would fish the Great Lakes for salmon/trout. We then aggregated predicted probabilities by county, sex, and single-year of age to estimate the proportion of Michigan resident anglers who fished the Great Lakes for salmon/trout. Predicted proportions were next multiplied by the 9

10 matching known number of Michigan resident license sales (total anglers) each year between 2000 and 2014 to estimate the number of GL salmon/trout anglers over the 15-year study period. This approach generally assumes that the proportion of total anglers who are also GL salmon/trout anglers is consistent over time. In reality, the proportion in Wisconsin ranged from 13% in 2001 to 15.4% in 2007 with a mean value of 14.6% in the most recent ten years. In Michigan, our model assumes that approximately 6.6% of anglers are GL salmon/trout anglers. We used similar steps to estimate the number of GL salmon/trout anglers in Indiana and Minnesota. However, since Minnesota and Indiana both require a general Trout Stamp, we were able to adjust the process to incorporate this additional information to improve estimates of GL salmon/trout anglers in these states. The Trout Stamp sold in Indiana and Minnesota includes inland waters, as well as Great Lakes. To consistently identify Great Lakes salmon/trout anglers across states, we needed to identify the subset of Trout Stamp holders who fish the Great Lakes from Indiana and Minnesota. To do so, we started (as with Michigan) by applying the Wisconsin regression coefficients to Indiana and Minnesota angler data to generate a predicted probability of whether any Indiana/Minnesota angler would fish for salmon/trout in the Great Lakes in In Minnesota, we adjusted the county centroid distance to Lake Superior to 10 km for three northeastern counties (St. Louis, Lake, and Cook) because these are geographically large counties, but their populations are primarily distributed in the more urban areas along the Lake Superior shoreline, which makes the county centroid a misleading measure of the population s distance to Lake Superior. As with Michigan, the regression models for Minnesota and Indiana yield individual predicted probability values, which we then aggregated by county, sex, and single-year of age and divided by the total number of anglers to estimate an initial value for the proportion of resident anglers who fished the GL for salmon/trout in In the final steps, we controlled the estimates to observed Trout Stamp sales data. We divided the estimated number of Minnesota/Indiana resident GL salmon/trout anglers (found using the process described above) in 2010 by the known 2010 Trout Stamp anglers (by county, age, and sex) to estimate the proportion of trout anglers that are specific to the Great Lakes. In Minnesota, this proportion ranged from 19% of male trout stamp holders in Cook County and Lake County to less than 1% of male trout stamp sales in Rock County, where trout stamp sales were low and where distance from Lake Superior is high. In Indiana it ranged from 14% of male trout stamp holders in Porter County and Lake County to less than 1% of trout stamp sales in Posey County which is in southwestern Indiana far from Lake Michigan. We assumed this proportion was constant over time, based on the values found in 2010, and we multiplied it (always by single-year of age, sex, and county of residence) by the number of trout stamps sold in each year to generate the final estimate of the number of GL salmon/trout anglers. In order to consider the quality of these GL salmon/trout angler estimates, it is useful to compare them to estimates based on the National Survey of Fishing, Hunting, and Wildlife- Associated Recreation. Despite the fact that the National Survey is best used for understanding characteristics of anglers, and should not be taken as a good source of estimated numbers, these 10

11 are the only other publicly available data that offer similar information. Table 3 facilitates this comparison. For total in-state anglers, the estimates we have provided are generally lower than those estimated by the National Survey. This could be because our data do not include anglers over age 79 and because they do not include anglers who are not required to purchase a fishing license (under age 18 in some states or those born prior to a certain year in others- Indiana). Differences could also be related to sampling or reporting error in the National Survey. For GL salmon/trout anglers, data are only available from the National Survey for the states of Michigan and Wisconsin. In those states, our estimates match fairly well with those reported by the National Survey, in terms of the percent of total anglers who fish GL for salmon/trout (U.S. Department of Interior, U.S. Fish and Wildlife Service, U.W. Department of Commerce, and U.S. Census Bureau, 2011). Table 3. Total and Great Lakes (GL) Angler summary comparing our database to the National Survey of Fishing, Hunting, and Wildlife-Associated Recreation results for 2011 State Total unique in-state anglers GL anglers (salmon/ GL anglers (National % GL anglers % GL anglers (National Database National Survey trout only) Survey) (salmon/trout only) Survey) Illinois 592, ,000 38,051 Sample size too small 6.4 Sample size too small Indiana 366, ,000 10,012 Sample size too small 2.7 Sample size too small Michigan 875,174 1,744,000 57, , Minnesota 1,144,941 1,303,000 24,103 Sample size too small 2.1 Sample size too small Wisconsin 1,031, , , , Note: The ages used in these values varies slightly. The National Survey reports ages 16 and older, but our data only shows anglers required to be licensed and up to age 79 at the oldest (varies by state). National Survey data (2011) are those reported in the State Reports in Table 3 for Total State Resident Anglers, and Table 9 for Great Lakes Anglers, State Residents, Salmon. Lake-Level Angler Estimates: Lake Huron, Lake Michigan, & Lake Superior To generate lake-level GL salmon/trout anglers, we aggregated the state-level estimates of GL salmon/trout anglers (described above) into their respective lake(s) fished. This process was complicated by a number of factors. First, assumptions had to be made about which lake or lakes anglers fished. Residents of Minnesota were assigned to Lake Superior, while residents of Illinois and Indiana were assigned to Lake Michigan, as these are the only Great Lakes these states border. The process was more difficult and uncertain in Wisconsin (where residents could fish Lake Michigan and/or Lake Superior) and in Michigan (where residents could fish any combination of Lake Huron, Lake Michigan, or Lake Superior). In Wisconsin we first assigned anglers to the Great Lake nearest to their county of residence (by county centroid). Next, we recognized that some anglers fish more than one lake, and in some instances we assigned anglers to more than one Great Lake. This means that the sum 11

12 of anglers estimated for each Great Lake is greater than the sum of the number of Great Lakes anglers resident in each state. The proportion of anglers assigned to two or more lakes varied based on distance from their county of residence to each lakeshore. For example, if a county s distance from a particular lake was maximized, we assigned a small proportion of anglers to that far away lake, but 100% of anglers to the nearest lake, meaning the total percentage assigned is greater than 100% and some anglers are double-counted. For example, consider Milwaukee County, Wisconsin which directly borders Lake Michigan but is quite far from Lake Superior. We assumed that 100% of Milwaukee County GL salmon/trout anglers fish Lake Michigan, and that 5% of them also fish Lake Superior. This compares to Marathon County, Wisconsin (home to the city of Wausau in central Wisconsin) where we assigned 30% of GL salmon/trout anglers to Lake Superior and 90% to Lake Michigan. Assigned proportions were first determined based on distance from each lake, but were adjusted based on road networks/drive times and cultural knowledge of where Wisconsin anglers go to fish. Throughout, we assumed that these proportions are evenly distributed across age and sex groups. Maps in Appendix A show the proportion of Wisconsin GL salmon/trout anglers we assumed to fish Lake Michigan and Lake Superior for each county. In Michigan, we assigned estimated GL salmon/trout anglers to Lakes Huron, Michigan, and/or Superior using a process informed by data from the Michigan Statewide Angler Survey or Creel Program. Michigan DNR creel clerks record angler s zip code of residence when they survey anglers. We used this zip code data to assign surveyed anglers to their county of residence and generated maps for each lake using ArcGIS of the proportion of state-resident surveyed anglers who fish each lake. County-level proportions were calculated by dividing the number of surveyed GL salmonid anglers in each lake by the total number of GL salmonid anglers surveyed by the creel clerks across all three Upper Great Lakes. Assuming that creel surveys reach a geographically representative sample of GL salmon/trout anglers, these data should provide a robust understanding of which lakes anglers fish. We multiplied our Great Lakes salmon/trout angler estimates by proportions (averaged over time) for each county to assign anglers to each respective lake. As with Wisconsin, we allow anglers to fish in more than one lake. In some years and counties there was no creel survey data for anglers fishing Lake Superior, in which case, we assumed the mean value for fishing Lake Superior over the full time period, rather than assuming a zero which might artificially deflate Lake Superior estimates. Further complicating the process is that creel data reveal dramatic changes over time in angler effort in Lake Huron and Lake Michigan between 2000 and 2015 (see Figure 1). Changes in effort are likely associated with the collapse of the salmon fishery in Lake Huron in the mid- 2000s (Dunlop and Riley, 2013; Johnson and Gonder, 2013; Riley et al., 2008) and the subsequent declines in salmon stocking in Lake Michigan (GLFC, 2012; GLFC, 2016). This could mean that anglers shifted the lakes where they fish within the time period under analysis from Lake Huron in the early years towards Lake Michigan or Lake Superior in the mid-2000s. To account for this possibility, we created two average proportions of anglers who fish Lake Huron, one for the time period (pre-collapse) and one covering (collapse 12

13 period). Similarly for Lake Michigan, we created two average proportions, one for and another from See Appendix A for an overview of what proportion of each county s estimated GL salmon/trout anglers were assigned to each lake and how that varies over time. Figure 1. Total hours fished by non-charter anglers for salmonids, Total hours fished by non-charter anglers for salmonids, Lake Michigan Lake Huron Lake Superior Hours fished (in thousands) Year Data Source: Michigan Statewide Angler Survey Program; Chart created by the authors. A final complication impacting the Lake Michigan estimates was that license sales data for /2006 were not available in Illinois or Indiana. In order to estimate Lake Michigan anglers, including those from IL and IN, the team generated estimates of the number of expected anglers in those states by age for the years /2006, based on observed license sales by age and cohort in the later years, for which data are available, using a process similar to cohort survival population projections but going into the past rather than the future (backcasts). In summary, lake level estimates provide a general approximation of the number of GL salmon/trout anglers who fish each lake by age, sex, and year. Multiple assumptions and models had to be invoked to generate these estimates, and they should be used with caution recognizing a certain (unknown) degree of uncertainty. Data are more reliable for Lake Superior and Lake Michigan, than they are for Lake Huron, because more real data from Wisconsin and Illinois are included. While the overall numbers of anglers by lake and participation rates by lake are uncertain, the age and sex structures of anglers should be fairly accurate, because there is no indication that the models/assumptions used would shift age or sex structure. 13

14 Total Population Data for Calculating Rates To facilitate the construction of participation rates, the dataset also includes estimates of the total state-resident population by single-year of age and sex as published by the US Census Bureau Population Estimates program. This means that if a user wants to calculate the proportion of Michigan resident females age 30 who fished in 2014, he/she could divide the angler estimate by the total population estimate for women within that age group. Total population estimates represent the population on July 1 of each year (midyear population) and are published in the U.S. Census Bureau, Intercensal Population Estimates. Our team did not modify total population estimates, other than to group them according to age and sex so that they correspond with the angler estimates we produced. Specific files used included: Intercensal Estimates of the Resident Population by Single Year of Age, Sex, Race, and Hispanic Origin for the United States: April 1, 2000 to July 1, 2010; Annual Estimates of the Resident Population by Sex, Race, and Hispanic Origin for the United States, States, and Counties: April 1, 2010 to July 1, 2014; 7/1/2015 State Characteristics Population Estimates; and 7/1/2016 State Characteristics Population Estimates. Accessing the Data Data are provided in.csv format which is compatible with Microsoft Excel and other data management and statistics programs. Data are also provided in.dta format for use in Stata Data Analysis and Statistical Software. Database users can download data by state, license type, or Great Lake. Metadata, including variable names and labels, are provided in.csv for importing into Stata or other statistics program. Metadata are intended to be machine readable data labels but not a replacement for the complete information provided in this document. Variable names and descriptions are also available in text description in Appendixes B-U below. Map Book The map collection includes a set of PDF files which show geographic patterns and trends in recreational fishing by county of angler residence for each state and lake. It includes maps showing (1) the total number of anglers; (2) the fishing participation rate (number of anglers divided by the population in residence); and (3) change in the fishing participation rate over time (calculated as the rate at time {t+1} minus the rate at time {t}). The primary data source for the maps is the annual license sales databases manipulated into angler estimates as described above. The maps only include in-state anglers and residents age 16-79, 17-79, or 18-79, depending on the first age a fishing license is required in each respective state. Note that anglers are counted in their county of primary residence, which could differ from the county or counties where they fish. 14

15 References Burkett, E.M. and Winkler, R.L Recreational Fishing in Wisconsin: Using an Age-Period- Cohort approach to understand fishing participation. Michigan Technological University. Houghton, MI, USA. Bence, J. R., & Smith, K. D. (1999). An overview of recreational fisheries of the Great Lakes. Great Lakes Fisheries Policy and Management: A Binational Perspective, Bruskotter, J. T., & Fulton, D. C. (2007). The influence of angler value orientations on fisheries stewardship norms. In American Fisheries Society Symposium (Vol. 55, pp ). Carpenter, S., & Brock, W. (2004). Spatial Complexity, Resilience, and Policy Diversity: Fishing on Lake-rich Landscapes. Ecology and Society, 9(1). Cooke, S. J., & Cowx, I. G. (2004). The Role of Recreational Fishing in Global Fish Crises. BioScience, 54(9), Dunlop, E. S., & Riley, S. C. (2013). The contribution of cold winter temperatures to the 2003 alewife population collapse in Lake Huron. Journal of Great Lakes Research, 39(4), Fisheries and Oceans Canada Survey of Recreational Fishing in Canada. Floyd, M. F., Nicholas, L., Lee, I., Lee, J.-H., & Scott, D. (2006). Social Stratification in Recreational Fishing Participation: Research and Policy Implications. Leisure Sciences, 28(4), Great Lakes Fishery Commission (GLFC). FISHERY AGENCIES PROPOSE CHINOOK STOCKING REDUCTION TO SUSTAIN THE LAKE MICHIGAN FISHERY. Press release. Lake Michigan Committee. June 13, Great Lakes Fishery Commission (GLFC). PROPOSED SALMON STOCKING REDUCTIONS ANNOUNCED FOR LAKE MICHIGAN. Press release. Lake Michigan Committee. August 27, Johnson, J. E., & Gonder, D. (2013). Status of introduced salmonines. Great Lakes Fishery Commission. Special Publication, 13(1), 50. Kuehn, D., Luzadis, V., & Brincka, M. (2013). An Analysis of the Factors Influencing Fishing Participation by Resident Anglers. Human Dimensions of Wildlife, 18(5), Lewin, W.-C., Arlinghaus, R., & Mehner, T. (2006). Documented and Potential Biological Impacts of Recreational Fishing: Insights for Management and Conservation. Reviews in Fisheries Science, 14(4), Riley, S. C., Roseman, E. F., Nichols, S. J., O'Brien, T. P., Kiley, C. S., & Schaeffer, J. S. (2008). Deepwater demersal fish community collapse in Lake Huron. Transactions of the American Fisheries Society, 137(6), Siemer, W. F., & Brown, T. L. (1994). Motivations and Satisfactions of Lake Ontario Boating Salmonid Anglers. Journal of Great Lakes Research, 20(2), Simoes, J. C. (2008). Recreational angler surveys: Their role and importance national and the 2008 Michigan angler survey - ProQuest. (n.d.). Retrieved March 2, 2018, from 15

16 Simoes, J. C. (2014). Segmenting anglers by lifestyles, lake types, and management preferences (Ph.D.). Michigan State University, United States -- Michigan. Retrieved from Thayer, S. A., & Loftus, A. J. (2012). Great Lakes recreational fisheries and their role in fisheries management and policy. Great Lakes Fisheries Policy and Management: A Binational Perspective, 2nd Edn. Michigan State University Press, East Lansing, Michigan, USA, U.S. Department of the Interior, U.S. Fish and Wildlife Service, and U.S. Department of Commerce, U.S. Census Bureau National Survey of Fishing, Hunting, and Wildlife- Associated Recreation. Winkler, R., & Warnke, K. (2013). The future of hunting: an age-period-cohort analysis of deer hunter decline. Population and Environment, 34(4),

17 Appendix A. Maps Showing Lake Assignments for Lake-Level Great Lakes Salmon/Trout Angler Estimates Appendix A1: Maps showing assigned proportions of Wisconsin s resident Great Lakes salmon/trout anglers to Lake Superior and Lake Michigan. Lake Superior Assigned proportions (%), Wisconsin Lake Michigan Assigned proportions (%), Wisconsin

18 Appendix A2. Maps showing assigned proportions of Michigan s resident Great Lakes salmon/trout anglers to Lake Superior, Lake Michigan, and Lake Huron. Lake Superior Assigned proportions (%), Michigan Lake Michigan Assigned proportions (%), Michigan

19 Lake Michigan Assigned proportions (%), Michigan Lake Huron Assigned proportions (%), Michigan

20 Lake Huron Assigned proportions (%), Michigan

21 Appendix B. Summary of Imputed Unknown Sex and Ages Table 4. Number of anglers for which sex was imputed, by state, year, and license type Year State License Type Illinois All License Types Illinois Lake Michigan Salmon Stamp Indiana All License Types Michigan All License Types Minnesota All License Types Minnesota Trout Stamp Wisconsin All License Types Wisconsin GL Salmon/Trout Stamp Table 5. Number of observations missing ages by state, year, and license type Year State License Type Illinois All License Types Illinois Lake Michigan Salmon Stamp Indiana All License Types Michigan All License Types Minnesota All License Types ,255 1,477 1,775 1,847 1,875 2,037 2,225 Minnesota Trout Stamp Wisconsin All License Types Wisconsin GL Salmon/Trout Stamp

22 Appendices C-R State-level Anglers and Populations, Variable Names and Descriptions Appendix C. Illinois Total Anglers angler_age - Age of Resident Fishing License Holder on July 1 of Year of Purchase (80 includes ages 80 and older) sex - Sex of Resident Fishing License Holder (Female, Male, or Total) lic_sold Number of Unique Resident Fishing License Holders in 2006, All Types lic_sold Number of Unique Resident Fishing License Holders in 2007, All Types lic_sold Number of Unique Resident Fishing License Holders in 2008, All Types lic_sold Number of Unique Resident Fishing License Holders in 2009, All Types lic_sold Number of Unique Resident Fishing License Holders in 2010, All Types lic_sold Number of Unique Resident Fishing License Holders in 2011, All Types lic_sold Number of Unique Resident Fishing License Holders in 2012, All Types lic_sold Number of Unique Resident Fishing License Holders in 2013, All Types lic_sold Number of Unique Resident Fishing License Holders in 2014, All Types lic_sold Number of Unique Resident Fishing License Holders in 2015, All Types Appendix D. Illinois Lake Michigan Salmon/Trout Anglers angler_age - Age of Resident Fishing License Holder on July 1 of Year of Purchase (80 includes ages 80 and older) sex - Sex of Resident Fishing License Holder (Female, Male, or Total) lic_sold Number of Unique Resident Lake Michigan Salmon Stamp Holders in 2006 lic_sold Number of Unique Resident Lake Michigan Salmon Stamp Holders in 2007 lic_sold Number of Unique Resident Lake Michigan Salmon Stamp Holders in 2008 lic_sold Number of Unique Resident Lake Michigan Salmon Stamp Holders in 2009 lic_sold Number of Unique Resident Lake Michigan Salmon Stamp Holders in 2010 lic_sold Number of Unique Resident Lake Michigan Salmon Stamp Holders in 2011 lic_sold Number of Unique Resident Lake Michigan Salmon Stamp Holders in 2012 lic_sold Number of Unique Resident Lake Michigan Salmon Stamp Holders in 2013 lic_sold Number of Unique Resident Lake Michigan Salmon Stamp Holders in 2014 lic_sold Number of Unique Resident Lake Michigan Salmon Stamp Holders in 2015 Appendix E. Illinois Population age Age of Illinois Resident on July 1 sex Sex of Illinois Resident (Female, Male, or Total) pop Number of Illinois Residents Eligible for Fishing License in 2006 pop Number of Illinois Residents Eligible for Fishing License in 2007 pop Number of Illinois Residents Eligible for Fishing License in 2008 pop Number of Illinois Residents Eligible for Fishing License in 2009 pop Number of Illinois Residents Eligible for Fishing License in

23 pop Number of Illinois Residents Eligible for Fishing License in 2011 pop Number of Illinois Residents Eligible for Fishing License in 2012 pop Number of Illinois Residents Eligible for Fishing License in 2013 pop Number of Illinois Residents Eligible for Fishing License in 2014 pop Number of Illinois Residents Eligible for Fishing License in 2015 Appendix F. Indiana Total Anglers angler_age - Age of Resident Fishing License Holder on July 1 of Year of Purchase (80 includes ages 80 and older) sex - Sex of Resident Fishing License Holder (Female, Male, or Total) lic_sold Number of Unique Resident Fishing License Holders in 2005, All Types lic_sold Number of Unique Resident Fishing License Holders in 2006, All Types lic_sold Number of Unique Resident Fishing License Holders in 2007, All Types lic_sold Number of Unique Resident Fishing License Holders in 2008, All Types lic_sold Number of Unique Resident Fishing License Holders in 2009, All Types lic_sold Number of Unique Resident Fishing License Holders in 2010, All Types lic_sold Number of Unique Resident Fishing License Holders in 2011, All Types lic_sold Number of Unique Resident Fishing License Holders in 2012, All Types lic_sold Number of Unique Resident Fishing License Holders in 2013, All Types lic_sold Number of Unique Resident Fishing License Holders in 2014, All Types lic_sold Number of Unique Resident Fishing License Holders in 2015, All Types Appendix G. Indiana Lake Michigan Salmon/Trout Anglers angler_age - Age of Resident Fishing License Holder on July 1 of Year of Purchase (80 includes ages 80 and older) sex - Sex of Resident Fishing License Holder (Female, Male, or Total) estgl Estimated Number of Unique Resident Lake Michigan Salmon/Trout Anglers in 2005 estgl Estimated Number of Unique Resident Lake Michigan Salmon/Trout Anglers in 2006 estgl Estimated Number of Unique Resident Lake Michigan Salmon/Trout Anglers in 2007 estgl Estimated Number of Unique Resident Lake Michigan Salmon/Trout Anglers in 2008 estgl Estimated Number of Unique Resident Lake Michigan Salmon/Trout Anglers in 2009 estgl Estimated Number of Unique Resident Lake Michigan Salmon/Trout Anglers in 2010 estgl Estimated Number of Unique Resident Lake Michigan Salmon/Trout Anglers in

24 estgl Estimated Number of Unique Resident Lake Michigan Salmon/Trout Anglers in 2012 estgl Estimated Number of Unique Resident Lake Michigan Salmon/Trout Anglers in 2013 estgl Estimated Number of Unique Resident Lake Michigan Salmon/Trout Anglers in 2014 estgl Estimated Number of Unique Resident Lake Michigan Salmon/Trout Anglers in 2015 Appendix H. Indiana Population age Age of Indiana Resident on July 1 sex Sex of Indiana Resident (Female, Male, or Total) pop Number of Indiana Residents Eligible for Fishing License in 2005 pop Number of Indiana Residents Eligible for Fishing License in 2006 pop Number of Indiana Residents Eligible for Fishing License in 2007 pop Number of Indiana Residents Eligible for Fishing License in 2008 pop Number of Indiana Residents Eligible for Fishing License in 2009 pop Number of Indiana Residents Eligible for Fishing License in 2010 pop Number of Indiana Residents Eligible for Fishing License in 2011 pop Number of Indiana Residents Eligible for Fishing License in 2012 pop Number of Indiana Residents Eligible for Fishing License in 2013 pop Number of Indiana Residents Eligible for Fishing License in 2014 pop Number of Indiana Residents Eligible for Fishing License in 2015 Appendix I. Michigan Total Anglers angler_age - Age of Resident Fishing License Holder on July 1 of Year of Purchase (80 includes ages 80 and older) sex - Sex of Resident Fishing License Holder (Female, Male, or Total) lic_sold Number of Unique Resident Fishing License Holders in 2000, All Types lic_sold Number of Unique Resident Fishing License Holders in 2001, All Types lic_sold Number of Unique Resident Fishing License Holders in 2002, All Types lic_sold Number of Unique Resident Fishing License Holders in 2003, All Types lic_sold Number of Unique Resident Fishing License Holders in 2004, All Types lic_sold Number of Unique Resident Fishing License Holders in 2005, All Types lic_sold Number of Unique Resident Fishing License Holders in 2006, All Types lic_sold Number of Unique Resident Fishing License Holders in 2007, All Types lic_sold Number of Unique Resident Fishing License Holders in 2008, All Types lic_sold Number of Unique Resident Fishing License Holders in 2009, All Types lic_sold Number of Unique Resident Fishing License Holders in 2010, All Types lic_sold Number of Unique Resident Fishing License Holders in 2011, All Types 24

25 lic_sold Number of Unique Resident Fishing License Holders in 2012, All Types lic_sold Number of Unique Resident Fishing License Holders in 2013, All Types lic_sold Number of Unique Resident Fishing License Holders in 2014, All Types Appendix J. Michigan Great Lakes Salmon/Trout Anglers angler_age - Age of Resident Fishing License Holder on July 1 of Year of Purchase (80 includes ages 80 and older) sex - Sex of Resident Fishing License Holder (Female, Male, or Total) estgl Estimated Number of Unique Resident Great Lakes Salmon/Trout Anglers in 2000 estgl Estimated Number of Unique Resident Great Lakes Salmon/Trout Anglers in 2001 estgl Estimated Number of Unique Resident Great Lakes Salmon/Trout Anglers in 2002 estgl Estimated Number of Unique Resident Great Lakes Salmon/Trout Anglers in 2003 estgl Estimated Number of Unique Resident Great Lakes Salmon/Trout Anglers in 2004 estgl Estimated Number of Unique Resident Great Lakes Salmon/Trout Anglers in 2005 estgl Estimated Number of Unique Resident Great Lakes Salmon/Trout Anglers in 2006 estgl Estimated Number of Unique Resident Great Lakes Salmon/Trout Anglers in 2007 estgl Estimated Number of Unique Resident Great Lakes Salmon/Trout Anglers in 2008 estgl Estimated Number of Unique Resident Great Lakes Salmon/Trout Anglers in 2009 estgl Estimated Number of Unique Resident Great Lakes Salmon/Trout Anglers in 2010 estgl Estimated Number of Unique Resident Great Lakes Salmon/Trout Anglers in 2011 estgl Estimated Number of Unique Resident Great Lakes Salmon/Trout Anglers in 2012 estgl Estimated Number of Unique Resident Great Lakes Salmon/Trout Anglers in 2013 estgl Estimated Number of Unique Resident Great Lakes Salmon/Trout Anglers in