Methods
Study Area
Figure 5. Yukon River Statistical Areas. Source: (ADFG, n.d.)
The study area covered the entire Yukon Area in Alaska, including the Yukon River drainage and coastal waters from Point Romanof to the Naskonat Peninsula. Postseason harvest interviews were conducted in 33 communities located off the road system. The Lower Yukon Area included coastal waters and the Yukon River drainage downstream to Old Paradise Village (Districts 1, 2, and 3), while the Upper Yukon Area extended upstream from Old Paradise Village to the Canada border and included three major tributaries (Districts 4, 5, and 6) as seen in Figure 5. The Coastal District encompassed remaining coastal waters. Some communities were not surveyed due to their distance from the mainstem Yukon River and low historical salmon harvests. The term "Yukon Area" includes Districts 1–6 and the Coastal District, and these are further categorized into three "sections" Yukon Coastal District, Lower Yukon, and Upper Yukon which indicates their relative location along the Yukon River.
Subsistence Surveys
Data was gathered by the Alaska Department of Fish and Game from 1992 to 2022. The methodology used to estimate the total number of salmon harvested in subsistence and personal use fisheries involved collecting data from various sources. This included household surveys, subsistence and personal use permits, test fishery data, harvest calendars, and information from commercial fisheries. For surveyed communities, data from selected households were expanded to estimate the entire community's harvest. In permit areas, the harvest totals reported on returned permits were summed, but unreturned permits were not considered for expansion. While this approach provided a comprehensive view of the salmon harvest, it had limitations, particularly regarding unreturned permits, which might not have been included in the estimation. These methods were conducted according to 33 communities that actively harvest salmon along the Yukon River drainage.
The total salmon harvest was determined by questioning households about their group harvest, harvest area, and salmon retained. To ensure all subsistence fish were counted, households were asked about retained fish from the commercial fishery and any lost fish. Fish fed to dogs were allocated as dog food, regardless of the original intent. Household gear and gear types for specific salmon species were also inquired about, with a new question added in 2016 (Question 8A).
Figure 6. Yukon Area postseason subsistence salmon harvest survey form, 2016. (Alaska Department of Fish and Game)
Climate data has been generated with the ClimateWNA v4.62 software package, available at http://tinyurl.com/ClimateWNA, based on methodology described by Hamann et al. (2013). The reference climate grids utilize the Parameter Regression of Independent Slopes Model (PRISM) interpolation method to represent the current climate. Historical data spanning the period from 1901 to 2020 are derived from the CRU-TS 4.05 dataset, as documented in Harris et al.'s study in Scientific Data (2020, 7: 109). The climate datasets were taken from coordinates centrally located in each community.