Concentration of (A) fishery permits and (B) variability in fishery revenues for selected communities of the Kenai Peninsula Borough (source: Alaska Commercial Fisheries Entry Commission). Fisheries concentration is quantified using Simpson’s diversity index, with higher values indicating more concentration (less diversity). The coefficient of variation measures the SD (relative to the mean) of communities’ fishery revenue over time (1980–2014).
For more information, please see the following journal article: Schoen et al. 2017. Fisheries. “Future of Pacific Salmon in the Face of Environmental Change: Lessons from One of the World’s Remaining Productive Salmon Regions.”
From the Supplemental Information of Schoen et al. 2017:
"The number of permits owned by residents of the Kenai Peninsula has stayed relatively constant over time in both the drift- and set-net fisheries; in contrast, permits have generally migrated from other Alaskan communities to non-Alaskan communities, particularly in the set-net fishery (Supplemental figure S2). In the early years of the limited entry programs, the drift-net fishery was almost at full capacity, with nearly all permits being fished in any given year. In contrast, the set-net fishery has never been fully prosecuted, and has always had a sizeable amount of “latency” in permit use. Permit usage in both fisheries underwent a sharp decrease in the mid 1990s, likely due to a combination of declining returns (Figure 8) and ex-vessel prices (not shown) for nearly all salmon species, starting in the early 1990s."
