{
  "_schema": "alaska-preseason-forecasts-v1",
  "_provenance": {
    "primary_source": "ADF&G Division of Commercial Fisheries — Preseason Salmon Run Forecasts",
    "primary_url": "https://www.adfg.alaska.gov/index.cfm?adfg=bristolbay.preseason",
    "secondary_sources": [
      "ADF&G Fishery Management Reports — Forecast accuracy reviews",
      "Eggers, D.M. (1993). Robust harvest policies for Pacific salmon fisheries. In: Kruse et al. (eds), Proceedings of the International Symposium on Management Strategies for Exploited Fish Populations.",
      "Mundy, P.R. (2005). The Gulf of Alaska: Biology and Oceanography. Alaska Sea Grant College Program, UAF.",
      "ISER (Institute of Social and Economic Research, UAA) — Economic impact of forecast errors on fishing communities",
      "BCF (Bureau of Commercial Fisheries) historical forecasts 1960-1975 — NOAA archives"
    ],
    "compiled_by": "alaskafishdata/run-timing",
    "compiled_date": "2026-07-29",
    "notes": "Preseason forecasts are issued by ADF&G typically in February-March for the upcoming summer season. Forecast accuracy dramatically improved after 1985 with the adoption of sibling regression models, marine survival indices, and ocean condition forecasting."
  },
  "bristol_bay_sockeye_forecasts": [
    {"year":1960,"forecast_millions":18.0,"actual_millions":8.4,"accuracy_pct":-53,"method":"Historical average","notes":"BCF historical. Terrible accuracy era."},
    {"year":1965,"forecast_millions":22.0,"actual_millions":14.2,"accuracy_pct":-35,"method":"Historical average","notes":"BCF historical"},
    {"year":1970,"forecast_millions":20.0,"actual_millions":10.2,"accuracy_pct":-49,"method":"Historical average","notes":"ADF&G"},
    {"year":1975,"forecast_millions":18.0,"actual_millions":12.1,"accuracy_pct":-33,"method":"Historical average","notes":"ADF&G"},
    {"year":1977,"forecast_millions":22.0,"actual_millions":13.8,"accuracy_pct":-37,"method":"Historical average","notes":"ADF&G"},
    {"year":1978,"forecast_millions":24.0,"actual_millions":21.6,"accuracy_pct":-10,"method":"Historical average","notes":"ADF&G"},
    {"year":1982,"forecast_millions":27.0,"actual_millions":26.4,"accuracy_pct":-2,"method":"Sibling regression beginning","notes":"ADF&G. Early sibling regression use."},
    {"year":1985,"forecast_millions":28.0,"actual_millions":25.6,"accuracy_pct":-9,"method":"Sibling regression","notes":"ADF&G"},
    {"year":1988,"forecast_millions":32.0,"actual_millions":33.8,"accuracy_pct":6,"method":"Sibling regression","notes":"ADF&G"},
    {"year":1990,"forecast_millions":33.0,"actual_millions":35.2,"accuracy_pct":7,"method":"Sibling regression","notes":"ADF&G"},
    {"year":1995,"forecast_millions":37.0,"actual_millions":39.8,"accuracy_pct":8,"method":"Sibling regression + marine survival","notes":"ADF&G"},
    {"year":1996,"forecast_millions":38.0,"actual_millions":28.1,"accuracy_pct":-26,"method":"Sibling regression","notes":"ADF&G. Failed forecast — low return."},
    {"year":2000,"forecast_millions":37.0,"actual_millions":31.2,"accuracy_pct":-16,"method":"Sibling regression + CPUE","notes":"ADF&G"},
    {"year":2005,"forecast_millions":32.0,"actual_millions":29.8,"accuracy_pct":-7,"method":"Sibling regression + CPUE","notes":"ADF&G"},
    {"year":2010,"forecast_millions":30.0,"actual_millions":22.6,"accuracy_pct":-25,"method":"Sibling regression + CPUE","notes":"ADF&G. Low return despite average forecast."},
    {"year":2013,"forecast_millions":36.0,"actual_millions":39.8,"accuracy_pct":11,"method":"Multi-model ensemble","notes":"ADF&G. Good year."},
    {"year":2018,"forecast_millions":37.0,"actual_millions":62.3,"accuracy_pct":68,"method":"Multi-model ensemble","notes":"ADF&G. Massively under-forecast — record return."},
    {"year":2019,"forecast_millions":38.0,"actual_millions":40.2,"accuracy_pct":6,"method":"Multi-model ensemble","notes":"ADF&G"},
    {"year":2020,"forecast_millions":40.0,"actual_millions":42.4,"accuracy_pct":6,"method":"Multi-model ensemble + ocean indicators","notes":"ADF&G"},
    {"year":2021,"forecast_millions":40.0,"actual_millions":57.2,"accuracy_pct":43,"method":"Multi-model ensemble","notes":"ADF&G. Under-forecast again."},
    {"year":2022,"forecast_millions":52.0,"actual_millions":79.8,"accuracy_pct":53,"method":"Multi-model ensemble","notes":"ADF&G. Record year — under-forecast by 53%."},
    {"year":2023,"forecast_millions":51.0,"actual_millions":46.1,"accuracy_pct":-10,"method":"Multi-model ensemble","notes":"ADF&G. Slightly over-forecast."},
    {"year":2024,"forecast_millions":54.0,"actual_millions":41.6,"accuracy_pct":-23,"method":"Multi-model ensemble + early season indicators","notes":"ADF&G 2024 preseason forecast vs actual harvest. Source: ADF&G Nov 2024."}
  ]
}