Table 2. Explanatory variables used for the GAM analyses. Subscript t refers to year.
| Variable | Description and source |
| ST (t) | Mean Barents Sea (BS) temperature in °C for and Januaryt to Decembert at 0–200 m depth in Atlantic water parts of the Kola section (70.5–72.5°N, 33.5°E) over 1921–2009a. |
| NAO(t) | Principal component based winter (Decembert-1 – Marcht) North Atlantic Oscillation (NAO) indexb |
| Cap (t) | Biomass of capelin in the BS in 103 tc. |
| Krill (t) | Euphausiids, abundance indices covering 1984 to 2004 from the Polar Research Institute of Marine Fisheries and Oceanography (PINRO)d. Data are for southern (Krill.S) and the northwestern (Krill.NW) BS. Krill is the sum of both area. |
| Herr (t) | Biomass of immature Norwegian Spring Spawning herring (1–2 years of age) in the BS in 103 t e. |
a
Tereschenko [63, http://www.pinro.ru/], bHurrell [64, https://climatedataguide.ucar.edu/sites/default/files/climate_index_files/nao_station_djfm.txt], cReport of the ICES Arctic Fisheries Working Group [65], Table 9.5 p 498, dZhukova et al., 2009 data used with permission, and eReport of the ICES Arctic Fisheries Working Group AFWG Table 9.6 p 499.