GOA Report Card - 2021

Western Gulf of Alaska 2021 Report Card (pdf)

For more information on individual Report Card indicators, please see \Report Card indicator Description and Methods" in the Appendix of this Report (p.264).

  • The Winter average PDO index (Dec.-Feb.) continued its negative trend in 2021, reflecting cooling sea surface temperatures in the GOA. PDO
  • Summer (June-August) 2021 sea surface temperatures in the western GOA were generally lower than 2020, returning to within 1SD of the long-term mean, although spring surface temperatures were elevated.
  • Mesozooplankton biomass (sampled April-Sept) decreased in 2020 to within 1SD of the long-term mean, measured by the continuous plankton recorder, indicating average foraging conditions for planktivorous predators. These data are not yet available for 2021.
  • Copepod community size slightly increased in 2020 (sampled April-Sept), to within 1SD of the long-term mean, but remains low, indicating there were slightly more large species available (often considered of higher nutritional quality). These data are not yet available for 2021.
  • Motile epifauna biomass, observed during 2021 AFSC bottom trawl survey (May-Aug), decreased from 2019 to 2021 but remains within 1SD of the long-term mean. The biomass of this guild is dominated by octopuses, hermit crabs, and brittle stars. Hermit crabs, brittle stars, and octopus are below their long-term means while other echinoderms are above their long term mean.
  • Trends in capelin, as sampled by rhinoceros auklets at Middleton Island (April-Aug.), continue to be minimal in seabird chick diets in recent years, including 2021 but still remain within 1SD of the long-term mean. They were abundant from 2008 to 2013, during a period of cooler ocean temperatures.
  • Fish apex predator biomass, observed during 2021 AFSC bottom trawl survey (May-Aug), increased from 2019 to 2021 to within just above 1SD below the long-term mean. The primary species driving these trends include Pacific cod biomass, continuing to stay above their low in 2017 but remain below their long term mean, Arrowtooth flounder, which has trended upward since their low in 2017 but also remain below their long-term mean, and sablefish which are well above their long-term mean.
  • Black-legged kittiwakes reproductive success in 2021 (June-July) increased from 2020 and remain within 1SD of the long-term mean at the Semidi Islands potentially indicating moderate prey availability for these surface-feeding seabirds.
  • Modelled estimates of western Gulf of Alaska Steller sea lion non-pup counts continued a slightly increasing trend from previous years, remaining within 1SD of the long-term mean in 2019, however realized counts for non-pups (not shown here) show the lowest values in this area since 2011. These data have not been updated since 2019.

*indicates time series updated in 2021 Mean Trend  
*Pacific Decadal Oscillation (winter)
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*Western GOA SST Jun-Aug
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Western GOA Mesozooplankton Biomass
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Western GOA Copepod Community Size
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*Western GOA Motile Epifauna Biomass
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*Western GOA Capelin in Rhinoceros Auklets Chick Diets
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*Western GOA Apex Fish Biomass
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Western GOA Black-legged Kittiwake Reproductive Success
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*Western GOA Steller Sea Lion Non-pups
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Figure 1: Western Gulf of Alaska report card indicators. See bullets and the full report for descriptions. * indicates time series updated with 2021 data




Eastern Gulf of Alaska 2021 Report Card

  • La Niña conditions prevailed in winter 2020/2021 (Multivariate ENSO Index: Dec./Jan.). La Niña conditions are predicted for winter 2021/2022.
  • Summer (June-Aug.) 2021 sea surface temperatures in the eastern GOA remain within 1SD of the long-term mean.
  • Total zooplankton density in in SEAK inside waterst (May-Aug) increased from 2020 but remains within 1SD of the long-term mean. This suggests improved foraging conditions for planktivorous fish, seabirds, and mammals.
  • The overall copepod community size (ratio of large calanoid copepods to total calanoid copepods) decreased to within 1SD of the long-term mean in 2021 (May-Aug) due to decreased densities of large copepods (although still above average) and increased densities of small copepods.
  • Motile epifauna biomass, observed during 2021 AFSC bottom trawl survey (May-Aug), decreased from 2019 to 2021 but remains within 1SD of the long-term mean. Hermit crabs, brittle stars, and other echinoderms are all below their long-term means. Eelpouts have also decreased from 2019 to 2021 but remain above their long term mean.
  • Estimated total mature herring biomass (age 3+) of Sitka herring in spring 2020 continued to increase to the largest value in the time series (since 1980), remaining greater than 1SD above the long-term mean. The two populations with ocean influence (Sitka Sound and Craig) were elevated while populations in SEAK inner waters and Prince William Sound increased but remained low. These data are not yet available for 2021.
  • Fish apex predator biomass, observed during 2021 AFSC bottom trawl survey (May- Aug), trended downward from a high in 2015 to their second lowest value over the time series in 2021, but remainnig just within 1SD of the long-term mean. The decrease over this time period has largely been driven by arrowtooth ounder which are at their lowest value over the time series, more than one standard deviation below their long term mean. Pacific halibut, sablefish, and Pacific cod, have all increased from 2019 and are above their long term means.
  • Growth rates of piscivorous rhinoceros auklet chicks remain 1SD below the longterm mean in 2021 (June-July), a pattern since 2015, suggesting that the adults were unable to find suficient prey to support optimal chick growth.
  • Modelled estimates of eastern Gulf of Alaska Steller sea lion non-pups counts continue an increasing trend above 1SD of the long-term mean through 2019. However, counts suggest that non-pup have been lower than predicted in 2019 and 2017. These data have not been updated since 2019.

  Mean Trend  
*Multivariate ENSO Index (MEI DecJan))
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*Eastern GOA SST Jun-Aug
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*Zooplankton Density Icy Straight (#/m3)
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*Eastern GOA Copepod Community Size
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*Eastern GOA Motile Epifauna Biomass
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*Sitka Herring Mature Biomass (tons)
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Eastern GOA Apex Fish Biomass
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Rhiniceros Auklet Chick Growth
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Eastern GOA Steller Sea Lion Non-pups
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  2017-2021 Mean   2017-2021 Trend
  1 s.d. above mean   increase by 1 s.d. over time window
  1 s.d. below mean   decrease by 1 s.d. over time window
  within 1 s.d. of mean   change <1 s.d. over time window
  fewer than 2 data points   fewer than 3 data points

Figure 2: Eastern Gulf of Alaska report card indicators. See bullets and the full report for descriptions. * indicates time series updated with 2021 data