Aleutian Islands 2022 Report Card (pdf)
For more information on individual Report Card Indicators, please see Description of Report Card indicators (p. 133). For more information on the methods for plotting the Report Card indicators, please see "Methods Description for Report Card Indicators" (p. 138).
* indicates Report Card information updated with 2022 data
To highlight the spatial dynamics and east to west gradients characterizing the Aleutian Islands, we divide the ecosystem into three ecoregions: the Western, Central and Eastern Aleutian Islands.
Region-wide
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The North Pacific Index (NPI) effectively represents the state of the Aleutian Low. Above (below) average winter (November - March) NPI values imply a weak (strong) Aleutian Low and generally calmer (stormier) conditions. The NPI has been positive during 5 of the last 6 winters, with the exception being the winter of 2018-2019. The systematically positive state of the NPI (i.e., weak Aleutian Low) is consistent with the overall decline in the PDO during the interval.
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The Aleutians Islands region experienced suppressed storminess through fall and winter 2021/ 2022
across the region, potentially favoring foraging of plankton-eating seabirds (Bond et al., 2011).
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Western Aleutian Islands
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The reproductive success of least and crested auklets, planktivorous seabirds at Buldir Island was above the long-term average in 2022, indicating that overall zooplankton availability was sufficient to support seabird reproductive success in 2022 and potentially other plankton eating commercial groundfish species.
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Forage fish trends, as indicated by their percent in the composition of tufted puffin chick meals, have varied over time, with episodic peaks lasting 1–2 years. In general, Ammodytes (sand lance) increased in seabird diets to the time series mean after been absent since 2010; age-0 gadids (pollock mostly), decreased below the time series average after last year’s peak; and hexagrammids (primarily Atka mackerel) were below the time series mean, decreasing from last year. We note tufted puffins had average reproductive success (compared to above average last year) and fed mostly on squid and sculpins, thus signaling potentially favorable conditions for fish foragers though not as favorable as last year. Not shown here, squid comprised 34% and sculpins 23% of tufted puffin chick meals. Likewise, 42% of horned puffin chick meals were composed of Atka mackerel. There were no seabird diets collected in 2020.
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The pelagic fish foraging guild biomass increased above the time series mean from 2018 to 2022. The increasing trend was due to increases in Atka mackerel, Pacific Ocean perch and northern rockfish biomass.
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The overall biomass of the fish apex predator foraging guild continued its long term decline driven by Pacific halibut and Kamchatka flounder. The decrease was somewhat offset by increases in the biomass of rougheye/ blackspotted rockfish, other skates, Pacific cod and large sculpins compared to those in 2018.
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Steller sea lion numbers continue to decline, with no signs of recovery. Non-pups have declined 97% since 1984.
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The amount of area trawled was not updated this year and there are no schools in the western Aleutians.
Central Aleutian Islands
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As indicated by their percent in the composition of tufted puffin chick meals forage fish were more abundant than last year with ammodytes (sand lance) near the time-series mean, and both gadids (pollock) and hexamgrammids (Atka mackerel) increasing to above and at the time series mean, respectively. Notably sablefish contributed to chick meals, supporting evidence that sablefish continue to do well in the ecoregion. Gadids were more common through the 1990s while hexagrammids are uncommon in this region. There were no seabird diets collected in 2020.
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The survey estimated biomass of pollock and northern rockfish increased 71% each compared to 2018, driving an increase in fish pelagic forager biomass from 2018 to 2022. In sharp contrast, Atka mackerel decreased to one of its lowest biomass in the area.
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Fish apex predator foraging guild biomass remained close to the time series mean with a slight decrease driven by Kamchatka flounder biomass in 2022 compared to 2018. Prior to this year, the guild biomass had been consistently increasing from its lowest point in 2012.
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Steller sea lions were surveyed in 2022, however counts in the eastern Aleutians are still being verified.
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School enrollment fell for the third year in a row. This is the lowest on the time series and is driven by the trend at Unalaska Elementary. The small communities have either closed schools (Nikolski, in 2009) or are at risk of closure if they fall under the 10 student threshold (False Pass with 11 students and Akutan with 20). As in the case in the central Aleutians, decreasing enrollment trends impact the stability of families living in those communities. This indicator is updated annually with data from the previous year.
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The amount of area trawled was not updated this year
Eastern Aleutian Islands
- As indicated by their percent in the composition of tufted puffin chick meals forage fish were not
as abundant as in past years with ammodytes (sand lance) at average levels, and both gadids
(pollock) and hexamgrammids (atka mackerel) below average. Not shown, euphausiids made up 34%
of the chick meals. This suggests puffins continue to respond to chnages in prey availability and that
forage fish may not be as available as in other years for fish-eating commercial groundfish. Gadids
were more common through the 1990s while hexagrammids are uncommon in this region. There were
no seabird diets collected in 2020.
- Pelagic forager biomass, apex predator biomass and Steller sea lion (SSL) non-pup counts were not
updated this year.
- The amount of area trawled increased in 2020, continuing its downward trend since 2018. Area
trawled had been increasing following the 2012–2014 measures aimed at increasing protection for
Steller sea lions. Changes in trawled area follows commercial fishing patterns, which may reflect
recent changes in economics, ownership, and fishing effort allocation. Despite this year’s increase,
trawled area remains within 1 to 3% through the time series. Note this indicator is updated annually
with data for the previous year.
- School enrollment fell for the second year in a row, from its highest in 2019 at 443 students
to 414 in October 2020. This is the lowest since the recent enrollment in 2016–17 of 400 and
408 students. This primarily reflects trends in Unalaska, whereas the small communities have either
closed schools (Nikolski, in 2009) or are at risk of closure if they fall under the 10 student threshold
(False Pass, 10 students and Akutan with 17). As in the case in the central Aleutians, decreasing enrollment
trends impact the stability to families living in those communities. This indicator is updated
anually with data for the previous year.
*North Pacific Index (Nov-Mar average) |
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download data(.csv) |
*Western AI Least Auklet reproductive success |
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download data(.csv) | *Western AI Crested Auklet reproductive success |
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download data(.csv) | *Western AI Ammodytes in Tufted Puffin diet |
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download data(.csv) | *Western AI Gadids in Tufted Puffin diet |
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download data(.csv) | *Western AI Hexagrammids in Tufted Puffin diet |
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download data(.csv) | *Western AI Pelagic Forager Biomass |
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download data(.csv) | *Western AI Apex Predator Biomass |
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download data(.csv) | *Western AI SSL non pup counts |
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download data(.csv) | Western AI Habitat Impacted by Trawls |
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download data(.csv) |
Figure 1: Region-wide and Western Aleutian Islands indicators. *indicates time series updated with
2022 data
Figure 2: Central Aleutian Islands indicators. * indicates time series updated with 2022 data.
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