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Aleutian Islands 2024 Report Card

For more information on individual Report Card Indicators, please see Description of Report Card indicators (p. 117). For more information on the methods for plotting the Report Card indicators, please see "Methods Description for Report Card Indicators" (p. 122).
* indicates Report Card information updated with 2024 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.

Western Aleutian Islands

*North Pacific Index (Nov-Mar average)

North Pacific Index Bullet

  • The North Pacific Index (NPI) effectively represents the state of the Aleutian Low Pressure System. Above average (below average) winter (Nov-Mar) NPI values imply a weak (strong) Aleutian Low and generally calmer (stormier) conditions. The NPI was average during winter 2023–2024 (Figure 12), while it had been positive during the last 4 years. The return to more neutral conditions this year may partially explain the stormier conditions and strong winds.

*Western AI Least Auklet Reproductive Success

*Western AI Crested Auklet Reproductive Success

WAI Least and Crested Auklet Bullet

  • Reproductive success was particularly poor this year for planktivorous auklets at Buldir Island. Three of the species (crested, parakeet and whiskered auklets) had both extremely late hatch dates and below-average breeding success, while only least auklets had above average reproductive success. The overall drop suggests that there was below average availability of zooplankton to support seabird reproductive success and potentially other plankton-eating commercial groundfish species.

*Western AI Ammodytes in Tufted Puffin Diet

*Western AI Gadids in Tufted Puffin Diet

*Western AI Hexagrammids in Tufted Puffin Diet

WAI Amm Gad Hex Bullet

  • 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 2024, Ammodytes (sand lance) were close to the time series average, as were those of age-0 gadids (pollock mostly). Hexagrammids (primarily Atka mackerel) were absent from their diet, but appeared to be replaced by squid. However, puffin reproductive success was low, which suggests that they prey they brought back to their chicks was not optimal. While some seabird nests were lost after heavy rains, the decreased reproductive success across multiple species indicates lower availability of forage fish and potentially less available prey for groundfish feeding on fish.

*Western AI Pelagic Forager Biomass

Western AI Pelagic Forager Biomass Bullet

  • The pelagic fish foraging guild biomass stayed above the time series mean and increased slightly from 2022 to 2024. The increasing trend was driven mostly by northern rockfish, although pollock had a small increase as well. In contrast, the biomass of Atka mackerel and Pacific ocean perch decreased.

*Western AI Apex Predator Biomass

Western AI Apex Predator Biomass Bullet

  • The overall biomass of the fish apex predator foraging guild continued declining driven by Pacific cod and arrowtooth flounder. The decrease was somewhat offset mostly by increases in the biomass of rougheye/blackspotted rockfish and other skates.

Western AI SSL Non-Pup Counts

Western AI SSL Non-pup Counts Bullet

  • Steller sea lion numbers continue to decline, with no signs of recovery. Non-pups declined 5.7% between 2008-2023.

Western AI Habitat Impacted by Trawls

Western AI Impact by Trawl Bullet

  • The amount of area trawled was not updated this year.

Central Aleutian Islands

*Central AI Pelagic Forager Biomass

Central AI Pelagic Forager Bullet

  • The pelagic fish foraging guild biomass decreased from 2022 to 2024, driven by Atka mackerel. The decrease was somewhat offset by increased biomass of pollock and Pacific ocean perch. Overall biomass is now close to the time series mean.

*Central AI Apex Predator Biomass

Central AI APEX Predator Bullet

  • The fish apex predator foraging guild biomass had a modest increase 2022 to 2024 but is still more than 1 SD below the long term average. Pacific halibut, arrowtooth flounder and skate biomass all declined, while Pacific cod, Kamchatka flounder and rougheye/ blackspotted rockfish biomass increased.

*Central AI SSL Non-Pup Counts

Central AI SSL Non-pup Bullet

  • Counts of non-pup Steller sea lions were statistically stable but below the long term mean. The trend is not the same in all rookeries: within the central Aleutians the two westernmost rookery complex areas are declining, while the two remained table. Pup counts declined from 2008 to 2023 in the three westernmost rookery complex areas and were stable in the one furthest east.

Central AI Habitat Impacted by Trawls

Central AI Trawl Habitat Bullet

  • The amount of area trawled was not updated this year.

Central AI School Enrollment

Central AI School Enrollment Bullet

  • School enrollment continued a decreasing trend in the 2023-2022 school year. The school at Adak was closed in 2023 after it opened with five enrolled students who subsequently left. Student enrollment started falling after the processing plant, one of the primary economic activities in the island, closed in 2020. Alaska schools need at least ten students to qualify for state funding. Amid rising operating costs and flat funding in general, small schools like those at Adak, Atka, and other small fishing communities, are at increasing risk of closure. Decreasing enrollment trends and/or school closures impact the stability to families living in those communities. This indicator is updated annually with data from the previous year.

Eastern Aleutian Islands

*Eastern AI Ammodytes in Tufted Puffin Diet

*Eastern AI Gadids in Tufted Puffin Diet

*Eastern AI Hexagrammids in Tufted Puffin Diet

Eastern AI Amm Gad Hex Bullet

  • Tufted puffin high reproductive success and the composition of the fish fed to chicks indicated that forage fish were abundant, particularly capelin and age-0 pollock, which may reflect good foraging conditions for fish-eating groundfish. Ammodytes (sand lance) and hexagramids (Atka mackerel) were below the time-series mean in the puffin chick diets, although hexagrammids are uncommon in this region.

*Eastern AI Pelagic Forager Biomass

Eastern AI Pelagic Forager Bullet

  • The biomass of Atka mackerel increased substantially in the bottom trawl survey ( 5x compared to 2022), offsetting decreases in Pacific ocean perch, pollock, and northern rockfish biomass and maintaining a similar biomass level of pelagic forager groundfish compared to 2022. Swings in Atka mackerel biomass are common in the area.

*Eastern AI Apex Predator Biomass

Eastern AI Apex Predator Bullet

  • The fish apex predator foraging guild biomass decreased 24%, driven by arrowtooth flounder, Pacific halibut the rougheye/ blackspotted rockfish complex. Offsetting the decrease, Pacific cod, large sculpins and other skates increased compared to 2022. The guild biomass had been consistently increasing from its lowest point in 2012 and in general has remained below average since 2016.

*Eastern AI SSL Non-Pup Counts

Eastern AI SSL Non-pup Bullet

  • In contrast to the other regions in the Aleutian Islands, non-pup and pup counts of Steller sea lions continue to steadily increase. The recent 2023 estimates show increases of 2.1% and 1.5% from 2008 to 2023. Increasing counts in this area offset declines observed in the other regions of the Aleutian Islands. In most regions, and population wide, stability in non-pup counts was preceded by stable pup counts.

Eastern AI Habitat Impacted by Trawls

Eastern AI Trawl Habitat Bullet

  • The amount of area trawled was not updated this year.

Eastern AI School Enrollment

Eastern AI School Enrollment Bullet

  • School enrollment had a slight improvement from 2022 to 2023. Enrollment at the elementary school in Unalaska peaked in 2019-2020 at 238 students compared to the current 187 (note peak in 2018-2019 was due to the combined elementary and high school students). 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 currently with 9 students and Akutan with 24). The generalized long-term decline in enrollment, except for Akutan, is a concern. As in the case of 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.

Key

  2019-2023 Mean   2019-2023 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