Passes of the Aleutian Islands: First detailed description

Zimmermann, Mark; Prescott, Megan M.

doi:10.1111/fog.12519

Cited by 5 publications

(7 citation statements)

References 23 publications

(72 reference statements)

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“…This project occurred during a revision (Zimmermann & Prescott, In Review) of our original Aleutians bathymetry (Zimmermann et al., 2013), which played an important role in defining coral and sponge habitats (Rooper et al., 2014) and also in defining Essential Fish Habitat (EFH) (Turner et al., 2017). Our new Aleutians bathymetry will further improve our understanding of coral, sponge, and EFH, along with tides and currents modeled in oceanographic studies.…”

Section: Discussionmentioning

confidence: 99%

“…Unfortunately, oceanographers have only had low‐resolution maps of these underwater obstructions for estimating water flow (Aleutian Island passes: Favorite, 1974; Stabeno et al., 2005; Ladd et al., 2005, Bering Sea slope canyons: Clement‐Kinney et al., 2009, Bering Strait: Woodgate et al., 2006). We recently published a detailed and accurate map of the Bering Sea slope (Zimmermann & Prescott, 2018) and are updating a bathymetry map of the Aleutian Islands (Zimmermann et al., 2013), for shore‐to‐shore cross‐sectional pass measurements (Zimmermann & Prescott, In Review). False Pass, which we examine in this current manuscript, is just the first of dozens of Aleutian passes that we are redefining (Zimmermann & Prescott, In Review), updating the first estimates from 50 years ago (Favorite, 1967).…”

Section: Introductionmentioning

confidence: 99%

“…We recently published a detailed and accurate map of the Bering Sea slope (Zimmermann & Prescott, 2018) and are updating a bathymetry map of the Aleutian Islands (Zimmermann et al., 2013), for shore‐to‐shore cross‐sectional pass measurements (Zimmermann & Prescott, In Review). False Pass, which we examine in this current manuscript, is just the first of dozens of Aleutian passes that we are redefining (Zimmermann & Prescott, In Review), updating the first estimates from 50 years ago (Favorite, 1967).…”

Section: Introductionmentioning

confidence: 99%

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False Pass, Alaska: Significant changes in depth and shoreline in the historic time period

Zimmermann

Prescott

2020

Fisheries Oceanography

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Global ocean circulation is limited partly by the small passes of Alaska's Aleutian Islands, which restrict North Pacific Ocean water from flowing north into the Bering Sea and eventually to the Arctic, but the size and shape of these Aleutian passes are poorly described. While quantitatively redefining all of the Aleutian passes, we determined that the easternmost pass, with the cryptic name of False Pass, and with an unusual configuration of having both northern and southern inlets, had two or more inlets to the Bering Sea in the recent past, but that it has only a single northern inlet now (15,822 m 2 ), roughly equivalent in size to the southern inlet, Isanotski Strait (15,969 m 2 ). Navigational charts depict the opposite: two inlets to the Bering Sea now, but just one in older charts . This discrepancy inspired a thorough review of the hydrographic history from which we concluded that the second northern inlet did exist and hypothesize that it was a remnant of multiple former openings, or a single large opening, potentially allowing greater northward flow of warmer, fresher Alaska Coastal Current water. While the shoreline changes that we document here are often regarded as minor, ephemeral events, we document similar, nearby, permanent shoreline shifts which changed Ikatan Island into a peninsula and which shifted the Swanson Lagoon outlet over 3 km to the east.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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False Pass, Alaska: Significant changes in depth and shoreline in the historic time period

Zimmermann

Prescott

2020

Fisheries Oceanography

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“…We used a suite of rasters to characterize seafloor habitat throughout the Bering Sea (Supporting information). We interpolated depth (m) from several data compilations (Zimmermann et al 2013, Zimmermann and Prescott 2018, Mark Zimmermann [AFSC] unpubl., Steve Lewis [AKRO] unpubl., ArcMap, ESRI v10.7) using the natural neighbor method (Sibson 1981). We then used Benthic Terrain Modeler to derive slope (Horn 1981; 3‐cell radius) and bathymetric position index (BPI; Guisan et al 1999; 65‐cell radius) from the depth raster (ArcMap; Walbridge et al 2018) and used these estimates as additional seafloor terrain covariates because of their known effects on fish distributions (Laman et al 2018, Pirtle et al 2019).…”

Section: Methodsmentioning

confidence: 99%

Climate‐informed models benefit hindcasting but present challenges when forecasting species–habitat associations

et al. 2022

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Although species distribution models (SDMs) are commonly used to hindcast finescale population metrics, there remains a paucity of information about how well these models predict future responses to climate. Many conventional SDMs rely on spatiallyexplicit but time-invariant conditions to quantify species distributions and densities. We compared these status quo 'static' models with more climate-informed 'dynamic' SDMs to assess whether the addition of time-varying processes would improve hindcast performance and/or forecast skill. Here, we present two groundfish case studies from the Bering Sea -a high latitude system that has recently undergone considerable warming. We relied on conventional statistics (R 2 , % deviance explained, UBRE or GCV) to evaluate hindcast performance for presence-absence, numerical abundance and biomass of arrowtooth flounder Atheresthes stomias and walleye pollock Gadus chalcogrammus. We then used retrospective skill testing to evaluate near-term forecast skill. Retrospective skill testing enables direct comparisons between forecasts and observations through a process of fitting and forecasting nested submodels within a given time series. We found that the inclusion of time-varying covariates improved hindcasts. However, dynamic models either did not improve or decreased forecast skill relative to static SDMs. This is likely a result of rapidly changing temperatures within the ecosystem, which required models to predict species responses to environmental conditions that were outside the range of observed values. Until additional model development allows for fully dynamic predictions, static model forecasts (or persistence forecasts from dynamic models) may serve as reliable placeholders, especially when anomalous conditions are anticipated. Nonetheless, our findings demonstrate support for the use of retrospective skill testing rather than selecting forecast models a priori based on their ability to quantify species-habitat associations in the past.

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“…Temperature and salinity data collected in 2014-2017 by instrumented northern elephant seals in the Northeast Pacific were analyzed by Holser et al (2022) [7] to provide evidence of The Blob extending eventually to 1000 m depth. The vertical extent of The Blob is essential with regard to its propagation to the Bering Sea via the Aleutian Straits where the shallow depths of some passes will constrain water transport as discussed below; for more information, see the latest geomorphological study of the Aleutian passes by Zimmerman and Prescott (2021) [16]. Advection of SST anomalies along the PF was studied by Belkin and Shotwell (2012) [18] and Shotwell et al (2014) [19].…”

Section: The Blob's Emergence and Early Detectionmentioning

confidence: 99%

Echoes of the 2013–2015 Marine Heat Wave in the Eastern Bering Sea and Consequent Biological Responses

Belkin

Short²

2023

JMSE

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We reviewed various physical and biological manifestations of an unprecedented large-scale water temperature anomaly that emerged in the Northeast Pacific in late 2013. The anomaly dubbed “The Blob” persisted through 2014–2016, with some signs of its persistence through 2017–2018 and a possible reemergence in 2019. The tentative timeline of The Blob’s successive appearances around the Northeast Pacific is suggestive of its advection by currents around the Gulf of Alaska, along the Aleutians, into the Bering Sea, and eventually to the Bering Strait. During the initial phase of The Blob’s development in 2013–2014, advection along the Polar Front might have played a certain role. The extreme persistence and magnitude of The Blob resulted in numerous and sometimes dramatic ecosystem responses in the eastern Bering Sea. The multi-year duration of The Blob might have preconditioned the Bering Sea for the record low seasonal sea ice extent during the winter of 2017–2018 and the disappearance of the cold pool in 2016 and 2018 that profoundly affected zooplankton, invertebrates, fishes, seabirds, and marine mammals. A comparison of the time series of population responses across trophic levels suggests that The Blob lowered primary production during spring, increased production of small copepods and jellyfish, and reduced the efficiency of energy transfer to higher trophic levels. While the Bering Sea’s water temperature, seasonal sea ice, and cold pool seem to return to the long-term mean state in 2022, it remains to be seen if the Bering Sea ecosystem will completely recover. The two most likely alternative scenarios envision either irreversible changes or hysteresis recovery.

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Passes of the Aleutian Islands: First detailed description

Cited by 5 publications

References 23 publications

False Pass, Alaska: Significant changes in depth and shoreline in the historic time period

False Pass, Alaska: Significant changes in depth and shoreline in the historic time period

Climate‐informed models benefit hindcasting but present challenges when forecasting species–habitat associations

Echoes of the 2013–2015 Marine Heat Wave in the Eastern Bering Sea and Consequent Biological Responses

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