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Katie Lankowicz

@klankowicz.bsky.social

244 followers 1K following 14 posts

Fisheries spatial ecologist: Postdoc GMRI, Ph.D. UMCES. Caffeine enthusiast. 🏳‍🌈 she/her

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Katie Lankowicz @klankowicz.bsky.social · 13/01/2025

Bottom water temperatures across the Northeast US continental shelf have been warming, with changes in regional currents since ~2008 rapidly intensifying this trend. In the time since, cod stock centers of gravity have moved northeast and cod spatial ranges have condensed, especially for large cod.

Spatial location of abundance-weighted stock centers of gravity within the modeled domain. Stock area boundaries are represented by black lines. Results are separated by size class (columns) and seasons (rows). The southern portion of the Southern New England biological stock area is not represented so that more detail can be seen in the center of gravity shifts. Darker, more saturated colors represent stock centers of gravity earlier in the time series and lighter, less saturated colors represent stock centers of gravity later in the time series. Red gradients represent the Eastern Gulf of Maine (EGOM), greens represent Georges Bank (GBK), blues represent Southern New England (SNE), and purples represent the Western Gulf of Maine (WGOM).

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Katie Lankowicz @klankowicz.bsky.social · 13/01/2025

Model results indicated strong relationships between cod presence/absence and depth and bottom temperature. While the spatial strata underpinning design-based indices of abundance are often defined to have relatively homogeneous depths, they do not yet consider bottom temperature.

Conditional effect of bottom temperature and depth (columns) on the presence/ absence of small, medium, and large cod (rows).

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Katie Lankowicz @klankowicz.bsky.social · 13/01/2025

I've been developing these models for three size classes of cod (small: under 40 cm TL; medium: 40-70 cm TL; large: over 70 cm TL) at seasonal time steps (Spring: March-August; Fall: September-February) 1982-2021. I'm mostly interested in size-specific habitat associations and distribution shifts.

A description of Atlantic cod VAST models setup. There are separate models for distinct size classes of cod. Across all size classes, modeled temporal domain is 1982-2021 and cod density is assessed at seasonal (spring and fall) time steps.

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Katie Lankowicz @klankowicz.bsky.social · 13/01/2025

The approach--Vector Autoregressive SpatioTemporal (VAST) modeling--has the advantage of integrating these data to estimate density in areas with limited observations. Knowing both density and spatial area, you can then derive indices of relative abundance.

Spatiotemporal density at any time [1...n] can be modeled as a relationship between catch and static (e.g., depth) and dynamic (e.g., bottom temperature) conditions, allowing for the estimation of habitat associations and spatially explicit abundance.

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Katie Lankowicz @klankowicz.bsky.social · 13/01/2025

Improved knowledge of Atlantic cod biological stock structure in US and adjacent Canadian waters has led to a new spatial management framework. Recently, I've been working on spatiotemporal models of cod distribution built on a suite of fishery-independent surveys and environmental covariates.

Atlantic cod biological stock spatial strata within the US Northeast continental shelf large marine ecosystem (EGOM: Eastern Gulf of Maine; GBK: Georges Bank; SNE: Southern New England; WGOM: Western Gulf of Maine). Areas with year-round groundfishing closures are filled with crosshatches. Lines indicate the 50, 100, and 200 m isobaths, with darker lines representing deeper isobaths. Ecologically important regions are annotated on the map.

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Katie Lankowicz @klankowicz.bsky.social · 04/12/2024

A triumphant return to form, both for Fall Out Boy and my listening habits

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