SPASAM-MSE
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Overview

This page summarizes completed and ongoing research projects led or co-led by Chengxue Li, with a focus on spatial stock assessment, state-space modeling, and Management Strategy Evaluation (MSE). These projects integrate methodological development, simulation experiments, and applied fisheries management questions, often in close collaboration with scientists at NOAA Fisheries, universities, and international partners.

Completed Projects

1. SPASAM-MSE: A Generalized Spatial MSE Framework

Li, C.*, Deroba, J.J., Goethel, D.R., Berger, A.M., Schueller, A.M., Langseth, B.J., Hanselman, D.H., Liljestrand, E.M., and Miller, T.J. (2025)
SPASAM-MSE: a generalized spatial management strategy evaluation framework for exploring the impacts of spatial structure on stock assessments and management outcomes
Canadian Journal of Fisheries and Aquatic Sciences (accepted with minor revision)

This project introduces SPASAM-MSE, a flexible and extensible framework for evaluating fisheries management strategies under spatially structured population dynamics. Built on the Woods Hole Assessment Model (WHAM), SPASAM-MSE enables closed-loop simulation experiments linking spatial operating models, data generation, estimation models, projections, and harvest control rules.

Key contributions include:

  • A generalized spatial MSE architecture supporting multiple stocks, regions, fleets, and movement processes
  • Explicit treatment of movement, connectivity, natal homing, and metapopulation structure
  • Systematic evaluation of spatial misspecification between operating and estimation models
  • Quantification of management risk and spatial trade-offs in catch, biomass, and fishing mortality

2. Random Effects on Numbers-at-Age and Implicit Movement Dynamics

Li, C.*, Deroba, J.J., Berger, A.M., Langseth, B.J., Goethel, D.R., Schueller, A.M., and Miller, T.J. (2025)
Random effects on numbers-at-age transitions implicitly account for movement dynamics and improve stock assessment and management
Canadian Journal of Fisheries and Aquatic Sciences (Just-IN)
https://doi.org/10.1139/cjfas-2025-0092

This study demonstrates that introducing random effects on numbers-at-age transitions in state-space assessment models can implicitly absorb movement dynamics, even when movement is not explicitly modeled.

Key findings include:

  • Numbers-at-age random effects can partially capture unmodeled spatial processes
  • Improved estimation performance and management advice under spatially structured operating models
  • Reduced bias and improved robustness relative to deterministic age-transition models

Ongoing Projects

1. Is Single-Region Management Adequate for Spatially Structured Stocks?

Li, C.*, Deroba, J.J., Berger, A.M., Goethel, D.R., Langseth, B.J., Schueller, A.M., Liljestrand, E.M., and Miller, T.J.

This project evaluates whether single-region management frameworks are sufficient for managing spatially structured populations, with a particular emphasis on catch apportionment.

Core questions include:

  • When does spatial aggregation lead to biased or risky management advice?
  • How do alternative catch-apportionment schemes affect regional and stock-level outcomes?
  • Under what conditions is spatially explicit management necessary for sustainable and equitable outcomes?

2. Forecasting Fisheries Management under Data-Limited Futures

Led by: Jonathan Deroba (NOAA NEFSC)

This project examines how fisheries management strategies perform under future data-limited conditions, including reduced survey coverage and declining data quality in the US Northeast.

3. Wind Farm Mitigation in Spatial Stock Assessment

Led by: Chengxue Li (Stony Brook University)

This project explores how offshore wind development may affect stock assessment and management, and how alternative survey designs can mitigate potential impacts.

4. Handling Numbers-at-Age Random Effects in State-Space Projections

Led by: Emily Liljestrand (NOAA NEFSC)

This work develops pragmatic strategies for projecting state-space assessment models that include numbers-at-age random effects.

5. Climate-Informed MSE for Georges Bank Yellowtail Flounder

Led by: Sophie Wulfing, Gavin Fay (UMass Dartmouth)

This project integrates climate-driven processes into a spatial MSE framework for Georges Bank Yellowtail Flounder, examining how climate signals interact with assessment and management decisions.

6. Climate-Informed MSE for Black Sea Bass

Led by: Jeewantha Bandara, John Wiedemann (Rutgers University)

This study applies climate-informed MSE approaches to Black Sea Bass in the Northeast US, focusing on climate impacts on productivity, distribution, and management performance.

7. Practical Strategies for Addressing Catch Apportionment–Stock Boundary Mismatches

Led by: Carryn de Moor (University of Cape Town)

This project develops pragmatic and policy-relevant strategies for addressing mismatches between management catch apportionment schemes and biological stock boundaries. Using simulation-based and empirical case studies, the work evaluates how alternative apportionment approaches influence assessment accuracy, management performance, and equity across jurisdictions.