Productivity Changes in Northeast US stocks

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.title[
# Productivity Changes in Northeast US stocks
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.subtitle[
## ICES ACOM, 6 February 2026 
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.author[
### Sarah Gaichas, ACOM Vice Chair
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## Stock productivity: multiple species, multiple sources

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Fish productivity from surveys, Mid Atlantic

<img src="20260206_ProductivityChanges_Gaichas_files/figure-html/productivity-anomaly-1.png" alt="Fish productivity measures. Small fish per large fish survey biomass anomaly in the Mid-Atlantic Bight. The summed anomaly across species is shown by the black line, drawn across all years with the same number of stocks analyzed." width="576" />
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Fish productivity from assessments, Mid Atlantic

<img src="20260206_ProductivityChanges_Gaichas_files/figure-html/mab-cf-1.png" alt="Assessment recruitment per spawning stock biomass anomaly for stocks mainly in the Mid-Atlantic. The summed anomaly across species is shown by the black line, drawn across all years with the same number of stocks analyzed." width="576" />
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.footnote[
Updated from <a name=cite-perretti_regime_2017></a>([Perretti et al., 2017](http://www.int-res.com/abstracts/meps/v574/p1-11/))
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## Recruits/Spawner from a single assessment (Herring)

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Change point analysis: 2024 SCAA model

![ASAP model recruits per spawner](https://github.com/sgaichas/HSpresentations/raw/main/docs/images/RecPerSpawner2024HerringASAP.png)

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.footnote[
Figures courtesy Jon Deroba, NOAA Northeast Fisheries Science Center
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Change point analysis: 2025 State space model

![WHAM model recruits per spawner](https://github.com/sgaichas/HSpresentations/raw/main/docs/images/RecPerSpawner2025HerringWHAM.png)

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# Use multiple lines of evidence for productivity change?

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## References

.table[
<a name=bib-perretti_regime_2017></a>[Perretti, C. et
al.](#cite-perretti_regime_2017) (2017). "Regime shifts in fish
recruitment on the Northeast US Continental Shelf". En. In: _Marine
Ecology Progress Series_ 574, pp. 1-11. ISSN: 0171-8630, 1616-1599.
DOI: [10.3354/meps12183](https://doi.org/10.3354%2Fmeps12183). URL:
[http://www.int-res.com/abstracts/meps/v574/p1-11/](http://www.int-res.com/abstracts/meps/v574/p1-11/)
(visited on Feb. 10, 2022).
]

## Additional resources

[Anomaly plots for lots of Northeast US stocks](https://noaa-edab.github.io/stockstatusindicator/MultisppRec2024.html#use-perretti-code-to-make-anomaly-plots)

.footnote[
Slides available at https://sgaichas.github.io/HSpresentations/ 
Contact: <sarah.gaichas@ices.dk>

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