Tracking two invasions for the cost of one: Opportunistically tracking the range expansion of non-native Palaemon macrodactylus in the Salish Sea through participatory science

While conducting early detection monitoring for invasive European green crab (Carcinus maenas), Washington Sea Grant Crab Team discovered a non-native shrimp Palaemon macrodactylus, hitherto unreported along Washington's portion of the Salish Sea. By examining prior data, and tracking this species closely over subsequent years, we were able to consistently monitor the spread and increase of this species across the region. The program and dataset enabled a highly quality-controlled and verified record of this species. Originating near the Canadian border, P. macrodactylus has spread southward into the main basins of Puget Sound and has been observed in Hood Canal as well. At sites where this shrimp has been consistently documented, the relative abundance over time has increased, indicating that the invasion has become established but not yet reached equilibrium. Similar to studies in other regions of the globe where it is found, we observed that P. macrodactylus favors estuarine habita..., , , # Tracking two invasions for the cost of one: Opportunistically tracking the range expansion of non-native Palaemon macrodactylus in the Salish Sea through participatory science

[https://doi.org/10.5061/dryad.sqv9s4ndp](https://doi.org/10.5061/dryad.sqv9s4ndp)

## Description of the data and file structure

This dataset was compiled in November 2024 to research the spread of the non-native shrimp, *Palaemon macrodactylus*, in the Washington portion of the Salish Sea. Two data sources were utilized:

* The Washington Sea Grant Crab Team monitoring network: wsg.uw.edu/crabteam
* A European green crab trapping dataset compiled by the Washington Department of Fish and Wildlife and staff at the Northwest Straits Commission for Drayton Harbor and Samish Bay, WA.

Full study descriptions are available in the manuscript: Grason et al. 2025 Frontiers in Marine Science.

### Files and variables

For all records the value NULL reflects no relevant information or data available.

**Data Files**:
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