For most people, the word “crustacean” brings to mind images of crabs, shrimp, lobsters, even krill. Crayfish is usually not in this list unless one is a chef or lives in Louisiana, where the state crustacean is the crayfish.

Crayfish are a keystone species, engineering habitats and serving as essential links in the food chain. However, habitat destruction, pollution and invasive species have left many species struggling to survive. In contrast, some species exported to Europe have flourished to the point that they compete with the native species and spread diseases.

To monitor and manage the crayfish population, scientists have created a global mapping platform: World of Crayfish (WoC). This first-of-its-kind atlas consolidates more than 100,000 observation records of 427 crayfish taxa into a free, searchable database.

Global tool for local challenges

Having such a map which shows a species' distribution and range size is foundational to species management. This was something that had been missing before the global map was created.

“About a third of crayfish are thought to be threatened or endangered, but for another 20-ish percent, we don't have the data available to even assess what their conservation status should be,” said atlas co-creator Caitlin Bloomer, teaching assistant professor in the Department of Natural Resources and Environmental Sciences, within the College of Agricultural, Consumer and Environmental Sciences at University of Illinois Urbana-Champaign. 

The global map addresses this gap. It compiles GPS data from scientific literature, museum collections, and field observations into a scalable world map, offering insights into crayfish distributions across continents. In this way, it provides a clear overall picture and thus facilitates international collaborations and discussion on the issue. 

The more-than-100,000 data points can be visualised on a world map which is scalable to 20-kilometre hexagons. According to Bloomer, this spatial scale is meaningful for conservation planning efforts but masks the exact locations of sensitive or vulnerable species, reducing risks like poaching or over-collection.

Managing an invasive species

Invasive crayfish species now pose a serious threat to biodiversity in Europe. They can disrupt ecosystems, outcompete native species, and impose costs on agriculture and fisheries. In some cases, public health is even put at risk. 

"WoC offers a science-driven approach to address this,” said co-creator Mihaela Ion, a researcher at the Institute of Biology Bucharest, Romanian Academy. 

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Enabling global collaborations

“Through collaboration with international experts and leveraging scientific advancements, WoC aims to combine ecological data with geospatial and predictive tools. These tools will support tailored analyses, such as mapping invasive species dynamics, evaluating habitat suitability, and predicting population trends,” project coodinator Lucian Pârvulescu, a professor at West University of Timișoara, Romania (WUT), said in a press release. 

Ultimately, the team hopes the atlas will empower researchers, policymakers and agencies to develop conservation assessments and policies to protect the crayfish while at the same time get the public to be more curious about this often-underrated species.

“The platform’s strength lies in its ability to merge diverse data streams into a cohesive system that generates actionable insights.”
- Lucian Pârvulescu, professor at WUT and WoC project coordinator