MIT Sea Grant Center for Coastal Resources

Can we Predict the Spread of Introduced Crabs?
A Citizen Scientist Initiative:
Marine Invasive Species Monitoring Organization

Predicting the spread of non-native organisms in the oceans is difficult. Usually there is not enough data on the introduced species over a large enough geographic scale and for a long enough time to develop and test mathematical models. Collecting adequate data takes many people working together to identify a particular species and accurately record information. This project seeks to demonstrate that a large group of people working together can collect enough scientifically valid data for predicting the spread of recently introduced non-native crab species.

This project is designed to accomplish two goals. Firstly, it aims to train and validate the efforts of citizen scientists to collect data, and secondly, the data will be used to develop an invasion probability model for two crab species. European green crab (Carcinus maenas) and Asian shore crab (Hemigrapsus sanguineus) were selected as study organisms, because they have long temporal and large spatial scales and both possibly colonized the same initial state, New Jersey. Although the spread model will focus on well established invaders, the approaches developed for C. maenas and H. sanguineus could be extended to other marine invaders, such as mollusks, fish, echinoderms, tunicates, and other crustaceans.

The data, collected by citizens of seven states and presented through the link below, shows the abundance of male and female Asian shore and European green crabs. It also presents an absolute measure of the native crabs found in the same habitat. Early analysis depicts differences in the distribution of these crabs in their northern and southern ranges.

Crab Data

For more information about the project and how you can become involved by monitoring and/or contributing data, please visit the website:

Or contact the organizer of the project:
David G. Delaney
McGill University
Department of Biology
Montreal, Quebec
Canada, H3A 1B1
Lab: (514) 398-1833
Cell: (514) 585-8801
Fax: (514) 398-5069

The CSI MISMO project has been made possible through the contributions of many people and organizations. Click here for acknowledgements.


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  this page last updated on: 1 August, 2005