General Fisheries Commission for the Mediterranean - GFCM

Research programme on blue crabs

Two large non-indigenous species of the so-called blue crabs (the American Blue Crab, Callinectes sapidus, and the Blue Swimming Crab, Portunus segnis) have been present in the Mediterranean since at least the first half of the 20th century.

These species have large reproductive capacity and potential for expansion and also create negative interactions with traditional fishing gears such as gillnets or trammelnets, where they get entangled and negatively affect the catch and the fishing gears. Therefore their gradual appearance across the Mediterranean has been initially observed with large concern in both by fishers and conservation specialist. However, given their large size and good palatability, and thanks to the development of dedicated fishing gears, it became obvious that the development of efficient fishing gears was the only way to both control their expansion and create a new fishing opportunity where previously only negative effects on the sector were observed.

The need to develop a common management strategy to deal with population expansions and subsequent fisheries of these two crab species has emerged, especially so during the last years when populations largely increased both in number and geographically.

In this line, the GFCM issued Recommendation GFCM/42/2018/7 on the implementation of a regional research programme on blue crab in the Mediterranean Sea, in order to delimit and obtain all necessary information to be able to properly evaluate their populations status and maintain sustainable fisheries.




The research programme has six specific objectives, each corresponding to as many work packages (WP):


WP 1. Collect all possible relevant information on biological and ecological characteristics of the two species of blue crabs considered useful for a responsible management of the fishery.


WP 2. Collect fisheries independent data to provide valuable additional information on catch composition and on the overall affected faunistic community.  


WP 3.  Collect fisheries dependent data to obtain all the basic necessary information on blue crabs fisheries along the Mediterranean coasts to reach a level of knowledge that could provide a right management structure and process.


WP 4. Establish an ad hoc framework for blue crabs stock assessment considering both the habitats of the crabs and their particular fisheries characteristics.

WP 5. Understand both the technical/technological and socioeconomical components of blue crabs fisheries.


WP 6. Develop adaptive management measures at local, national and Mediterranean levels to keep blue crabs populations at low levels.

Learn more about the GFCM's research programmes.