Ecology, management and impact of Chinese mitten crab in Flanders

The first Chinese mitten crab was found in Belgium in 1933 and rapidly expanded its population in the Atlantic region in the period 1933-1956. In the course of the 1950s the population decreased due to water pollution and expanded again in the period 1970-2001. The exact migration routes of Chinese mitten crab are unclear, but from the North Sea and the Scheldt the species uses rivers, canals and smaller watercourses as migration routes and all kinds of water bodies for growth and mating. Larval growth and oviposition are carried out in salt water. Consequently, crabs have been reported along all watercourses with a direct connection to the North Sea. The Scheldt and its tributaries form the core of the current distribution area of the species. The crabs are usually registered when they leave the water, for example during spring and autumn migration, when they are confronted with migration barriers (locks, mills, other obstacles). The number of crabs varies greatly from year to year. The water flow rate probably determines to a certain extent the intensity of the migration.

This project will gather knowledge on the ecology of the species needed to implement a sound management plan. The emphasis will be on:
(1) research into possible management methods for mitten crab
(2) research into the ecological impact of management and the impact at population level on mitten crab from current management by means of crab slits
(3) The development of population-ecological knowledge that can guide further management of mitten crabs in Flanders.

Keywords:beheer, fauna