Action Plan

Freshwater Pearl Mussel (Margaritifera margaritifera)

Freshwater pearl mussel is free living species and therefore all activities must be aimed at keeping the species in the wild. The action plan applies the gathered knowledge and experience of previous activities regarding the freshwater pearl mussel conservation efforts.

The main goal of the action plan is to achieve the existence of independently reproducing populations in natural environment. Three genetically distinct groups that form conservation units (CU) were identified within the Czech freshwater pearl mussel population. Conservation effort should be considered successful only when all phases of natural reproduction are started and accomplished in two out of three CUs. This goal is of uppermost importance.

Currently, there are estimates of 16,000 individuals of freshwater pearl mussel present in six main localities, other population fractions occur in other minor localities. We analyzed the population size, age structure, course of parasitic and interstitial phase of life cycle and the habitat quality at all localities of current occurrence of freshwater pearl mussel. Afterwards, we distinguished three categories according to the quality of localities and populations: priority localities (category I: Blanice and Zlatý potok), important localities (category II: Lužní potok, Bystřina, Teplá Vltava, Malše) and then extinct or near to extinction localities (category III: 9 streams). The categorization of the localities is mirroring the present situation and may be subjected to change.

Following differentiated long–term objectives of the action plan were indentified:
Category I

Reaching and maintaining the high environment quality which enables the long-term and stable persistence of freshwater pearl mussel, its reproduction and population growth.

Category II

Improving the insufficient quality of the environment. The current situation stresses the adult mussels due to suboptimal life conditions and thus additionally blocks the successful reproduction cycle.

Category III

Checking the presence and the status of freshwater pearl mussel in the locality and establishing the proper management accordingly.