The motive is not really tangible for the investigators of the police and experts of the water management office hof, said a spokesman of the upper franconian police on friday. A consideration, however, is that the bowls are to be used for decorative purposes, for example, for jewelry.
"For those who do the protection, it is a heavy blow", said the police spokesman. In september, unknown persons had again stolen numerous specimens, between 3000 and 4000 pieces. Between june and august 1500 shells had already been stolen. The bavarian ministry of the environment has offered a reward of 10,000 euros for information on the possible environmental crime – a violation of the federal nature conservation act.
The probability of finding a pearl in a shell is very small; however, exact figures vary widely. For example, the website of the bundes fur umwelt und naturschutz deutschland (BUND) states that only one of about 5,000 river pearl mussels (margaritifera margaritifera) produces a decorative pearl.
The strictly protected river pearl mussel can live more than 100 years and grow 15 centimeters long. It has a thick-walled, almost black shell. Mollusks place high demands on water quality. A river pearl mussel needs fast-flowing and oxygen-rich water and a substrate with stones, gravel or sand. Your ability to "cultivate" pearls once made this shell famous. In the past, pearls were made into jewelry.