Striped nerite (Theodoxus transversalis) Danube Delta

The Striped Nerite (Theodoxus transversalis) is a rare species, which was last signaled in the Danube's Delta at the beginning of the '90s. This species developed at first in the marine environment, but afterwards it succeeded in forming colonies in continental aquatic environments.
The Striped Nerite (Theodoxus transversalis) prefers to inhabit large streams and rivers. It is a species which lives on the bottom of the water, on hard substrates. This invertebrate is a snail with a shell measuring between 7 and 8 mm in length and 5 mm in height. This species has individuals with different sexual organs. A female Striped Nerite lays between 50 and 200 eggs, which are protected by capsules. The eggs are laid on other individual's shells. Usually, the females choose to lay the eggs on the inferior side of the shell, in order to protect them.

Its favorite food consists of benthic algae. In order to mince them, the Striped Nerite uses a chitinous membrane, called radula.

This species is threatened by the eutrophication phenomenon, the pollution with fertilizers and by the human activities, performed near the waters.