Fauna

Set of aquatic vertebrate animals which have the characteristic of being viviparous: the female lets the young grow in its belly, from which they get out alive. Marine mammals living in the oceans (cetaceans), as well as various freshwater species, such as the European otter, are aquatic mammals. Their mode of operation depends on the aquatic ecosystem where they live.

Articulated invertebrate animal which have the characteristic of breathing through trachea. Some insects have become aquatic (representing 3% of insects) but have retained this aerial breathing.

Vertebrate animal that has the characteristic of starting its life in the water. At birth, an amphibian breathes through its gills, like a fish. As an adult he now has lungs through which he can breathe freely, but he continues to absorb most of the oxygen he needs through the skin.

Aquatic vertebrate that breathes through gills and has both limbs represented by fins (pectoral and pelvic). Fish are usually oviparous.

Fish species belonging to the Clupeidae family (such as sardine and herring). The allis shad are among the anadromous species (i.e. which swim up rivers to spawn in the middle part of the rivers). As such, their populations have paid a heavy price to river development (dams without fish pass facilities, extraction of gravel changing the spawning, etc). Their presence is therefore a good indicator of the status of a river development. Two species of allis shad are present (and exploited) in French waters: the allis shad (Alosa Alosa) and twaite shad (Alosa fallax).

Endangered or vulnerable or rare or endemic species (i.e. living on a well-defined territory) listed either in Annex II of fauna and flora habitats directive, then special areas of conservation have to be designated, or in Annexes IV or V of the fauna and flora habitats directive, and for which protective measures must be implemented on the whole territory.

Enumeration of each taxa present in one or more basic hydro-biological samples taken during the same sample operation.