River lamprey

Description

The river lamprey (Lampetra fluviatilis) is a species of agnato fish (without jaws ) of the order Petromyzontiformes,one of the few current species of its class Hyperoartia.About 30-40 cm long,it has a circular mouth capable of gnawing;with it it is subject to its prey,behaving as a predator / parasite of the same.Live in shallow waters.It has a breeding cycle similar to salmon,since they are born in the rivers and then they go to the sea,and when the time comes to procreate they go back to the river.L.fluviatilis,has seven branchial orifices,characteristic of the agnates;They have a primary dorsal fin,a secondary dorsal fin and a caudal fin.The adult measure of river lamprey is 25 to 40 cm (10 to 16 inches) in rivers and up to 28 cm (11 inches) in lakes.Its very elongated body is of a uniform dark gray color above,slightly yellowish-whitish on the sides and underneath a pure white.Like all lampreys,these fish lack even fins and have a circular suction disk instead of jaws.They have a single nostril and seven small breathing holes on either side behind the eye.The teeth are sharp and it can be said that the stream lamprey is much smaller (Lampetra planeri) due to the fact that the two dorsal fins are more widely separated.