It is characterized by a cylindrical mouth with no upper and lower palates, and a round sucker with sharp teeth in the funnel-shaped mouth, which can attract big fish. There is also a funnel-shaped sucker on the ventral surface of the head. The body is slender, eel-shaped, the skin is bare and scaleless, and there is a long dorsal fin on the back, which extends backwards to the tail and forms a caudal fin around the tail. In addition, there are no other fins on its body.

2 dorsal fins, well-developed mouth funnel, no mouth whiskers. The lamprey has only one nostril, which is located between the eyes on the top of the head. Developed eyes, pinecone eyes, with photosensitive effect. There are seven gill holes on both sides of its body behind its eyes, which is why it is called "lamprey". The inner ear has two semicircular canals. At the end of the nasopituitary capsule is the blind capsule.

Distribution and habitat

Lampetra tridentata is a polar species, which extends eastward from Lapland, Finland to kamchatka peninsula, Russia, and southward to the North Pacific along the coast of Japan and South Korea. It also inhabits the Arctic Ocean and Pacific Basin in Alaska and northwestern Canada, as well as the fresh water areas in northeastern Mongolia and China.

Relationship with human beings

An East Asian lamprey, which used to live in the ocean, became an invasive species after being accidentally brought into the Great Lakes of North America. As the adult lamprey of East Asia lives on the blood of other fishes, their invasion has caused great losses to the fisheries of the Great Lakes, especially the Salvelinus namaycush and the Coregonus migratorius.

grow

The growth of lamprey from East Asia can be divided into three stages: larval stage, metamorphosis stage and adult stage. It is found from unearthed fossils that its development stage has not changed for hundreds of millions of years.

Extended data:

growing development

Dioecious, it takes a long larval period to develop and metamorphose into an adult. Adults live a semi-parasitic life, which is harmful to fisheries. The whole body is nearly cylindrical, and the tail is flat. The body length can reach more than 60 cm. There are seven separate gill holes on both sides of the head, which are aligned with the eyes to form eight elephant-like points, so it is commonly called the eight-eyed eel. The nostril is single, located between the eyes on the back of the head, and there is a white skin spot on the back.

There is a funnel-shaped sucker on the ventral surface of the head, which is round when it is opened, and there are many soft and milky protrusions on the wrinkled skin around it. The mouth is at the bottom of the funnel, and there are many yellow horny teeth on both sides of the mouth. There is a tongue-shaped piston with horny teeth on it. The anus is located at the junction of trunk and tail, and there is a urogenital process in front of the anus. The skin is soft and smooth, without scales and underdeveloped lateral lines.

No lateral fin. There are two dorsal fins, the base length is about the same, and the dorsal fin at the back is connected with the caudal fin, and the fins are soft and fine. When living, the back is blue and green, and the abdomen is grayish white and slightly yellowish.

Lamprey is a fish of the class Circadian. There is no jaw, and it is full of sharp teeth, which is one of the characteristics of ancient fish ancestors. The gills are bag-shaped in the original state, with seven points on the left and right, arranged behind the eyes. The mouth is funnel-shaped, and there are circles of teeth in it. It is a round sucker that can attract big fish.

The tongue also has teeth attached. When the prey is sucked in the mouth, bite in, scrape the meat and suck blood. The body has no scales and is covered with a sticky liquid. The sea lamprey is 70 cm long; Body length of lamprey 15~ 19 cm.

References:

Baidu encyclopedia-lamprey