the lamprey
Petromyzon marinus Linnaeus, 1758
Order: Petromyzoniformes
Family: Petromyzonidae
Lampreia
Lamprey
sea lamprey
The lamprey is an autochthonous, demersal, euryhaline andanadromous(It is born in the river and grows, mainly, in the sea). In recent years there has been a loss of habitat as a result of the progressive construction of dams. Changing flows affect spawning sites.It is one of the most primitive and least evolved vertebrates in the animal world, with an estimated age of 400 million years.
Morphology
The lamprey has an eel-shaped body, a sucker-shaped mouth,scaleless and no paired fins. It has seven gill holes on each side of the anterior region of the body and one nostril on top of the head. The skeleton is made of cartilage, without bony parts. The dorsal fin is bipartite, the second continuous with the caudal fin. Color black or brown with a faint yellow color on the back and yellowish on the ventral area. The larvae (ammocetes) lack teeth and have rudimentary eyes. It can reach a length of more than a meter and weigh about 2.5 kg.It can live up to 9 years. ​There is no evidence in the Miño River of similar species such as theLampret fluviatiliseitherplaneri lampret.
Adulto
Adultos
Juvenil. Boca
Adulto
Photos: Carlos Antunes; Patricio Bouca, Mario Jorge Araujo
biology
​Species anadromous, demersal and euryhaline. Its life cycle is summarized in: it is born in the rivers, it goes down to the sea to reach maturity and it returns to the river to reproduce. The marine phase of the species still has big unknowns. After 2-3 years in the sea it reaches maturity and its reproductive instinct brings it back to the riverbeds.
In the Minho River, it migrates to spawn between December and June. During this migration, it does not feed andusually dies after breeding.
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In the place of reproduction, they attach themselves to the stones with the help of the buccal disc, which in the sea allows them to grab hold of prey to feed on their blood, and the male digs a hole in the sand in which the female lays 60,000 to 300,000 eggs approximately 1 mm in diameter. After preparing the nest, the female "hooked on a stone" allows the male to cling to her head and fertilizes the eggs.
Larvae (ammocetes) live in fresh water,for an estimated period of 3 to 5 years, feeding on debris and microorganisms, they do not have teeth and have rudimentary eyes. After metamorphosis, they descend the river to the sea (between January and March), living parasitically, feeding on the blood of fish such as salmon, trout, tarpon, among others. They often appear, at this stage of their life cycle, in fishing for eels.
Distribution
The lamprey is distributed on both sides of the North Atlantic, being present in North America and Europe. In northern Europe, the incidence is sporadic and rare (Norway). Migration in the rivers of Central Europe is also rare. In Western Europe, the most abundant populations of lamprey enter the large rivers that flow into the Atlantic: in France, the Loire River, the Dordogne River, the Gironde River, the Garonne River, etc.
In the Iberian Peninsula it is also very common, however, it is increasingly difficult for it to migrate to the headwaters of the rivers. In the Mediterranean Sea, the lamprey is less abundant.
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Its available habitat in the Miño river basin extends to the Frieira dam., which is about 80 km long. However, it also uses tributaries of the Miño River as breeding grounds, such as the Tea River and the first part of the Coura River.
Conservation
Species indigenous. The main pressure comes from habitat loss through dam construction, destruction of breeding grounds, and pollution. The available habitat ends at the Frieira Dam. The change in flow affects spawning locations.
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-Red Book of Vertebrates of Spain: (V) Vulnerable
-Livro Vermelho dos Vertebrados de Portugal: (VU) Vulnerable
Fishing
High commercial importance.
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Known official records of lamprey catches began in 1914. The highest value recorded by Portuguese fishermen came in 2009 with 55,930 lampreys, which corresponded to an economic value of more than €100,000.
In the Miño river there are two different areas, depending on the fishing gear used, which are subject to two different fishing periods:
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Between the group downstream of the Verdoejo Islands and the sea: January a abril. Fishing gear:lampreira
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In the Tea river they are captured with "fisga", in thelurches.
Sayings of the fishermen:
- Year of cheias, year of lampreias
- So flooded, with water from the mountain. I enria a lamprey, a agua da fonte
- A lamprey tem a boca feia
- A lampreia, in April, p'ra mim; em Maio, pr'ó anus; no S. João, p'ró cão
- Lamprey and salmon, for Easter season, after non
- March, lampreagem
- When it's mormaceira, it stings lamprey
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