The biologist Miguel Clavero responds to the phone while collecting networks on the Cachón River, in Zahara de los Atunes (Cádiz). It has gone in search of eels to make a census. “If I take any warning you,” he says. But there will be no luck. What will find … In abundance they are Blue crabs. The voracious invasive species, suspected Clavero, is the last push towards the extinction of the European eel. According to his latest study, the fish is suffering a “drastic reduction” that adds to the fall recorded in the 80s, when the population collapse reached 90%, and from which the species has not yet recovered.
The European eel (‘Anguilla Anguilla’) was declared in critical danger of extinction In 2008, that is, one step away from the total disappearance. However, since then the state of the species “is seriously worsening very quickly,” according to the investigation prepared by the Doñana Biological Station (EBD-CSIC) and the Ebro Delta Natural Park. The study has analyzed only the population of the Ebro Delta and concludes that between 2015 and 2017 its presence It has been reduced by more than 80%. But researchers think it is a general trend, since it coincides with the studies data carried out in Ireland and Croatia. “And that would be the serious,” says Clavero.
Migration route
of the European eel
Anguilla distribution
Birth
At the end of winter, at sea
Of the sargazos, the eggs
They hatch in deep water
giving rise to some larvae
transparent calls
Leptocephals
These leptocephals are
carried by the currents
Oceanic to the coast
European During this trip,
They experience transformations
physical and growth.
Continental fattening
(Crystal Angula)
When the larvae reach
The European coasts,
They transform into eels
transparent. These eels
young people enter water
sweet and continue to grow and
developing, adopting
A more opaque color.
Fresh water growth
(Yellow Anguilla)
During this phase, the eels
European reside in rivers, lakes
and other river water paths
sweet. They can spend several years
or even decades at this stage,
depending on factors such as
the availability of food and
Environmental conditions.
Transformation
(Silver Anguilla)
Before migrating again to
Ocean to reproduce, the
European eels experience
A morphological transformation
and coloring. Develop
A silver coloration.
Migration to areas
of spawning
The silver eel
They undertake an arduous
migration back to sea
of the sargazos, where
originally began its cycle
life. This migration can
cover thousands of kilometers.
Reproduction and death
In the Sargazos Sea,
European eel
They reproduce and then die.
Fertilized eggs are
sink into the waters and restart
The cycle with the hatching
New leptocephalas.
European Anguilla Migration Route
Anguilla distribution
Birth
At the end of winter, in the sea of sargazos, eggs hatch in deep water giving rise to transparent larvae called Leptocephals
These leptocephalas larvae are carried by the currents
Oceanic to the European coasts. During this trip,
They experience physical and growth transformations.
Continental fattening (glass angula)
When the larvae reach the European coasts, they are
They transform transparent eels. These young eel
They enter fresh water and continue to grow and
developing, adopting a more opaque color.
Fresh water growth (yellow eel)
During this phase, European eels reside in rivers,
lakes and other freshwater river. Several years or even decades may pass at this stage, depending on factors such as food availability and environmental conditions.
Transformation (silver eel)
Before migrating again to the ocean to reproduce, the
European eels experience a morphological transformation
and coloring. They develop a silver coloration.
Migration to spawning areas
Silver eels undertake a long and arduous
migration back to the sea of sargazos, where originally
He began his life cycle. This migration can cover
thousands of kilometers.
Reproduction and death
In the sea of sargazos, European eel
They reproduce and then die. Fertilized eggs sink
In the waters and restarts the cycle with the hatching of new
Leptocefalas.
Because, with the eel, Everything is connected. «With this species there is an important concept: the European eel is a single ‘stock’. It doesn’t matter if it comes out of the delta or Norway, They come together in the Sea of Sargazos», Says Estíbaliz Díaz, representative of Spain in the group on the eels of the International Council for Sea Exploration (ICES) and Azti researcher. It is there, southeast of the US, where the eel reproduces and is born; where its life cycle ends and begins, although in between travel to Europe and North Africa to grow and mature.
He species collapse In the early 80s he was devastating. For every one hundred anguilas that arrived before the decline on the Mediterranean coasts, today they do seven. And the situation in the North Sea is even worse. There the proportion does not reach one per hundred. “The Iberian lynx and the Panda bear are better than the eel,” summarizes Díaz, who remembers that in her good times the eel came to see even in the Manzanares river, in Madrid.
Invasive species
«The two fundamental points of the decline are Habitat loss (in Spain it has lost 80%) and invasive species –They parasites that affect their mortality as new predators – ”says Clavero, to which pressures such as fishing, illegal trade or climate change are added. For the scientist it is not accidental that the drastic fall of recent years coincides with the arrival in the delta of the blue crab, A native species of the western Atlantic that is distributed from Canada to Uruguay and is explosively colonizing the Mediterranean and Norafricanas coasts, precisely where the European eel grows and matures. It is still a theory, but it would be necessary to prove it urgently because “that a crab is eaten an eel in Spain makes there less in Norway.”
Evolution of
Anguilla recruitment
(Angulas that are incorporated
to the adult population)
100% corresponds
At the average of the 1960-1979
Angula and Anguila catches
In Spain
Anguilla (yellow and silver)
Commercial landings (tons)
as notified to the CIEM by the
EU member states
EVOLUTION OF ANGUILA recruitment
(Angulas that are incorporated into the adult population)
100% corresponds to the average of the 1960-1979 years
Angula and Anguilla captures in Spain
Anguilla (yellow and silver)
Commercial landings (tons) as notified to the CIEM
by the EU member states
In addition, the eel is a long -term species on which it will not be easy to detect The real moment of extinction. “We are not going to realize,” says Clavero. The paradox could be given to be ‘functionally extinguished’, being already its unfeasible reproduction, and continuing to have copies on the coasts. “I am not afraid to say that within the next 20 years it is a probable event,” says Clavero.
No recovery
Díaz, as representative of Spain in the ICES, explains that for three years the council given by the scientific body to the European Commission is that The fishing quota is zero and that it acts on environmental and connectivity in rivers, avoiding the turns of the Hydroelectric plants. It is a “very complex” species, acknowledges the researcher, who forces to act in block and that implies many countries. For now, only Ireland and Andalusia have banned the fishing of the eel, although it has been Extended the Veda season and recreational fishing has been prohibited. However, “there are no signs of recovery,” says Díaz.
Fishermen, however, see a Restrictions Escalation. If they arrived “it would be sudden death,” says José Manuel Rosas Otero, president of the Fishermen’s Brotherhood Federation of Pontevedra, who explains that last year the fishing season was already limited to three months. In Pontevedra (Galicia) only an eels are fishing in two points, but it is an “important sector”, especially for the Angleleros of Arcade, for whom it represents the sustenance of the people. The situation, says Rosas, is incomprehensible. «It is not understood that Angula fishing, the eel fry, and get into the adult’s capture. It is a unreasonable ».
In it Mar Menor (Murcia) captures They have increased Despite the ban. If a decade ago about 12 tons of eel were collected over nine months, now in two and a half months they reach the quotas, which are 25 tons. “Why are they going to remove it?” Asks José Blaya Gómez, major pattern of the Fishermen’s brotherhood of San Pedro del Pinatar. «In catastrophic areas where there is no eel, it is worth. But we are the opposite, Every year we have moreand it is an animal that harms us because the entire fry (other species) is eaten, ”he explains.
Scientists, on the other hand, believe that adding fishing to the other pressures of the species is “unsustainable,” says Clavero. Nor do they want to see how great hope for the future of the species the possibility of getting Reproduce the European eel in captivity. Everything indicates that in the coming years it could be achieved (in fact, it has already been with the Asian) but with fish such as salmon this advance has not served to improve its state in freedom.
In any case, the future of the species is not closed. Brussels is studying asking for the regulations on international trade in the CITES agreement, which includes 185 countries. A decision on which, if taken, it would still take its implications for a while.
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