Science - October 8, 2009

Eels in danger

A parliamentary debate on 10 September led to a fishing ban on eels from September through November. Fishermen don't like it. But scientists insist that this is the species' last chance.

Eels are dying out. And with them dies not just a unique fish and a prized delicacy, but also a bit of Dutch culture. No Dutch fair is complete without smoked eels, and eel fishing towns such as Volendam and Urk would lose a bit of their identity if they lost their age-old icon. But politicians have taken action at last, after brushing off the warnings of experts for many years. A fishing ban in the months of September, November and December is a last-ditch attempt to save the eel. Minister of LNV Gerda Verburg pushed through the ban in the face of resistance from some parties, and to the annoyance of the fishing lobby whose alternative plan to put over 150 tons of eels in the sea was brushed aside. 
A low point
The decline of the eel started very gradually over half a century ago, and went unnoticed at first. When the migration of young glass eels from the sea shrank by over ninety percent in the nineteen eighties, it became clear that something was very wrong.  And it didn't get better. Researchers from IMARES have been sounding the alarm about the eel in reports and presentations for years. To no avail, as government refused to take action. But as they said in one of their reports, something had to give. Sadly, it seems they were right. The eel population has gone down by three quarters in sixty years, and there's very little chance of a recovery at the moment as the number of glass eels coming into the Netherlands is also at an all-time low: only one percent of what it was in the nineteen eighties. And in Southern Europe, where ninety five percent of European eels migrate up rivers, numbers have dwindled to next to nothing.
Although it is not clear exactly why the eel population is in free fall, it is clear that something must be done before the species is wiped out. Minister Verburg has decided to stop eel fishing this October and November and from 2010 from September through November. This is the period in which the adult silver eels head for the sea. So the fishing ban should enable more eels to reach the spawning grounds.
Not enough
Carel Drijver, head of the Oceans and Coasts Programme at the Worldwide fund for nature (WWF) is pleased that steps are being taken, but eventually wants to see a total eel fishing ban. 'Seventy percent of the eel deaths in the Netherlands, about 900 tons, can be put down to fishing, according to an IMARES report', he says. 'A ban is the most effective way to try to save the eel, and eventually the eel fishing industry will have to be closed down.' Drijver is afraid that in spite of firm measures, the recovery of the species will take decades because fishing has gone on far too long in the face of dwindling stocks. 'Government is ten years too late with good management measures.'
Unequal treatment
Johan Nooitgedagt, chair of the Dutch fishermen's union, admits that the eel is in a sorry state, and that it is very late in the day. Nooitgedagt: 'Sadly, the patient has been in intensive care for far too long already.' And yet the fishermen are unhappy about the minister's proposal. Nooitgedagt is particularly dissatisfied with the role of Brussels in the eel story. 'I think it would have been much better if, a couple of years ago, no one in Europe had been allowed to catch eel, including glass eels', he says. 'Be a man, have the guts to stand up for the policy. Then everyone's in the same boat.'  Nootgedagt would much rather have seen a good redeployment scheme, with fishermen being bought out. He also things that the Council of fisheries ministers should never have agreed to such a far-reaching measure without making a compensation plan for the fisherman. He is not convinced that other EU countries are going to follow suit: 'The Dutch fishermen are the victims of very unequal treatment.' He also finds it inexplicable that glass eel fishing is allowed to continue in Southern Europe, especially in Spain and France. Over ninety five percent of the young glass eels end up in France and Spain, where they are fished on a vast scale for use in haute cuisine or sale to eel nurseries. Including the Dutch eel nurseries that are a major driving force in the glass eel fishing industry.
Recovery programme
Drijver recognizes that overfishing of glass eels is a big problem, and thinks that it too should be stopped immediately. But he denies that there has been any unequal treatment of Dutch fishermen. He explains: 'Ireland has stopped all eel fishing, and Norway, Scotland, Germany and Denmark have imposed restrictions on it, or are planning further restrictions for the near future.' The fishermen's proposal to throw 157 tons of migrating eels over the dyke into the sea is out of the question now the fishing ban is in place. Neither Brussels nor the ICES thought it was adequate. 'Quite right', says Drijver. 'For a start, we have no idea whether those eels would survive. And anyway, 157 tons is peanuts compared with the 4000 to 6000 tons of adult eels that are needed per year for the species to recover.' But there is still hope for the fishermen. Even with a total ban in place, Drijver envisages a key role for this dwindling professional species. 'We mustn't let the knowledge of professional fishermen get lost', he says. 'The WWF would like to see governments and nature managers working on recovery programmes for eels together with the eel fishermen. They could play a role in the management of inland waterways.'
The sex life of eels
The age-old mystery of where eels come from has fascinated people since Aristotle's time. He thought they emerged from the mud. The eel lives most of its life in coastal or inland waters, but migrates to the open sea to breed, after which it dies. So the eel only reproduces once. Its trek is shrouded in secrecy, as nobody knows for sure where the eels go to. Some think they hold their huge orgy in the Sargasso sea when they are between the ages of ten and twenty. And they have to be pretty dedicated to joining in the ultimate group sex event: they swim about five thousand kilometres without food. It takes them six months, during which time they live on their fat reserves. But there's no hard evidence for the Sargasso scenario, as no adults eels or eggs have been spotted there, only larvae.
'Save the eel'... but how?
Because so little is known about the reason for the eel's decline, there is no guarantee that the planned measures to save it will work. But doing nothing is not an option. To maximize the chances of recovery, action must be taken on several fronts at once, say researchers from IMARES, Vivion and Vis. For a start, the eel's habitat must be improved, so it has fewer natural enemies and competitors, and cleaner water. Then there must be enough glass eels coming inland, and the number of eels reaching the spawning grounds needs to go up dramatically. According to an IMARES report, a sustainable eel industry requires fifteen times as many adult eels to reach the sea than the 400 tons that manage at present. So reducing fishing is an unavoidable step. But by itself, a fishing ban is not enough and could even be counterproductive: If eel fishing stops there is no political motive to protect the species. This makes fishing quotas handier that a total ban, say some researchers. And you need to provide glass eels and adult eels with safe passage past locks, weirs and dams.
P.S. Hard to breed
It's not just a mystery where eels do it, but also how they do it. They seem to find it very hard to breed in captivity. And that is why eel nurseries are 100 percent dependent on wild glass eel catches, more than half of which go to nurseries. Not too sustainable, then. Johan Verreth of the Aquaculture chair group is involved in an EU project in which various research groups are trying to solve the mystery of eel reproduction. Wageningen will focus on improved feeds for the mother eels so that they can produce strong healthy young. 'The problem with eels is that the eggs ripen extremely slowly', explains Verreth. 'In Japan they have managed to get Japanese eels breeding a little bit in captivity by giving them weekly hormone injections. It's very stressful, but there is no alternative yet.' 


P.S. Why the decline?
The dramatic and mysterious decline of the eel in Europe is the subject of much speculation among experts. Most scientists put it down to a combination of factors, and do not lay all the blame at the door of the fishing industry. Weirs, dams and floodgates are also bad news for eels: they only get past them in the form of eel soup. Viruses, parasites and pollution with dioxins and PCBs can also play a role. Chemical pollutants collect in the eels' fat. When they start migrating to the spawning ground, their fat reserves are activated, and with them the stored chemicals, which can set off various hormonal processes. Changes in the climate and in the ocean could also affect the eel.

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