Glossy and greedy: Bluefin tuna is one of the world's most highly prized foodstuffs
By Paul Henley
BBC News, Barcelona
"Welcome to the strange world of globalisation."
That is Roberto Mielgo's response to the fact that it is commercially viable to catch and keep live tuna in off-shore pens - or ranches - in the Spanish Mediterranean and feed them vast amounts of expensive caught fish (around 10kg of feed fish serve to make the tuna put on 1kg of body weight).
And to cull them by hand using divers, ship them to shore, package them in a purpose-built factory and fly them whole - on the same day - to market on the other side of the world.
Roberto Mielgo calls himself an independent fisheries consultant.
A former tuna rancher himself, he had a change of heart and became one of the most prominent campaigners for the preservation of bluefin tuna, one of the most highly-prized - and fought over - species and foodstuffs in the world.
The fact that the United Nations commission set up to preserve endangered species failed, at its conference in Doha this week, to put an international trade ban on this type of tuna is a bitter disappointment to him.
But, he says, it is not necessarily a surprise, given the strength of the global fishing lobby.
"The Japanese market eats 80% of all the eastern Atlantic and Mediterranean bluefin tuna that is produced," Mr Mielgo says.
"They are willing to pay the highest price. It is just normal that tuna ranches here in Europe export their very best to the other side of the world.
"There are people who are trying to manage a sound business with an environmental perspective that do abide by the rules and I have great respect for them.
"Others do not abide by the rules. It is not a question of criminalising the entire sector, but one has to see the overall problem and that is that tuna ranching is a big part of the problem. It has grown out of proportion," he said.
"If you ask me whether to save the stock or to save some jobs, my answer is pretty clear - save the stock. The stock belongs to all of us. It's not because two or three companies will have to close that I should not protect a species.
"We have been playing with fire for the past eight years, we have been overfishing the species to the brink of collapse. It has been a crazy gold-rush."
Juan Serrano disagrees.
As managing director of Balfego, a company that runs Spain's biggest tuna ranch at L'Ametlla de Mar, on the Catalan coast, he has seen profit margins dive.
Most tuna caught in the Mediterranean ends up on Japanese plates
And he is, he says, one of the "goodies" of the tuna industry.
He vehemently disputes the idea that the bluefin tuna is, in his waters at least, a threatened species.
"What we are doing is not only entirely legal," Mr Serrano says.
"It is sustainable. There is ample scientific evidence from independent sources which confirms our belief that bluefin tuna populations in the western Mediterranean are actually increasing."
Environmentalists say the average size of the individual tuna caught for Balfego's ranch is going down steadily year on year - a sign, allegedly, of a dangerous plundering of the stock.
This, again, is disputed by Mr Serrano. It is not as if the extraction of tuna from the Spanish Mediterranean is a free-for-all.
The entire national quota of tuna is caught by six boats in the single month per year they are allowed to operate.
Laid on ice
They deliver their whole catch to ranches along the Spanish coast.
The impressive size of the fish Balfego chooses to show me being harvested on the particular day I visited cannot be questioned.
Specimens of 150kg - longer than a man in length - are culled by divers with a spear-gun, hoisted on board, headed and gutted within minutes and laid in ice to preserve the valuable flesh at its best.
Tuna fillets are graded according to quality
On shore, the fish are inspected and quality-controlled in order to fetch the maximum price on a market which is supplied on demand and year-round in a way which would not be possible without the live storage facility of a ranch.
"Within this industry," says Mr Serrano, "there are good and bad operators."
"No doubt there are some that operate on the wrong side of the rules.
"What the EU needs to do is punish the bad ones, take away their licences. But we should not all be tarred with the same brush. Sustainability is vital to us, as is transparency in what we do."
There is, of course, an irony that, while fishing authorities in Brussels openly declare their support for a moratorium on bluefin fishing in the Mediterranean, their rules continue to allow tuna to be caught by boats which were constructed with the help of public subsidies and processed in factories built, similarly, with EU financial aid.
There are, undoubtedly, many in Brussels who will breathe a sigh of relief at the decision of the Doha conference.
For now, it seems, the fishing lobby has won the day.
Local authorities with the interests of the fishermen at heart are not, however, celebrating yet.
Marti Sans, in charge of the Catalan government's department of fishing in Barcelona, says the outlook for the tuna-catchers is fairly bleak.
He stresses that no public money currently subsidises their operations.
And he acknowledges that the days of net-catching tuna in the region could be numbered.
"This is our great worry," he says. "Because we know at the moment that the pressure is very strong.
"Environmental organisations have made this issue a big priority. At the moment, we are defending a type of fishing that has been been carried out well and rationally. But we have to accept that decisions are taken at higher levels which may force us into a very different situation and ultimately threaten what we do."