All of Malta’s five tuna farms have been fined for the occurrence of so-called ‘slime’ and other breaches of permit conditions over the past two months, The Sunday Times of Malta has learnt.

The Environment and Resources Authority (ERA) has been imposing daily fines on the farms.

For two months running, members of the ERA’s enforcement directorate have been conducting inspections on the fish farms on alternate days, covering north and then the south. On some days all farms were examined in a blitz of inspections.

Some of the farms have since come into line with environmental legislation while others are cooperating with the ERA to move towards compliance. Fines of up to €70 daily are lifted as soon as compliance is achieved.

Tuna ranches are regulated by three operational permits from the Planning Authority, the Department of Fisheries and Aquaculture, and the ERA. The ERA permit sets out detailed conditions over 20 pages long, and all the tuna ranches have been found in breach of the permit conditions since mid-July.

Tuna farming – or ‘ranching’, as it is internationally known – has been in the news after the industry was blamed as the source of patches of floating ‘slime’ washing up along the coast throughout the summer.

This prompted the newly formed enforcement directorate within the ERA to mount the ongoing enforcement operation, and for the industry to separately respond with a media charm offensive.

When the frozen mackerel is thrown into the warm summery water, it quickly starts to decompose

In a series of statements and site tours for reporters, the Federation of Maltese Aquaculture Producers (FMAP), which brings together four of the tuna ranches, has attempted to take the initiative by talking of self-regulation mostly tied to a raft of preventive measures put into effect since last month.

Charlon Gouder, executive head of FMAP, wrote in reply to questions that the ranches are exploring “methods of best practice to reduce leakage of waste”. He specified that “four of the farms signed a self-regulatory agreement to regularise their procedures with mid- to short-term solutions, including the use of booms, boats and other physical methods to ensure that any negative impacts on the environment are kept to a minimum.

“We are presently also looking at a long-term solution strategy that will eliminate leakage altogether,” wrote Dr Gouder.

He added that an independent inspector has been appointed by the federation at the expense of the operators to monitor and report back on the process and “the capturing of any oil material from within the cages”.

The director of enforcement at the ERA, Mario Schembri, told The Sunday Times of Malta that “the federation [FMAP] is giving the impression that they are taking these measures on their own initiative, but preventive measures are an obligation laid down in the permit issued by the ERA”.

Meanwhile, fishermen’s accounts kept coming in over the past two weeks. Calamari fishermen spoke of slime sticking to their line and making it slippery, another fisherman of nets getting soiled, and a sender of videos and pictures described “a nasty smell of fish oil and the sea littered with this floating mess”.

Containing the ‘slime’

The patches of so-called ‘slime’ are formed when oily detritus of whole mackerel and herring fed to the tuna is washed out of the floating tuna pens, and then purportedly mixes with other unrelated, non-tuna-ranching effluent floating in the sea and coagulates into viscous, foamy floating patches that are unsightly, smelly, and slimy.

The oily detritus is denser and filthier when the tuna are fed imported frozen fishes, according to sources in the fisheries department. Tuna are partly fed locally-caught fresh mackerel but mostly imported frozen mackerel and herring.

“When the frozen mackerel is thrown into the warm summery water,” a government official who wished to remain anonymous said, “it quickly starts to decompose. So the department and tuna farms have been exploring ways to minimise the effluent in the first place by, for example, thawing the frozen mackerel on shore before throwing into the tuna pens at sea.”

In the meantime, a range of immediate containment measures have been put in place in the past two months.

These include surrounding the pens with booms to contain and skim out the oily detritus that forms on the surface during mealtime, and putting a boat on standby to skim out any patches that leak out of the booms. (The FMAP has also been claiming that its members are collecting and exporting the oily remains for various uses, such as biofuels and other possible industrial uses.)

“The incidence of slime has decreased in the past two months since we have been carrying out inspections,” said Mr Schembri of the ERA.

“I don’t think it can be fully eliminated even if any floating emulsion of oil is all skimmed up because some remains sink through the meshes of the cages and then float up some distance away. But if all the preventive measures are put into place, then I think much more than half of the problem can be solved.”

The slime, Mr Schembri pointed out, isn’t damaging to health or the environment as such, it’s just repulsive.

Fishermen have spoken of slime sticking to nets and fishing gear in the region where tuna farms are situated. Its fecundity in the summer, when bathers descend on Malta’s eastern seaboard and near-shore fishing is widespread, makes it particularly troublesome.

A fisherman who spoke on condition of anonymity said that he estimates that less than half of the slime problem has been solved by the recent measures.

Wild Bluefin tuna are caught in early summer as they migrate to the Medi­terranean to spawn. They are corralled in tuna pens for feeding and fattening till autumn, then slaughtered and ship­ped mostly to Japan, where the Bluefin is highly sought for sushi and sashimi.

Tuna farming industry: facts & figures

Malta top for capacity

Wild Bluefin tuna are caught in early summer as they migrate to the Medi­terranean to spawn. They are corralled in tuna pens for feeding and fattening till autumn, then slaughtered and ship­ped mostly to Japan, where the Bluefin is highly sought for sushi and sashimi.

The point of ‘fattening’, besides increasing weight, is to ‘produce’ the kind of flesh favoured in Japan for its  desired elevated fat or oil content. Bluefin tuna is known as ‘black gold’ in Japan, and Japanese are willing to pay for the privilege of eating it: the two Malta-produced tunas auctioned in Tokyo’s fish market during the visit by Prime Minister Joseph Muscat and  FMAP officials on August 1 was re­por­ted to have fetched €35 per kilo (about three times the price at fishmongers of in-season tuna in Malta).

Malta’s tuna ranching industry is now said to be worth over €120 million (the entire aquaculture industry is worth about €128m), and tuna is one of Malta’s chief export commodities. The island, in fact, has the highest capacity of tuna farming in the world at 12,300 tons (this excludes 1,500 tons of idle capacity currently registered to the Fisheries Department). The country with the second highest capacity is Spain, with 11,875 tons, followed by Italy at 9,500 tons.

The environmental implications of a higher density of tuna farms in Malta than anywhere else – the coastlines of Spain or Italy are much longer and they have less tuna ranching capacity – have not been specifically or holistically studied. In theory, the density of farms in proportion to length of coastline may make slime or other effluent more prevalent, but it’s not known whether this will remain pertinent given the current mitigation measures.

“Under the Water Framework Directive we have to report to the EU on our water quality, but I don’t know what the reports say,” fisheries expert Alicia Said told The Sunday Times of Malta.

“I have to say that there is an element of hyperbole in coverage or discourse about the sea slime. But the problem is that if someone takes a video and it goes viral online, it damages tourism. And tourism employs many more people than aquaculture.”

Sustainability, growth

Aside from the patches of ‘slime’ – which is disgusting to humans and can stick to fishing gear but is reportedly not harmful to the environment – the environmental sustainability and social ethicality of tuna ranching has long been questioned because of overfishing and low feed conversion ratio.

After teetering on the brink of extinction a decade ago, the tuna population has recovered in recent years after a con­ser­vation plan imposed by the In­ternational Commission for the Conservation of Atlantic Tunas. Fishing quotas are on the rise again, and there is now talk of expanding fishing and ranching industries around the Mediterranean.

FMAP CEO Charlon Gouder said: “The federation, whilst committed to further growth, understands that this has to be done in full respect to the environment and the public.”

Asked specifically if tuna ranching is environmentally sustainable, Dr Gou­der said: “Yes, 100 per cent. In 2014, the government had formulated a strategy on aquaculture, we want to stick to that strategy because it was forward-looking and we want to contribute to an industry that’s more sustainable.”

Malta’s tuna ranching industry is worth over €120m

The 2014-2025 Strategy on Aquaculture is a generic document with broad, overlapping, even jarring, principles and objectives. One is to “maintain current levels” of tuna ranching. Elsewhere, the document states that “further expansion [of aquaculture] will be considered in Aquaculture Zones where the environmental carrying ca­pa­city allows,” and that “future farms for capture based species [tuna ranching] will need to be sited at water depths of 50 metres or more within areas identified as Aquaculture Zones.”

No holistic carrying capacity studies have been conducted in Malta. Each application is assessed for environmental impact on its own merits, al­though monitoring of each farm can also provide a larger picture of overall impact at the Aquaculture Zones.

“Sustainability consists of many con­cepts,” Dr Said explained. “Issues of water quality, interaction with other fisheries, feed conversion ratio – in tuna fattening it’s using one protein to convert it into another and there is an element of wastage because of the low conversion ratio.”

The UN Food and Agricultural Organisation reports that the feed conversion ratio of Bluefin tuna in pens during fattening can range from 15 to one to 40 to one, depending on the weight at capture (“large tunas do not increase mass as much as they in­crease the fat content”). In this range a tuna has to consume anywhere bet­ween 15kg and 40kg of fish, mostly mackerel and herring, to gain one kilo of weight.

In a paper in the British Journal for Agrarian Change, Stefano Longo and Brett Clark wrote: “The metabolism of Bluefin tuna requires high inputs of energy (calories) to increase body size and weight. The food conversion ratio is at least 20:1 or as high as 30:1, which translates into a net loss of energy during this production process.”

In this scenario, taking into account various studies, including a growth trial conducted in Malta in 2010, it can be extrapolated that a typical 60kg ranch­ed tuna would have to consume several hundred kilos of edible fishes to gain a couple of dozen kilos in weight. 

Tuna in Malta’s farms is mostly fed imported mackerel and herring as well as mackerel and sardines caught lo­cally by fishery known as tal-lampara, which consists of 13 vessels. Mackerel has largely fallen out of favour with consumers, making tal-lampara fishery largely reliant on tuna ranches.

“It’s a buyer’s market,” one fisherman told The Sunday Times of Malta. “The tuna farms control our fishery.”

“Tal-lampara fishermen get around 50c per kilo to sell mackerel to tuna farms,” said Dr Said. “The fishers say they have to catch certain quantities to make their fishery viable, that those quantities would be less if they were paid more. There is no issue with mackerel overfishing at present, but any expansion of tuna farming in future may have an effect on lampara fishery.

“So we cannot look at the tuna fishery in isolation, it’s linked to other fisheries, and sustainability has to take into account these things too.”