New tuna pen spotted off St Paul's Island. (Photo: Stop the Slime environment group)
Fish slime effects on health raise concerns
Thursday, September 13, 2018, 23:10 (GMT + 9)
During the public consultation process carried out on the application for an expansion in the number of tuna pens, concerns about the effects of fish farm slime on health and the environment have been raised.
These concerns were expressed by Stop the Slime campaign representative Nicolai Abela, who said that research carried out by government entities in 2016 showed that the slime - which, in cases where it has reached the shoreline, has been the subject of numerous complaints by the public due to its foul smell. In addition, it is considered an imminent threat to the environment, including to marine life along the coastline, and also has an effect on human health, Malta Today reported.
In January this year, Azzopardi Fisheries filed an application to double the number of tuna cages, in the Sikka l-Bajda area, from 12 to 24, bringing the total biomass within them to 3,300 tonnes of fish. The total biomass would be kept by Azzopardi Fisheries and Malta Mariculture Limited (MML).
The area in question, five kilometres off the coastline, is ecologically protected, with an Environmental Impact Assessment (EIA) carried out earlier this summer having suggested that proper management may reduce the negative impact of a tuna cage extension.
An application submitted to the Planning Authority for four tuna pens to be relocated to Is-Sikka l-Bajda, in St Paul's Bay from their former location in the south of the Comino channel. A local Facebook community called Stop The Slime has launched an appeal on social media asking the Maltese public to object against the relocation.
Regarding the health risks, Abela said that he had had “reports from several dermatologists who confirmed that if contact is made with the slime, it should be removed as soon as possible with soap, as it can cause skin irritation and even boils”.
“From my experience, it’s very hard to remove. This health risk seemed to not have been included in the EIA – people are coming in contact with the fish slime,” he said.
Responding to Abela’s concerns, marine ecologist Adrian Mallia, representing the consultancy firm which carried out the EIA, said, however, that no formal studies had been carried out about any possible environmental or health effects of fish slime.
“It hasn’t yet been studied what the environmental impact of the oils is, but being a natural product, it is unlikely it would have such an effect,” Mallia said, “The focus now should be on ensuring good practices on these farms, in order to contain the impact within them.”
Arguments were also raised regarding why the tuna cages were located in a protected area, with the Environmental Resources Authority (ERA) responding that the fact that a tract of sea is protected, did not mean no development could take place there, as long as an assessment determines that the impacts would not be significant.
Others asked why the tuna pens were located only 5km offshore, and not further out, with Mallia asserting that currently technological limitations might not make it possible to move too far out to sea.
Mallia emphasised that the application proposal is not to increase the fish biomass in the pens, but to lower the stocking density by having more cages. "The biomass will not exceed a maximum of 3,300 tonnes, which is the limit allowed now" he said.
Regarding the bait fish feed given to the tuna – the source behind the smelly slime – Mallia said over 94 per cent of the 5.5 tonnes of fish given to each cage, every day, was ingested by the tuna, with 5 per cent being lost as fish oil.
Around seven cubic metres of fish oil would be released each day per cage into the open sea, according to a model for the 24 cages, Mallia said.
The trajectory of this – whether it reaches the coast or not – would vary widely according to the prevailing winds. However, he said, the scenarios in the models were very complex, their outputs were not absolute, and they were mostly useful for comparisons.