Last week we had a look about the aspects related to the sustainability of tuna penning. This week we shall try to find out how the fish themselves are affected, what risks are being taken while tuna penning and other related hazards that we may know of.
Aerial photo of a typical floating open-pen net system
First of all we must realize that the tuna pens are not all that large and the number of tunas kept in this confined space is considerable. To say the least, the tuna have very limited space to maneuver and swim around. Apart from the fact that the tuna itself is in a way ‘imprisoned’ in a confined volume of water, the over population per cubic meter of water presents a number of problems.
Results of the use of pesticides and chemicals
One acknowledged problem is the higher risks of disease. In a confined space the disease spreads quicker and as the population is dense it affects almost all the tuna in the pens. Once a disease is detected the owners will have to use antibiotics and other chemicals and it is not the first case that it will be cheaper for the owners to either destroy all their stock or ‘arrange’ for an accidental escape. This has happened all over the world with salmon and other types of fish farming, so it could just as well happen with tuna.
Once tuna do escape, whether accidentally or not the amount of fish will unbalance the nature of the wild fish in the area and it has other negative effects on other wild fish. Tuna wants to eat and thus they will destroy an abnormal amount of wild fish in the region.
Bacterial mat (aquamanure), caused by excessive waste deposition, indicating seriously degraded conditions under a farm
The amount of food that tuna are fed every day to force them to increase in their weight and improve their growth is a very large amount. In a pen we may consider that tons of food is fed regularly throughout the process. The fact that during the complete cycle of tuna farming, the tuna itself only increase by less than 20% of its original weight, it goes without saying that a considerable amount of food is not consumed and thus is deposited under or nearby the pens.
Another point is that as the fish do not add up in weight in relation to the amount of food given, it appears that the tuna itself will pass away a lot of digested food in terms of ‘sewage type’ waste better known as 'aquamanure'.
In Scotland, the Friends of the Earth claims that the sewage waste generated by the salmon farms is double that generated by the whole population in Scotland. The above two forms of waste will one way or another have some negative effect on the pollution of the waters nearby, which may result in damage to the local sea living environment and water pollution.
It has been said that tuna penning attracts some types of sharks. Whether this is true or not, is not yet proven, but as we have seen their will be a reasonable amount of unconsumed food in the nearby area and thus one expects that all types of wild fish are attracted to the area for the ease of feeding themselves.
With salmon farming it is normal practice to use various chemicals to improve the growth rate and also to maintain the best pinkish color. As far as I can find there is no indication that similar methods are used with tuna penning although if chemicals are used either for growth, quality or medicinals, it will be very difficult to find out especially with type of monitoring that the laws enforce. It appears that in most countries, and surely in Malta, the monitoring tasks are entrusted to third parties who are on private business concern and the States Authorities have no means and ways to crosscheck their reports as the State itself do very little monitoring if any.
Dead seal found on Quadra Island, near several fish farms, November 2000. Large holes appear to be from bullets
Most of these problems are found in all the parts of the world, including the most advanced countries. Even reports from Canada indicates problems with lack of control and accountability as far as fish farms, mainly salmon, are concerned. In some countries the NGOs declare that the Environmental Impact assessments studies commissioned by the Planning Authorities are a farce in themselves as the private company who undertakes the studies appears to be more inclined to support the development rather than drawing the complete picture. This is mainly due to the fact that the EIA Studies has to be commissioned by the Developer himself as the States do not commission the studies or use their own resources to do them. So, these problems are similar to what one suspect that goes on even in Malta in similar cases. We just hope that this is not the case.
In my opinion there are a lot more planning blunders going around other than tuna penning plans to place them all at one particular area, because I believe that tuna penning will only be with us for a couple of decades or so, as by time it will not continue to be a business speculation attraction.
Source: Written by Major Tony Abela, Malta Star
