A study strongly confirms the levels of aquaculture pesticides used to kill sea lice in fish farms exceed standards set to protect the environment in places such as Bantry Bay.
Researchers took samples of water, sea bed sediment and various marine organisms near Norwegian fish farms.
The samples were tested by researchers for an environmental research organisation, Norwegian Institute for Water Research, on some of the commonly used fish farm pesticides — such as diflubenzuron, teflubenzuron, emamectin benzoate, cypermethrin, and delta-methrin.
As Norway has no environmental quality standards (EQS) system, the data was compared to the thresholds set in the UK.
In many cases, concentrations exceeded the British standards set, highlighting use of the sea lice treatments was posing a threat to the environment.
For teflubenzuron in sediment, the EQS was exceeded in 67% of the samples; and levels of diflubenzuron in water exceeded the EQS in 40% of samples collected.
Researchers also note that: “A crude assessment of the concentrations detected in the shrimp collected from one location and the levels at which chronic effects are seen in shrimp would suggest that there is a potential risk to shrimp. It would also be reasonable to extrapolate this to any species that undergoes moulting during its life cycle.”
Alec O’Donovan, secretary of Save Bantry Bay — an organisation opposed to a massive fish farm in the region — said the researchers’ warnings should be heeded.
“The value of shellfish landed in Bantry Bay was €646,590 in 2009, and the industry continues to support a number of local jobs,” said Mr O’Donovan.
“It is ludicrous to put this at risk by adding more salmon farms and greater pesticide emissions that have the potential to wipe out stocks.”
With one of the world’s biggest fish farm companies Marine Harvest planning to develop a new facility at Shot Head in Bantry Bay, Mr O’Donovan said: “This could result in a significant loss of jobs, given 30 fishermen also currently work Bantry Bay for crustaceans such as shrimp, prawns, lobster and crab.
“The Shot Head salmon farm, in the meantime, would only create two full-time positions.
“We fully back the researchers call for international quality standards to be drawn up. Irish environmental quality standards, differ from those in the UK. The standard set for teflubenzuron allows five times the residual quantity in our waters, and we have no standard at all for diflubenzuron.
“These were the two most problematic pesticides in this study and both are authorised for use in Irish salmon farms. But, to make matters worse, to date the Department of Agriculture has refused to release data on emissions of these pesticides in Irish salmon farms. ”