Saturday, 30 November 2013

Pesticides and salmon farms

The recent discovery of the chemical Teflubenzuron at hundreds of time the legal limit in the environment of a Marine Harvest salmon farm in Scotland highlights the dangers of releasing chemicals uncontrolled into our waters. The old attitude of ‘dilute and disperse’ has in fact wracked havoc with our environment, both in the air and in the seas.

Teflubenzuron is one of the chemicals used to try and control sea lice. These can harm and even lead to mortalities in the farmed salmon. Resistance to chemicals builds and sea lice are regularly recorded at levels where existing protocols require mandatory treatment.

In the wild, salmon return to fresh water to spawn and the lice fall off. Captive in our bays, under farm factory conditions, conditions favour the congregations of sea lice. If there are a million fish on the farm with just 1 egg–bearing louse each, the farm may release 500 million lice larvae. Even infestations at levels below which they affect the caged fish can infect wild salmon at distances of up to 30 kilometres.

Here in Ireland Marine Harvest, the Norwegian owned company that produces 80% of Irish farmed salmon, have stated that they ‘never used this medicine [Teflubenzuron] in our organic fish anywhere in Ireland, including Bantry Bay’. This, in fact, cannot be independently verified as the type, frequency of treatment, and volumes of chemicals used in any Irish salmon farm is not publicly available. The Regulatory Agency does not ‘hold’ this information and the companies (‘every stage of our production process is audited annually by independent bodies’) refuse it on grounds of commercial confidentiality.

We do however have Marine Harvest’s EIS [Environment Impact Statement] for the Bantry Bay proposed expansion. In volume 2 of 3 (Appendices) It lists Teflubenzuron on the ‘Marine Harvest Medicines Positive List‘ to treat sea lice.

Given that the Marine Harvest statement makes the point that Teflubenzuron is not used on ‘organic’ farms, let us look at two of the chemicals that are in fact approved by Marine Harvest for use on organic farms on the ‘Medicine Positive List’ in the EIS. These include Excis (cypermethrin) and AlphaMax (deltamethrin). Refered to in the EIS as ‘medicines’ or ‘chemotheruputants’, these chemicals are in fact ‘biocides’.

Medicines are a ‘drug or other preparation for the treatment or prevention of disease’. A theraputant falls within ‘that branch of medicine concerned with the remedial treatment of disease.’

Biocide is a word coined to match ‘advances’ in science in the 1940s. It is from bio (for ‘life’) and cides (a suffix for ‘the killing of the person or thing)’. Hence ‘pesticides’ and ‘insecticides’. Under the Biocides Directive, they are defined as chemicals used with the ‘intention of destroying, deterring, rendering harmless, preventing the action of, or otherwise exerting a controlling effect on, any harmful organism’. These chemicals come under the Biocides Directive as product type 18 – insecticides – but they do not appear on the Registry of Irish Biocides, as maintained by the Department of Agriculture.

They kill life; medicine saves lives. These chemicals are extremely ecotoxic active neurotoxins. Arthropods, and particularly crustaceans, are highly susceptible. There are known effects on fish and, most sensitive of all, shellfish such as lobsters. Bathers and watersports may also be at risk. For this reason, the manufacturers of both products clearly indicate that there should be no release to environment.

Even the Irish Medicines Board Information Sheets for these chemicals makes it clear that these ‘neurotoxins can only be applied to animals under specific conditions’, stating ‘Do not contaminate natural water with the product’.

In the UK horses can only be treated with cypermethrin if a veterinary certificate is supplied saying that the horse will not be used for human consumption. If the product was classed as a biocide rather than a medicine in Ireland, as it is under the Biocides Directive, its use would not be permitted unless it could be ‘scientifically demonstrated that under relevant field conditions there is no unacceptable effect’. 

According to the Galway Bay EIS (prepared by the applicant, the Government agency Bord Isca Mhara), ‘The volume of chemical used to treat a single pen of salmon [36 pens are proposed] is estimated at 3,333 cubic metres’. For comparison, an Olympic swimming pool holds 2,500 cubic metres. This will be discharged directly into the (once) natural waters of our Bays in spite of the fact that the manufactures do not support direct release of these neurotoxins.

The basic tenet of toxicology is that ‘dose makes the poison’. As the scale of emission increases, so do the risks involved. Exposure of non–target organisms is facilitated by the sheer volumes of chemicals that will be emitted.

To save money, the industry is introducing well boats. Into these floating swimming pools nets of fish, once anaesthetised (Tricaine mesilate, ‘permitted for organic fish’) are immersed in these biocides. After treatment the contents are flushed into the sea, creating massive poisonous plumes without any attempt to formalise the environmental risk assessment within the existing EU legal framework.

All with organic certification.

Tony Lowes

The Village Magazine September 2013