What is it?

Emamectin benzoate is the active ingredient in a veterinary medicine, prescribed to treat sea lice. It is a an avermectin, one of a series of drugs used to treat parasites. Emamectin benzoate is used in agricultural settings to control insects among vegetable crops such as cabbage and broccoli.

Why is it used?

It is a veterinary medicine used to treat sea lice on farmed Atlantic salmon and is administered as a in-feed treatment. Sea lice are naturally occurring ectoparasites that cause harm to wild and farmed fish. In order to keep Scottish farmed salmon healthy it is necessary to use medicines alongside a selection of alternative management measures (Figure 1).

Sea lice management measures on Scottish salmon farms

How does it work?

Mode of Action: the substance interferes with nerve impulses in the sea lice's body, resulting in paralysis and death.

How does it affect the environment?

It is rapidly eliminated and excreted by fish and is usually dispersed efficiently. The amount of time taken for it to be broken down depends on the environmental conditions (availability of oxygen, acidity, temperature etc).

How is its use controlled?

Products are produced and distributed through a safe and fully traceable supply chain. All treatments are recorded.

Medicine use is a condition on environmental licences (CAR) granted and regulated by SEPA (Scottish Environmental Protection Agency), extensive modelling and monitoring is conducted on sites regularly before and during their operation to ensure the use of medicine will not have any detrimental impact on the environment.

Releases of Emamectin benzoate are controlled through the Food and Environmental Protection Act (FEPA 1985), the Control of Pesticides Regulations (COPR 1986) and the UK Pollution, Prevention and Control (PPC) Regulations. It is also regulated through the European Directive concerned with levels of pesticide residues in foods (93/58/EC) - which in Scotland is implemented by the Maximum Levels in Crops, Foods and Feedstuffs regulations (MRL 2000).