CLOSED : Proposal to introduce a licensing regime for a sea
lice medicine based upon deltamethrin under the Water Environment
(Controlled Activities) (Scotland) Regulations 2005
Summary
The Scottish Environment
Protection Agency (SEPA) is seeking views on a proposal to
introduce a method for licensing a new sea lice medicine based on
the active ingredient “deltamethrin”. The product has been sold for
a number of years in Norway under the brand name “Alphamax”.
Sea lice are a common problem in marine cage fish farms where
these small parasitic crustaceans attach themselves to the skin of
the salmon and feed off the fish’s blood. Fish farmers use various
medicines to deal with the lice some of which are administered by
enclosing the fish cage in a tarpaulin and adding to the water in
which the fish swim, others via the food fed to the fish. The new
product will be administered by enclosing the fish cage and adding
to the enclosed water.
The product is designed to kill small crustaceans and therefore
potentially poses a risk to other types of marine creature. In
order to protect non-target animals, SEPA requires that fish
farmers apply for a licence to allow the release of the medicine
following use. SEPA places strict, site-specific, limits in the
licence on the amount of the substance that can be used at any
given fish farm site.
It is intended that the limits will be set to ensure that
outwith the immediate vicinity of the fish cages, the concentration
of deltamethrin does not exceed a safe level known as an
Environmental Quality Standard (EQS). This EQS is derived from
toxicity data for a wide range of animals and plants and includes a
significant safety factor to ensure that all species outwith the
immediate vicinity of the cages are not endangered by the use and
discharge of the product. The limits are set using computer models
which calculate how the medicine spreads, and is diluted as it
leaves the fish farm. For deltamethrin, SEPA has set a standard of
6ng/l and SEPA will limit the amount of medicine that can be used
to ensure that the concentration of residues does not exceed this
standard 6 hours after release from the fish cages.
The new product is chemically very similar to an existing
medicine “Excis” based upon the active ingredient cypermethrin. The
similarity between the products means that SEPA intends to use the
same computer models to set licence limits and at sites where the
use of Excis is permitted, SEPA does not intend to advertise
application for a licence to use deltamethrin. Where a licence for
the use of deltamethrin is sought and Excis is not already
licensed, SEPA will advertise the application in the normal way, as
set out in the above regulations.
Fuller details of the proposals are set out in the formal
consultation document.
Please Note: This consultation
CLOSED on 19th May 2008