Evidence and innovation hold the key to sustainable fish-farming

Aquaculture is an important and ambitious industry in Scotland, helping underpin a
successful and sustainable rural economy particularly in the Highlands and Islands.
Ensuring that this vital sector operates within the capacity of our world-class coastal
environment is essential and a key role for SEPA. One issue in particular, the control
of sea lice, continues to prove particularly challenging, but also presents an
opportunity to position Scotland at the forefront of innovation and development in
marine fish-farming.

Scotland?s ?sh-farming sector is important to a vibrant and sustainable rural economy.
Ensuring it can continue to thrive, while protecting our world class coastal environment, is a
vital consideration both for the industry and for SEPA as Scotland?s principal environmental
regulator. New evidence regarding the potential environmental impacts of treatments for sea
lice has prompted SEPA and the industry to take swift action, and tap into the sector?s
capacity for innovation, research and development, to secure a sustainable future for
Scotland?s aquaculture.

Sea lice are small marine parasites which occur naturally on many species of ?sh, but can
be a problem when large numbers of ?sh are concentrated in ?sh-farms. There are a number
of methods of controlling sea lice, including the use of authorised medicines either as a bath
or in-feed treatment such as Emamectin Benzoate.

The use of these treatments and the resulting release to the marine environment is regulated
by SEPA, and is carefully controlled by conditions included in our fish farm licences informed
by detailed modelling of the possible impacts from their use. Those conditions are set using
the best available evidence, and based on the anticipated frequency and dose of treatment,
with the aim of ensuring that the residues in the environment are within independently
derived safe environmental standards and environmental impacts are within acceptable
levels.

SEPA and the ?sh-farming sector carry out general monitoring of the overall health of the
seabed close to individual fish farms, which shows that at a small number of ?sh farms
residues from the use of Emamectin Benzoate are found to present at levels around or
above the safe environmental standard, although at this point there is little evidence
of widespread breaches of the safe environmental standard across sea lochs or voes.

While previous monitoring of seabed fauna has generally not shown signi?cant impacts on
marine animals in the wider marine environment, we have become aware of anecdotal
claims that sea louse treatments might be having an unexpected adverse environmental
impact at this scale, resulting in less biodiversity and reductions in some crustacean
populations. In response, we have undertaken a more detailed and extensive study into the
health of the seabed in the Shuna Sound, area, in which there are a number of ?sh farms
which have used in-feed sea louse treatments. This study has con?rmed a more extensive
spread within the marine environment of low levels of the residues arising from the use of
the sea louse treatment Slice, whose active ingredient is Emamectin Benzoate, than had
been expected when the medicine was ?rst authorised or had been predicted by detailed
modelling.

Since our regulatory process is based on the best available scienti?c evidence, we invited
the Scottish Aquaculture Research Forum (SARF) to commission research to further analyse
our data to determine whether there is compelling evidence of the environmental impacts
suggested by the anecdotal claims. This analysis identi?ed a subtle but detectable, and
unexpected, association between impact on the marine environment and the use of Slice.
The data is highly complex and the conclusions are not absolute but an association is clearly
indicated.

We are also aware and are concerned that in many cases the frequency and dose of Slice
treatments have regularly exceeded what was expected when the current licence framework
was developed. In most cases there is no suggestion that the treatments are breaching the
licences set by SEPA but it is possible that the fate and behaviour of the medicine once it
has been fed to ?sh differs from that which was assessed when setting the safe
environmental standard. The new treatment patterns may re?ect the fact that the treatment
is becoming less effective, probably as sea lice become more resistant to the medicine.

Where robust evidence suggests that some part of our regulatory regime is not providing the
expected and required level of environmental protection, we must take action to reduce or
remove the potential for those impacts. In this case, and following careful consideration, we
are intending to change the way in which Slice use is permitted by conditions in fish farm
licences. This will allow continued use of the medicine but subject to tighter restrictions on
use. These arrangements are likely to remain in place for a period of two years allowing the
sector or the company which markets Slice to carry out further research to con?rm or
confound the apparent link between Slice use and unexpected distribution of residues and
possible environmental effects. SEPA will also be undertaking further analysis and
monitoring work during this period. If during the next two years no compelling case is made
to support the continued use of the product, it is likely that the ability to use Slice will be
phased out completely.

We have informed ?sh farm operators of position that, unless we see new and
compelling evidence to support continued use, the ability to use Slice is likely to be phased
out in 2018. We are also working in partnership with the Industry, the Scottish Government,
the Scottish Aquaculture Innovation Centre and other key partners, to explore the potential
for the development of alternative means of controlling sea lice, which minimise the risk to
our marine environment. The challenge of controlling sea lice in ?sh farms is not unique to
Scotland, and the research and development of these alternative means represents a
significant opportunity for Scotland to establish itself as a leader in the ?eld, and could
benefit both the aquaculture sector and Scotland?s wider economy in the long run.

A new computer model, created by researchers at the Scottish Association for Marine
Science (SAMS), with support from the Scottish Government and SEPA, will become a key
tool in the future regulation of ?sh farms. This model will be available for use in applying for
?sh farm licences later this year and will enable a better understanding of how discharges
from ?sh farms affect the seabed. will replace the current 
model, which has been in use since 1999. SEPA recently launched a new survey vessel,

designed speci?cally to enhance our capability to monitor the environmental
impacts of marine fish farms.

statutory purpose is to protect and improve the environment, where possible in ways
which contribute to health and well-being and sustainable economic growth. Our approach to
working with Scotland?s aquaculture industry to help turn this environmental challenge into

an opportunity to ensure a thriving and sustainable fish-farming sector is just one example of
us putting this purpose into practice.

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