1 Fish Farm Wastes in the Ecosystem
43
mostly from several sources. For each, one or more a pressure-impact diagrams can
be drawn. Models, such as those examined during ECASA, can be used to guide
management of the pressures. Monitoring can be carried out to establish whether
impacts within Creran remain within the “safe” region in each pressure-impact diagram. If they do, then human use of loch Creran is sustainable, and we can expect
to go on using it in the same way in future as we have in the past.
Of course, this judgement is not eternal. Changes such as those due to global
warming, for example, might increase or decrease the loch’s assimilative capacity.
In a warmer world, in which water can dissolve less oxygen, the oxygen demand of
decaying waste might be more critical than the nutrients released by that decay. So
the situation must be kept under review.
It is also possible that the ecosystem approach might be used not only to maintain the health of loch Creran but also to increase the efficiency with which humans
can take goods (such as mussels) and services (such as nutrient assimilation) from
it. Suppose, for example, that the critical pressure-impact diagram is the one that
relates eutrophication impact to nutrient loading. This could constrain finfish-farming by means of setting a limit to the amount of nutrients that the farm could put
into the water. In this case, farming shellfish or seaweeds in the loch might be a way
of removing some of these nutrients and hence effectively increasing the nutrient
assimilative capacity of Creran.
My other theme in this chapter has been the potential impact of the Water
Framework Directive on fish farming. The Directive aims to establish a framework
that protects and enhances the status of aquatic ecosystems, and that is – excepting
my reservation about the difference between ecosystem health and ecosystem
quality status – just what is needed to maintain health and ensure ecological sustainability. How much difference will the WFD make to aquaculture? As in many
places in this chapter, I focus on Scotland, the only part of Europe where I am
familiar with law and regulatory practice as well as the ecological impact of fishfarming. For Scotland there are two simple and apparently opposed answers: not
much; and, a lot.
First, the “not much change” answer. Because the WFD builds on and synthesizes previous directives, and is implemented in Scotland using regulatory methods
that are already well developed, the changes in regulation are likely to be gradual
and, perhaps, will impact most on the most old-fashioned aspect – that of pollution
by synthetic compounds. In my view, fish farmers should expect in the long run to
do without these, which has implications for the management of fouling, sea-lice
and diseases. It probably means farming fish at lower densities in more highly dispersive environments. However, some fish farmers are already exploring this, and
those that do so are able to get a premium on their fish, both out of consumers’
concern for animal welfare and environmental health, and because (in my view)
fish thus farmed, taste better.
Second, the “big difference” answer. This is based on the argument that the
WFD implements the ecosystem approach. If farmers and regulators become real
converts to the ecosystem approach, their world view will change. Farmers will go
from reluctantly conforming to AZE regulations to willingly embracing their part
43
mostly from several sources. For each, one or more a pressure-impact diagrams can
be drawn. Models, such as those examined during ECASA, can be used to guide
management of the pressures. Monitoring can be carried out to establish whether
impacts within Creran remain within the “safe” region in each pressure-impact diagram. If they do, then human use of loch Creran is sustainable, and we can expect
to go on using it in the same way in future as we have in the past.
Of course, this judgement is not eternal. Changes such as those due to global
warming, for example, might increase or decrease the loch’s assimilative capacity.
In a warmer world, in which water can dissolve less oxygen, the oxygen demand of
decaying waste might be more critical than the nutrients released by that decay. So
the situation must be kept under review.
It is also possible that the ecosystem approach might be used not only to maintain the health of loch Creran but also to increase the efficiency with which humans
can take goods (such as mussels) and services (such as nutrient assimilation) from
it. Suppose, for example, that the critical pressure-impact diagram is the one that
relates eutrophication impact to nutrient loading. This could constrain finfish-farming by means of setting a limit to the amount of nutrients that the farm could put
into the water. In this case, farming shellfish or seaweeds in the loch might be a way
of removing some of these nutrients and hence effectively increasing the nutrient
assimilative capacity of Creran.
My other theme in this chapter has been the potential impact of the Water
Framework Directive on fish farming. The Directive aims to establish a framework
that protects and enhances the status of aquatic ecosystems, and that is – excepting
my reservation about the difference between ecosystem health and ecosystem
quality status – just what is needed to maintain health and ensure ecological sustainability. How much difference will the WFD make to aquaculture? As in many
places in this chapter, I focus on Scotland, the only part of Europe where I am
familiar with law and regulatory practice as well as the ecological impact of fishfarming. For Scotland there are two simple and apparently opposed answers: not
much; and, a lot.
First, the “not much change” answer. Because the WFD builds on and synthesizes previous directives, and is implemented in Scotland using regulatory methods
that are already well developed, the changes in regulation are likely to be gradual
and, perhaps, will impact most on the most old-fashioned aspect – that of pollution
by synthetic compounds. In my view, fish farmers should expect in the long run to
do without these, which has implications for the management of fouling, sea-lice
and diseases. It probably means farming fish at lower densities in more highly dispersive environments. However, some fish farmers are already exploring this, and
those that do so are able to get a premium on their fish, both out of consumers’
concern for animal welfare and environmental health, and because (in my view)
fish thus farmed, taste better.
Second, the “big difference” answer. This is based on the argument that the
WFD implements the ecosystem approach. If farmers and regulators become real
converts to the ecosystem approach, their world view will change. Farmers will go
from reluctantly conforming to AZE regulations to willingly embracing their part