16
P. Tett
the loch will add to, or subtract from, these incoming concentrations. Thus it may
be as important to control nutrient levels of the Firth of Lorne as it is to restrict
enrichment within loch Creran. Indeed, we know from the results of a mathematical
model that only during the summer, when nutrients are scarce in the Firth of Lorne,
does farm input make an important contribution to Creran DAIN and phosphate
(Laurent et al. 2006).
Fortunately, the waters of the Firth of Lorne are in a largely pristine condition,
their moderate nutrient concentrations being set mainly by natural processes in
the sea to the west of Scotland. Fish farms may, of course, become sufficiently
to increase nutrients even on this larger scale. The region called the Minch,
between the Scottish mainland and the island chain of the Outer Hebrides, has a
sea area of about 10,000 km
2 . The production of 64,000 t of salmon may have
increased the concentration of DAIN and DIP in summer 1999 by a few percent
(Tett and Edwards 2002), a scarcely measureable amount. Nevertheless, concerns
about the effect of a greater enrichment may set an upper limit to the size of the
industry here.
The Mediterranean Sea, being oligotrophic, might be considered at greater
risk from enrichment, in that it takes only a little anthropogenic nutrient to double
the naturally lowconcentration in each cubic metre of seawater. However, the
Mediterranean is large; recent calculations suggest that input from fish farms will
increase the total nutrient stock of the sea by at most 1%, whereas total humandriven inputs might double it (Karakassis et al. 2005).
1.8 Regulation of Pollution and Conservation of Species
At the core of the DPSIR scheme are the links between pressures, states and
impacts. As humans became aware that the sea was neither an infinite garbage can
for wastes nor an inexhaustible source of fish (McIntyre 1995), our societies began
to legislate either to prevent pollution of the environment – corresponding to the
regulation of pressure – or to protect certain animals or plants – corresponding to
the prevention of impacts on these organisms. This was initially a piecemeal
approach, which I will illustrate for the case of Scotland with two United Kingdom
Laws – the Control of Pollution Act (COPA) of 1974, and the Wildlife and
Conservation Act of 1981 – as these have used by the Scottish Environment
Protection Agency (SEPA) to minimize the environmental impact of salmon-farming and to maintain water quality for shellfish.
My account greatly simplifies the complexities of a legal framework used to
apply these UK laws in the separate, and different, jurisdictions of each part of the
Kingdom. In most cases the generalities of the Acts of the UK Parliament (and,
since 1999, also of the Scottish Parliament) are interpreted by detailed “Regulations”
which are also commonly used to implement European Directives. Since the UK’s
accession to the European Community (as it was then called) on 1 January 1973, it
has acquired (Graham 2002),
P. Tett
the loch will add to, or subtract from, these incoming concentrations. Thus it may
be as important to control nutrient levels of the Firth of Lorne as it is to restrict
enrichment within loch Creran. Indeed, we know from the results of a mathematical
model that only during the summer, when nutrients are scarce in the Firth of Lorne,
does farm input make an important contribution to Creran DAIN and phosphate
(Laurent et al. 2006).
Fortunately, the waters of the Firth of Lorne are in a largely pristine condition,
their moderate nutrient concentrations being set mainly by natural processes in
the sea to the west of Scotland. Fish farms may, of course, become sufficiently
to increase nutrients even on this larger scale. The region called the Minch,
between the Scottish mainland and the island chain of the Outer Hebrides, has a
sea area of about 10,000 km
2 . The production of 64,000 t of salmon may have
increased the concentration of DAIN and DIP in summer 1999 by a few percent
(Tett and Edwards 2002), a scarcely measureable amount. Nevertheless, concerns
about the effect of a greater enrichment may set an upper limit to the size of the
industry here.
The Mediterranean Sea, being oligotrophic, might be considered at greater
risk from enrichment, in that it takes only a little anthropogenic nutrient to double
the naturally lowconcentration in each cubic metre of seawater. However, the
Mediterranean is large; recent calculations suggest that input from fish farms will
increase the total nutrient stock of the sea by at most 1%, whereas total humandriven inputs might double it (Karakassis et al. 2005).
1.8 Regulation of Pollution and Conservation of Species
At the core of the DPSIR scheme are the links between pressures, states and
impacts. As humans became aware that the sea was neither an infinite garbage can
for wastes nor an inexhaustible source of fish (McIntyre 1995), our societies began
to legislate either to prevent pollution of the environment – corresponding to the
regulation of pressure – or to protect certain animals or plants – corresponding to
the prevention of impacts on these organisms. This was initially a piecemeal
approach, which I will illustrate for the case of Scotland with two United Kingdom
Laws – the Control of Pollution Act (COPA) of 1974, and the Wildlife and
Conservation Act of 1981 – as these have used by the Scottish Environment
Protection Agency (SEPA) to minimize the environmental impact of salmon-farming and to maintain water quality for shellfish.
My account greatly simplifies the complexities of a legal framework used to
apply these UK laws in the separate, and different, jurisdictions of each part of the
Kingdom. In most cases the generalities of the Acts of the UK Parliament (and,
since 1999, also of the Scottish Parliament) are interpreted by detailed “Regulations”
which are also commonly used to implement European Directives. Since the UK’s
accession to the European Community (as it was then called) on 1 January 1973, it
has acquired (Graham 2002),