104
T. Dempster and P. Sanchez-Jerez
both EU Directives is the consideration of assimilative capacities of water bodies.
Carrying capacities of ecosystems should be modelled to estimate the acceptable
limit for aquaculture development near protected sites (see Jiang and Gibbs 2005)
for an example of such a model). Different international conventions (Convention for
the Protection of the Marine Environment of the North East Atlantic, the Helsinki
Convention for the Protection of the Marine Environment of the Baltic Sea Area and
the Barcelona Convention for the Protection of the Mediterranean Sea against
Pollution) propose good environmental management practice to limit pollution and
protect biodiversity (Davies 2001; Read and Fernandes 2003).
A precautionary approach to aquaculture in coastal areas should be considered
because of the risk of reducing biodiversity due to nutrient loading and elevated
levels of organic matter in bottom sediments and in the water column. This involves
standardising indicators of change and setting limits of acceptable modification to
environmental parameters. For biodiversity conservation of marine ecosystems, a
set of environmental quality standards should be set at the European level for the
various directives, and then adapted for regional environmental conditions. These
environmental quality standards will be a set of measurable parameters to
detect environmental impact and biodiversity change. In Norway, environmental
quality criteria for fiords and coastal waters were established in 1997 (Molvær
et al. 1997; NSF 1998). These criteria are presented within a classification system
for impacts of nutrients, organic matter, micropollutants, and fecal bacteria, and
established water quality standards for various coastal uses. At present, the ECASA
project (Ecosystem Approach for Sustainable Aquaculture, www.ecasa.org.uk), is
attempting to identify, assess and develop indicators of the impact of aquaculture
on a European-wide basis.
Monitoring programmes are necessary to ensure effective regulation and promote
adaptive management of aquaculture in coastal areas (Carroll et al. 2001). At least
seasonally, monitoring of water and sediment conditions should be routinely carried
out by fish farms to ensure compliance with the Environmental Quality Standards.
Monitoring programmes are often conducted by farmers. Where this is the case,
auditing to determine the quality of self monitoring is required, particularly with
regard to the use of regulated substances (antibiotics, disinfectants).
Effluents from fish farms can have undesirable impacts on local marine communities; these would vary depending on the quantity and composition of substances
released, the temporal scale over which the release takes place, the assimilation
capacity of the water mass and the sensitivity of the communities. The spatial distribution of fish farm installations can have substantially different effects on marine
biodiversity according to habitat type. Less complex habitats, such as seabeds
dominated by soft sediments, are well known to be affected by fish farming.
Farming of salmonids, sea bass and sea bream produces anoxic conditions due to
the increased load of organic matter, which produces hypoxia and facilitates the
growth of specialized macrofauna which are tolerant to organic enrichment (Carroll
et al. 2001; Wildish and Pohle 2005) and the proliferation of benthic microalgae on
the seabed due to the benthic flux of nutrients (Karakassis et al. 1999). Changes to
the macrofauna are marked, and include increases to the abundance of opportunistic
T. Dempster and P. Sanchez-Jerez
both EU Directives is the consideration of assimilative capacities of water bodies.
Carrying capacities of ecosystems should be modelled to estimate the acceptable
limit for aquaculture development near protected sites (see Jiang and Gibbs 2005)
for an example of such a model). Different international conventions (Convention for
the Protection of the Marine Environment of the North East Atlantic, the Helsinki
Convention for the Protection of the Marine Environment of the Baltic Sea Area and
the Barcelona Convention for the Protection of the Mediterranean Sea against
Pollution) propose good environmental management practice to limit pollution and
protect biodiversity (Davies 2001; Read and Fernandes 2003).
A precautionary approach to aquaculture in coastal areas should be considered
because of the risk of reducing biodiversity due to nutrient loading and elevated
levels of organic matter in bottom sediments and in the water column. This involves
standardising indicators of change and setting limits of acceptable modification to
environmental parameters. For biodiversity conservation of marine ecosystems, a
set of environmental quality standards should be set at the European level for the
various directives, and then adapted for regional environmental conditions. These
environmental quality standards will be a set of measurable parameters to
detect environmental impact and biodiversity change. In Norway, environmental
quality criteria for fiords and coastal waters were established in 1997 (Molvær
et al. 1997; NSF 1998). These criteria are presented within a classification system
for impacts of nutrients, organic matter, micropollutants, and fecal bacteria, and
established water quality standards for various coastal uses. At present, the ECASA
project (Ecosystem Approach for Sustainable Aquaculture, www.ecasa.org.uk), is
attempting to identify, assess and develop indicators of the impact of aquaculture
on a European-wide basis.
Monitoring programmes are necessary to ensure effective regulation and promote
adaptive management of aquaculture in coastal areas (Carroll et al. 2001). At least
seasonally, monitoring of water and sediment conditions should be routinely carried
out by fish farms to ensure compliance with the Environmental Quality Standards.
Monitoring programmes are often conducted by farmers. Where this is the case,
auditing to determine the quality of self monitoring is required, particularly with
regard to the use of regulated substances (antibiotics, disinfectants).
Effluents from fish farms can have undesirable impacts on local marine communities; these would vary depending on the quantity and composition of substances
released, the temporal scale over which the release takes place, the assimilation
capacity of the water mass and the sensitivity of the communities. The spatial distribution of fish farm installations can have substantially different effects on marine
biodiversity according to habitat type. Less complex habitats, such as seabeds
dominated by soft sediments, are well known to be affected by fish farming.
Farming of salmonids, sea bass and sea bream produces anoxic conditions due to
the increased load of organic matter, which produces hypoxia and facilitates the
growth of specialized macrofauna which are tolerant to organic enrichment (Carroll
et al. 2001; Wildish and Pohle 2005) and the proliferation of benthic microalgae on
the seabed due to the benthic flux of nutrients (Karakassis et al. 1999). Changes to
the macrofauna are marked, and include increases to the abundance of opportunistic