48
M. Holmer et al.
range of impacts from aesthetic to direct pollution problems (Fig. 2.1, Pillay 2004).
Fish production can generate considerable amounts of dissolved effluents, which
potentially affect water quality in the vicinity of the farms, and due to rapid dilution, also at larger scales (km-scale). Due to the rapid dilution it has been difficult
to document the effects of dissolved nutrients in farm vicinities, in particular in
areas with relatively high nutrient concentrations such as in the Baltic Sea
(Christensen et al. 2000). Other studies of fishery landings in the Mediterranean
suggest that nutrients are rapidly transferred up the trophic chain enhancing secondary production (Machias et al. 2005), indicating that monitoring of nutrient losses
should be done at different scales. Due to rapid settling of feed and faecal pellets in
the vicinity of the farms, benthic impacts are much more widely documented
(Holmer et al. 2005; Kalantzi and Karakassis, 2006). This input of organic rich
material enhances the microbial processes in the sediments, often leading to anoxic
conditions (Holmer and Kristensen 1992). This may have major effects on the
benthic fauna and flora leading to lower fauna and flora densities under the cages or
even defaunated sediments (Delgado et al. 1997; Karakassis et al. 2002). Other environmental impacts include release of chemicals, medicines and pesticides, which
are used for treatment of the fish and the farm installations. Interactions with wild
populations, spreading of disease and release of parasites from farms are also of
environmental concern.
The environmental impacts of marine aquaculture within the European Union are
regulated and managed, at a European level, through a variety of European
Commission (EC) Directives and International Conventions. There are currently eight
EC directives (Table 2.1) directly involved and an additional 50 + Directives,
Decisions and Regulations, which have an indirect effect (Read et al. 2001). In addition, three International Conventions on marine pollution cover EU coastal waters
(Table 2.2) and there are a further 30 + international agreements that have an indirect
effect on the monitoring and regulation of marine aquaculture (Read et al. 2001).
Within the European Union, the regulation of the aquaculture sector comes under the
remit of the Common Fisheries Policy (CFP). The CFP states that Member States
shall adopt provisions to comply with the objectives of regular monitoring of activities and technical controls. At EU level, environmental protection measures have been
established at three levels: (1) general policy; (2) specific measures; and (3) regulations that control specific local conditions (Eleftheriou and Eleftheriou 2001).
The regulations controlling aquaculture vary between countries, but most countries use some form of Environmental Quality Objectives (EQOs) and Environmental
Quality Standards (EQSs) (Table 2.3). Only a few countries apply a carrying capacity at the moment, but this has been suggested for future regulation within the
Integrated Coastal Zone Management (ICZM) approach (see below). Most countries have specific demands for the location of the farms to avoid situating these
near habitats of special interest (recreation, wild life, fishing zones) and near industries and sewage outfalls. Requirements on stocking density, feed type and sediment and water quality standards are also included in most regulations. A few
countries regulate the production based on discharges, e.g., N and P release per kg
M. Holmer et al.
range of impacts from aesthetic to direct pollution problems (Fig. 2.1, Pillay 2004).
Fish production can generate considerable amounts of dissolved effluents, which
potentially affect water quality in the vicinity of the farms, and due to rapid dilution, also at larger scales (km-scale). Due to the rapid dilution it has been difficult
to document the effects of dissolved nutrients in farm vicinities, in particular in
areas with relatively high nutrient concentrations such as in the Baltic Sea
(Christensen et al. 2000). Other studies of fishery landings in the Mediterranean
suggest that nutrients are rapidly transferred up the trophic chain enhancing secondary production (Machias et al. 2005), indicating that monitoring of nutrient losses
should be done at different scales. Due to rapid settling of feed and faecal pellets in
the vicinity of the farms, benthic impacts are much more widely documented
(Holmer et al. 2005; Kalantzi and Karakassis, 2006). This input of organic rich
material enhances the microbial processes in the sediments, often leading to anoxic
conditions (Holmer and Kristensen 1992). This may have major effects on the
benthic fauna and flora leading to lower fauna and flora densities under the cages or
even defaunated sediments (Delgado et al. 1997; Karakassis et al. 2002). Other environmental impacts include release of chemicals, medicines and pesticides, which
are used for treatment of the fish and the farm installations. Interactions with wild
populations, spreading of disease and release of parasites from farms are also of
environmental concern.
The environmental impacts of marine aquaculture within the European Union are
regulated and managed, at a European level, through a variety of European
Commission (EC) Directives and International Conventions. There are currently eight
EC directives (Table 2.1) directly involved and an additional 50 + Directives,
Decisions and Regulations, which have an indirect effect (Read et al. 2001). In addition, three International Conventions on marine pollution cover EU coastal waters
(Table 2.2) and there are a further 30 + international agreements that have an indirect
effect on the monitoring and regulation of marine aquaculture (Read et al. 2001).
Within the European Union, the regulation of the aquaculture sector comes under the
remit of the Common Fisheries Policy (CFP). The CFP states that Member States
shall adopt provisions to comply with the objectives of regular monitoring of activities and technical controls. At EU level, environmental protection measures have been
established at three levels: (1) general policy; (2) specific measures; and (3) regulations that control specific local conditions (Eleftheriou and Eleftheriou 2001).
The regulations controlling aquaculture vary between countries, but most countries use some form of Environmental Quality Objectives (EQOs) and Environmental
Quality Standards (EQSs) (Table 2.3). Only a few countries apply a carrying capacity at the moment, but this has been suggested for future regulation within the
Integrated Coastal Zone Management (ICZM) approach (see below). Most countries have specific demands for the location of the farms to avoid situating these
near habitats of special interest (recreation, wild life, fishing zones) and near industries and sewage outfalls. Requirements on stocking density, feed type and sediment and water quality standards are also included in most regulations. A few
countries regulate the production based on discharges, e.g., N and P release per kg