Fernandes_et_al._2001

The scienti®c principles underlying the monitoring of the environmental impacts
of aquaculture
By T. F. Fernandes1
, A. Eleftheriou2
, H. Ackefors3
, M. Eleftheriou2
, A. Ervik4
, A. Sanchez-Mata5
, T. Scanlon6
,
P. White7
, S. Cochrane7
, T. H. Pearson7,8
and P. A. Read1
1
Napier University, School of Life Sciences, 10 Colinton Road, Edinburgh, EH10 5DT, Scotland; 2
Institute of Marine Biology
Crete, PO Box 2214, 710 03, Heraklion, Greece; 3
Department of Zoology, Stockholm University, S-10691 Stockholm, Sweden;
4
Institute of Marine Research, Bergen, Norway; 5
Dpto. Biologia Animal, Facultad de Biologia, University of Santiago, 15706
Santiago de Compostela, Spain; 6
Irish Sea Fisheries Board, PO Box 12, Crofton Road, Dun Laoghaire, Co. Dublin, Ireland;
7
Akvaplan-niva, Polar Environmental Centre, 9296 Tromsù, Norway; 8
SEAS Ltd, Dunsta€nage Marine Laboratory, PO Box 3,
Oban, Argyll, Scotland
Summary
This paper provides a critical review of the main issues
regarding the scienti®c principles underlying environmental
monitoring of marine aquaculture operations and makes
recommendations relevant to the implementation of best
practice for the management of aquaculture in Europe. Given
that a variety of cultured species and approaches are adopted
in Europe, it is not possible, or indeed desirable, to devise
prescriptive guidelines. Instead, this paper reviews how science
informs monitoring and provides a framework for the devel-
opment of a monitoring strategy of marine aquaculture
operations that is ¯exible enough to be applicable to a variety
of locations, species and situations.
Traditionally environmental monitoring has concentrated
on a few key physical and chemical variables and organisms.
The trend now, however, is towards whole-system environ-
mental assessment (e.g. CEC 20002 ; Osparcom 19983 ), including
considerations of the assimilative capacity of speci®c systems
and their ability to absorb and dilute perturbations. Against
this background this paper addresses the following speci®c
objectives:
· review of the rationale and scienti®c principles underlying
current environmental monitoring with speci®c reference to
marine aquaculture;
· evaluation of the links between monitoring and regulatory
criteria, speci®cally consideration of environmental quality
objectives and environmental quality standards, and the role
of environmental impact assessment;
· assessment of the role of codes of best conduct and practice,
and environmental management systems in the management
of aquaculture operations.
The paper concludes by proposing a set of recommendations
which will contribute towards the sustainable management of
aquaculture operations, through the implementation of a more
focused approach to environmental monitoring.
Aquaculture, environment and sustainability
The aquaculture industries have seen large expansion over
past decades, and subsequently, attention has been given to
the environmental e€ects of such activities. It is not possible
to generalize and distinguish between the actual and potential
impacts of aquaculture given that a multitude of approaches
is in place. However, in general, the potential impacts of
aquaculture are wide-ranging, from aesthetic aspects to direct
pollution problems (O'Sullivan 1992). Marine aquaculture
operations and the associated infrastructure can, for example,
impact on scenic rural areas. Fish production generates
considerable amounts of e‚uent (e.g. nutrients, waste feed
and faeces, together with associated by-products such as
medication and pesticides) that can have undesirable impacts
on the environment (Gowen and Bradbury 1987; Ackefors
and Enell 1994; Wu 1995; Axler et al. 1996; Kelly et al. 1996).
There may also be unwanted e€ects on wild populations, such
as genetic disturbance (Crozier 2000; Fleming et al. 2000), and
disease transfer by escapees or ingestion of contaminated
waste (Heggberget et al. 1993), and e€ects on the wider
ecosystem. Table 1 summarizes current environmental con-
cerns arising from marine aquaculture operations. Other
coastal activities can also have unacceptable impacts on
aquaculture operations (e.g. e‚uent discharges and physical
con¯icts with other users; Anderson 1995; Shereif and Mancy
1995; Phyne 1996).
The main aim of monitoring is to assess whether an activity
is having an unacceptable impact on the environment, the
threshold of acceptability normally being decided on societal
grounds. The ultimate aim for both producers and regulators
is that an area designated for aquaculture may be used
inde®nitely in the broadest of senses (sustainable use).
Achieving this requires environmentally compatible farm
practices (Wu 1995).
Direct outputs from aquaculture operations to the aquatic
environment may be summarized in three broad categories:
aquaculture production (seasonal discharges), farm activities
and medication (periodic discharges). The behaviour of any
type of waste released into the water column depends on the
hydrographic conditions, bottom topography and geography
of the area in question. Dissolved products include ammonia,
phosphorus, dissolved organic carbon (which includes dis-
solved organic nitrogen and dissolved organic phosphorus)
and lipids released from the diet, which may form a ®lm on the
water surface (Black 2001). The environmental impact of these
dissolved products depends on the rate at which those
nutrients are diluted before being assimilated by the pelagic
ecosystem. In restricted exchange environments, there is a
risk of high levels of nutrients accumulating in one area
J. Appl. Ichthyol. 17 (2001), 181±193
Ó 2001 Blackwell Wissenschafts-Verlag, Berlin
ISSN 0175±8659
Received: January 26, 2001
Accepted: March 26, 2001 1
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(hypernutri®cation) and potentially causing undesirable4 e€ects
(Midlen and Redding 1998).
In shallow waters, with weak currents, solid waste products
from aquaculture installations will settle to the bottom close to
the discharge point. In this case, continued production can give
rise to a rapid local accumulation of waste material on the sea
¯oor. On the other hand, e‚uent released into deeper waters,
or where the bottom is well-swept by strong currents, will be
dispersed over a larger area.
The vast majority of the chemicals used by the aquaculture
industry are for the treatment or prevention of disease, although
cleaning agents are also used (Costello et al. 2001; this issue).
The environmental concerns over the use of chemicals in the
aquatic environment relate to the following (Midlen and
Redding 1998): (i) the direct toxicity of the compounds;
(ii) the development of resistance to compounds by pathogenic
organisms; (iii) the prophylactic use of therapeutants; and
(iv) the length of time they remain active in the environment.
In addition to selecting sites with good water exchange,
management practices that minimize food waste and chemical
usage will also reduce the environmental impacts of aqua-
culture and optimize ®sh health and growth (Cho et al. 1994;
Ervik et al. 1994).
The scienti®c principles underlying environmental monitoring
Development of a rationale for monitoring
According to GESAMP (1986), sound environmental man-
agement deals with the allocation of natural resources and
methodologies in such a way that the environment can be used
in a sustainable manner in the context of a speci®c social,
economic and political framework. Therefore, the potential
use of the environment as a means of disposing of waste is
included in this process. Nevertheless, in order to achieve
sustainable management, such use must be with the knowledge
that any potential environmental e€ect is localized, reversible
and short-term. It is within this framework that scienti®c
knowledge is necessary so that decisions taken can be widely
accepted and implemented in an optimal manner.
GESAMP (1996) suggest a working de®nition of monitoring
as `the regular collection, generally under regulatory mandate,
of biological, chemical or physical data from predetermined
locations such that ecological changes attributable to aqua-
culture wastes can be quanti®ed and evaluated'. This de®nition
is useful and provides a framework for this review and
discussion.
Monitoring should be informed by suitable research so
that adequate methodologies are developed to address key
variables to monitor. It is important that good knowledge is
available so that, not only adequate methodologies are used
and appropriate variables are targeted, but also the results can
be interpreted against a background of spatial and temporal
natural variability. Considerations of sampling design, repli-
cation, and setting of controls are central to this discussion.
One of the main objectives of monitoring exercises is the
assessment of `environmental status' against a `control' or
`reference area', as an indication of environmental change. It is
essential therefore that the variables sampled are the correct
ones to provide an indication of such change. In addition, it is
important that the results can distinguish localized and short-
term changes from longer term environmental changes.
Therefore, it is essential that background environmental
variability is assessed, deviation from background conditions
is established, evaluation and signi®cance of that deviation is
conducted and acceptable change de®ned (Elliott and O'Reilly
1991). In this context, it is important to stress that deviation
from norm, acceptable change and potential for recovery,
should be assessed and established since pristine conditions
may not be maintained at all times and in all locations (see
`The role of EQOs and EQSs' below).
The ideal monitoring programme would therefore be the one
which, through selection of adequate variables and design and
frequency of sampling, would give a `signal', above natural
background `noise', and would provide an indication of
environmental status. The above focuses on the scienti®c
requirements for adequate monitoring; however, there are
practical constraints that need addressing. In simple terms,
they concern two main areas: time-span and ®nances. In
addressing these factors mathematical modelling can provide
essential information regarding potential spatial and temporal
impacts and therefore make a direct contribution to the design
of the monitoring exercise. For example, simulation exercises
regarding biomass culture, regime and locations, can be
undertaken and results can then inform the future manage-
ment system and monitoral procedures.
The role of environmental impact assessment
The EC Directive on environmental impact assessment (EIA)
(85/337/EC) as amended by Directive 97/11/EC seeks to ensure
that where a development or project is likely to have signi®cant
impacts on the environment, the potential e€ects are system-
atically addressed in a formal environmental statement.
Therefore, an environmental statement (ES) is required for
activities of certain dimension and scope, following criteria
laid down in the above Directives. The implementation of this
Potential direct impacts Potential consequences Management actions
Organic enrichment Impact on wildlife/habitats Locational guidelines
Nutrient enrichment Trigger of toxic blooms Biomass maximum
Chemicals release Demise of wild stocks Maximum feed limit
Spread of diseases Restricted use of chemicals
Management guidelines (including
codes of practice/conduct)
Escapees `Genetic dilution' Improved cage design
Demise of wild stocks Management guidelines
Interaction with other Visual impacts and con¯ict with, Locational guidelines
coastal activities e.g. tourism, recreation ®shing,
maritime transport
Derive regional/local coastal plans
and integrate with national coastal
management plan (not addressed
in this paper)
Table 1
Current environmental concerns
arising from marine aquaculture
operations
182 T. F. Fernandes et al.

process ensures that information and data regarding the
physical, chemical and biological environments are collated. In
addition, data and information on socio-economic issues are
also compiled, which provide a wider set of background
material against which decisions can be taken.
Information and data gathered at a pre-operational stage
can be used to provide information for recommendations on
best management and for comparison with data collected at
later stages in the process. Although a review of the EIA
process is outwith the scope5 of this paper, it is important to
stress that the compilation of an ES improves the overall
management process. Nevertheless, there seems to be much
variability between European countries regarding the imple-
mentation of the EIA Directives. For example, in the UK,
although there are no relevant planning controls at present,
EIA is an integral part of the process for considering
applications for marine ®sh farm leases. There are now
speci®c regulations in place in the UK which apply to
proposed developments in sensitive areas; those designed to
hold a biomass of 100 tonnes or more; or that cover an area
in excess of 0.1 hectares of the surface area of marine
waters, including structures or excavations. These regulations
do not apply to shell®sh developments. In Spain, the EIA
regulations apply also to shell®sh developments through the
Royal Decree 38/1989 (application of the Directive of the
European Council 79/923/CE) and through the Spanish Law
of Marine Farming (Law 23/1984) (SaÂ nchez-Mata and Mora
2000).
GESAMP (1994) refers to marine environmental assessment
as `the collection, analysis and interpretation of information
with the purpose of assessing the quality of marine areas'. This
includes a collection of reliable physical, chemical and biolo-
gical information against which the impact of anthropogenic
activities can be assessed. Crucial in this context is the
assurance that correct coverage of spatial and temporal
variability are adequately considered.
The role of EQOs and EQSs
In many countries, environmental quality objectives (EQOs) are
determined and established so that the environment can be
managed in such a way that these objectives would be achieved.
Environmental quality standards (EQSs) are then set for speci®c
variables in order that the objectives are attained. Therefore,
quality standards are now implicit within any process of
regulation, enforcement and quality control. In those countries
they are believed to be important to protect the consumer, the
environment and also the `product' (®sh or shell®sh).
Therefore, many countries [e.g. Scotland (Henderson and
Davies 2000); Norway (Anonymous 1993, 1999; Hydro Sea-
food Norway AS 1999); Sweden (Ackefors 2000)] now operate
the EQO/EQS system in their approach to managing the
environmental impacts of di€erent activities. The uses of the
aquatic environment are set, e.g. consumer protection (edible
aquatic species may be safely eaten), protection of aquatic life,
protection of water quality for industrial use, water sports,
nature conservation, Standards or criteria are then established
to protect these uses and applied by the competent authority in
regulation. Quality standards may be set nationally, for
example List I and List II and Red List substances (e.g. under
the Dangerous Substances Directive (76/464/EEC) and its
daughter directives, for example, the Cadmium Directive (83/
513/EEC)), or they may be locally derived from available data
(e.g. sediment quality) to provide operational guidelines (Read
et al. 2001).
Inherent within the EQO/EQS approach is the concept of a
mixing zone where EQSs may not be met. In relation to
speci®c operations, regulatory bodies often use an allowable
zone of e€ect (AZE) for both sediments and the water column
(SEPA 1998), or a local impact zone (also called `inner zone')
to which a special set of EQSs may apply (Ervik et al. 1997).
For salmon cages, the Scottish Environment Protection
Agency (SEPA) has de®ned the extent of the AZE and criteria
to be achieved within it and uses it operationally in reviewing
monitoring data and determining action (Henderson and
Davies 2000).
Devising a monitoring programme ± scienti®c considerations
Purpose. The objectives (purpose) of any monitoring exercise
are: (i) to provide information on the area where the operation
will take place (pre-operational); (ii) to provide information on
which management guidelines/recommendations can be based
(pre-operational); and (iii) to act as a `temporal and spatial
control' (operational and post-operational) upon which reme-
dial action might be based.
Variables which would address the questions being asked.
Variables that can be sampled are multiple and they depend
mostly on the farming operation and the receiving environ-
ment. Table 2 displays some of these variables. In addition, it
is important to ascertain whether the targeted area has any
special features (protected/listed habitat and/or species) that
could impose particular (more stringent) management consid-
erations on the operation, or is being used by any other
stakeholders (e.g. ®shing, recreation, waste discharge, indus-
trial operation).
Di€erent variables might be sampled at di€erent times
during the project lifecycle. It is proposed that the initial survey
could be more comprehensive so that a baseline could be better
de®ned, special features, if any, identi®ed, and management
recommendations provided. A post-operational monitoring
Table 2
Variables commonly used in moni-
toring assessment
Physical Chemical Biological
Bathymetry
Currents, waves, tides
pH, alkalinity
Redox
Species abundance and diversity:
plankton, benthos, nekton, birds
Wind Temperature (qualitative, i.e. species list, or
Precipitation Salinity quantitative, i.e. full abundance)
Substrate type Dissolved Oxygen (DO)2828 Biomass
Sediment movement Nutrients Productivity
Erosion/accretion Particulate/dissolved organic matter Population structure
Suspended solids Trophic interactions
Speci®c chemicals (depending on Habitat mapping
the operation) Rare and endangered species/habitats
Scienti®c principles underlying the monitoring of the environmental impacts 183

process could then focus on speci®c key variables. These could
act as surrogate (i.e. variables which can be sampled e€ortlessly
and will give an indication of overall environmental changes,
e.g. sediment redox potential) and could provide the informa-
tion necessary on the overall status of the environment and, if
necessary, trigger any management decisions.
It is also important to specify which sampling devices should
be used to sample speci®c variables. For example, regarding
substrate sampling, remote devices can be used (e.g. video,
photography) but in most sedimentary situations cores (col-
lected by divers or from boats) and grabs tend to be used
(Holme and Mcintyre 1984). It is important that sample volume
is agreed and standardized, including treatment, preservation
and analyses of samples, and that analytical quality control
procedures are established and followed (Rees et al. 1990).
Intensity (replication) and frequency of sampling (e.g. consid-
eration of season). In this context, intensity refers to replication.
The function of a `reference' or baseline situation is to provide
enough information against which the quality of the environ-
ment can be assessed (Glasby and Underwood 1996). Given
natural spatial variability and patchiness it is important that a
degree of reliability can be placed on the results obtained.
Simulated sampling programmes are recommended to establish
the required sampling intensity and frequency of relevant
variables. Power analysis can be used to de®ne how many
replicates should be taken in order to assess reliably any
potential deviations from the baseline (for details see Zar 1996;
Underwood 1997). The expected speci®c natural environmental
variability should be included in the calculation. This would be
di€erent for di€erent variables (e.g. see Rees and Pearson 1992;
for details regarding natural variability in macrobenthic sedi-
mentary systems). Replication, however, needs also to be
considered following practical considerations regarding labour
and time considerations. In addition, considerations of pseu-
doreplication need to be taken into account; that is, samples
used in statistical testing must consist of truly replicated data
(for details see Hurlbert 1984; Zar 1996; Karakassis et al. 1998).
Regarding the frequency of sampling, it is important to
consider whether there might be requirements to sample at
di€erent time periods/seasons and include such considerations
when designing the exercise. This could be necessary in
particular cases (e.g. areas of particular conservation interest)
where the status of speci®c organism developmental stages may
need to be assessed. In addition, the sampling exercise should be
repeated at roughly the same time/season so that patterns can
be compared across the years. It is, in fact, important to
consider the signi®cance of sampling at di€erent times of the
year, as whereas a sampling exercise during the cold season
would allow detecting the `net' accumulation of discharges, a
similar exercise during the warm season would most likely
indicate the extreme conditions that would prevail in the area.
Sampling design. Sampling design considerations include
number of samples, location and replication. The latter has
already been addressed. The speci®c sampling design adopted,
for example the number and speci®c location of stations,
cannot be speci®ed here as this would depend on the
geography, speci®c objectives and ®nances (more details,
however, are provided in `Comparison with the reference sites
and general design' below). Nevertheless, it is essential that
important habitats and species are covered adequately and so
sampling sites should be randomly allocated (Underwood
1997). The establishment of reference conditions should be
achieved by selecting two or more sites of similar environ-
mental conditions to the site being investigated. The rationale
behind this is the requirement to minimize potential problems
regarding `unusual' sites and allow for natural variability,
while considering practical constraints. A wide discussion on
the selection of reference stations is included in the compre-
hensive studies task team (CSTT 1997).
Another consideration regarding the distribution of samp-
ling sites concerns topography and hydrography. A uniform
depth and substratum type over the sampling area would allow
the assessment of conditions within each site that are due to
anthropogenic disturbance and not to di€erent environmental
conditions (Rees et al. 1990).
Speci®c considerations of sampling design may be addressed
in special cases. For example, in areas of conservation interest,
where a species/habitat might be of special concern, the
identi®cation of spatial structuring may be important and so a
nested sampling design could be considered (see Underwood
1997; for further details).
Methodologies to be employed, including data analyses. Di€er-
ent types of numerical techniques can be applied (e.g. Clarke
and Warwick 1994; Zar 1996; Underwood 1997). These must
be appropriate to the design used, address the objectives and
allow comparisons. Rees et al. (1990) and Clarke and Warwick
(1994) describe a series of numerical techniques that are widely
used in environmental monitoring. It is neither possible, nor
desirable, to be prescriptive regarding the use of numerical
techniques, although it is suggested that a combination of
simple statistical techniques should be used, as appropriate
(e.g. analysis of variance, regression). In addition, there are
speci®c numerical methods that are standard in environmental
data analyses. These include univariate summary indices (e.g.
species diversity indices, biotic indices) and multivariate
techniques (e.g. cluster analysis and ordination).
A series of numerical indices and methods which focus on
the macrobenthos have been suggested for monitoring and
management purposes in coastal waters (e.g. Satsmadjis 1985;
Majeed 1987; Wilson and Je€rey 1987; Word 1990; Codling
and Ashley 1992). Such indices include the infaunal trophic
index (Word 1990), the biological quality index and the
pollution load index (Je€rey et al. 1985), the pollution
coecient (Satsmadjis 1985), the `0±7 biotic indices', as
reported by Majeed (1987), the benthic quality index (Wilson
and Je€rey 1987), the benthic pollution index (Leppakoski
1975) and the benthic community index (Westerberg 1978).
These indices are either based on the perceived tolerance of
selected taxa to disturbance (principally organic pollution) or
more precisely based on some ecological properties that are
intrinsic to the considered taxa. The latter apply speci®cally to
the way organisms acquire their main energy sources and are
normally referred to as `biotic indices'. The index that has
been, arguably, used and tested in a wider context is the
infaunal trophic index (ITI). It was originally developed by
Word (1978) and its initial objective was to help identify
degraded environmental conditions resulting primarily from
organic pollution in the coastal waters of southern California.
The ITI falls in the category of a biotic index and the ®rst step
involves the allocation of species to one of four groups based
on the type of food consumed and where the food was
obtained (see Word 1990). As it has been demonstrated that
feeding categories can be roughly linked to levels of organic

matter in the sedimentary environment, the ITI can then be
used to indicate organic pollution.
Interpretation. As described by Usher (1991), statistical tests
allow a null hypothesis to be tested, but care needs to be taken
when deciding what the alternative hypothesis is. This point
relates to some of the considerations already made (replica-
tion, design and numerical methods). In addition, it is
important that results are put in context of a wider back-
ground (e.g. regional and national monitoring programmes) so
that any trends can be assessed against a `bigger picture'.
E€ects might be recorded within the vicinity of the operation;
however, it is important that these are put within the context of
their signi®cance in the wider environment (Rees et al. 1991).
Rees and Pearson (1992) suggest a methodology for the
derivation of EQSs that can be used to assess the departure
from reference conditions in sedimentary substrates.
It is important that the monitoring process is dynamic, and
is assessed and reviewed periodically so that further scienti®c
knowledge is added to the process and the design is appropri-
ate to changing situations and environments.
Current issues in aquaculture monitoring
Challenges for monitoring and legislation
Localized and far-®eld e€ects. The impact of aquaculture
operations is dependent on the methods used, site location,
production scale, management approach and the assimilative
capacity of the surrounding environment (Table 3; GESAMP
1986; Rosenthal et al. 1988; Ackefors et al. 1994). Usually
environmental monitoring programmes are designed to identify
and assess the local impact, rather than the potential larger-
scale, or far-®eld e€ects. However, dissolved contaminants and
nutrients, and to a certain degree, particulate material, arising
from these operations may be spread over larger areas in the
receiving water body and sediments. Indirectly, contaminants
may potentially be spread through wild populations of inver-
tebrates, ®sh and other vertebrates in the area. At present, far-
®eld e€ects are dicult to quantify, and generally have not been
routinely monitored. Nevertheless, it has been suggested that
aquaculture, in combination with other activities, can contrib-
ute towards enhanced concentration of nutrients in coastal
areas (Ackefors and Grip 1995). However, current knowledge
and evidence are insucient to provide7 clear con®rmation of
such a relationship (Pitta et al. 1999 and references therein).
Single unit and multi-units in enclosed areas. Many environ-
mental monitoring programmes assess the impacts of single
farm units in isolation from other aquaculture farms or other
sources of pollution that may be located in the same area. It is
therefore important to consider other users of the same waters
to assess the cumulative e€ect of all sources of pollution on the
environment (Ackefors and Enell 1990; Ackefors and Grip
1995). In this respect, the monitoring of multi-operations in a
single receiving water body should be co-ordinated and
adapted to the speci®c situation. In addition, modelling should
be use to assess the potential cumulative environmental e€ects
of multiple sources.
In areas where there are multiple potential contamination
sources within the same body of water, the possibility for
synergistic e€ects should be considered through modelling. In
this context it is important to consider how di€erent environ-
ments may be a€ected in di€erent ways by multiple operations
and therefore the monitoring programme will have to assess
the potential assimilative capacity of the system (Table 3) and
any outcomes should be incorporated when designing future
monitoring programmes. It is recommended that further e€ort
should be put into the development of methodologies that can
be used to assess the potential cumulative impacts of multiple
operations, and that the development of hydrodynamic and
ecological models, which would address the assimilative
capacity of speci®c coastal areas, should be encouraged.
Interest groups and project/production cycles
The monitoring programme should target three main interest
groups, the scientists, the regulators and the producers, each of
which is responsible for contributing and extracting di€erent
types of information. Nevertheless, it is important that
throughout this process other stakeholders are also considered,
namely non-governmental organizations, consumers and
interested members of the public. The overall management of
aquaculture operations should aim towards the development
of best environmental practice (BEP), which can be de®ned as
the implementation of procedures that would ensure the
sustainable management of aquaculture.
From the regulator's point of view, the aim of a monitoring
programme is to develop an easily enforceable BEP that
complies with the requirements of the EU, national regulations
and set EQOs. The regulator is responsible for de®ning
potential con¯ict of use of proposed or existing aquaculture
operations and may demand a higher monitoring intensity
where aquaculture activities compete with other uses of an
area, such as tourism, recreation, nature conservation, ®shing,
housing developments or industrial operations (Ackefors and
Grip 1995; Fernandes and Read 2001). The data obtained
must also be cost-e€ective in assessing impact. The required
investigative variables should be restricted to those that are
proven scienti®cally to be potential measures of environmental
Table 3
Concepts widely used in aquaculture
management (Gesamp 1986; Rosenthal
et al. 1988)
Term De®nition
Carrying capacity of a de®ned area refers to the potential maximum production of a species
or population that can be maintained within that area in relation to the
available food and environmental resources.
Holding capacity is the potential maximum production which is limited by a non-trophic
resource.
Assimilative capacity is the ability of an area to maintain a `healthy' environment and
`accommodate' wastes.
Production capacity is the maximum tonnage level that can be attained without producing a
negative impact on the environment and on the farmed stock.
Environmental capacity refers to the ability of the environment to accommodate a particular
activity or rate of activity without an unacceptable impact.

hazards, or those that can be used as indicators of environ-
mental impacts. The regulators normally issue a consent prior
to any farm operation (e.g. Ackefors 2000; Henderson and
Davies 2000; Maroni 2000). Conditions issued as part of the
consent process should be unambiguous, enforceable, clear
and necessary. Setting consent limits normally takes account of
a zone of e€ects close to the centre of the operation, where
separate conditions may apply (e.g. AZE, see above). Typically
a consent includes details of the treatment calculations and
quantities of therapeutants required, maximum biomass, feed
quota, site location and species to be farmed, and a site-speci®c
monitoring programme with protocols and detailed guidance.
From the scientist's point of view, the aim of a monitoring
programme is to achieve a scienti®cally sound BEP. This
requires that the methods used and data acquired are based on
sound scienti®c principles and standard methodology. The
scientists involved are responsible for keeping the monitoring
programme updated in terms of relevant research ®ndings.
From the producer's point of view, the aim of a monitoring
programme is to achieve an a€ordable, applicable, useful and
easily understandable BEP. The producer is often responsible
for designing and following an optimal management regime
aimed at sustainable use of the concession area throughout the
production life of the operation. The producer-orientated part
of the monitoring programme should include a simple educa-
tional section to ensure that the producer has up-to-date
information and understands the wider implications (environ-
mental and legislative) of the operation.
Production cycle/phases. The monitoring programme should
be adaptable in order to apply to di€erent phases in the
production cycle. Therefore, the intensity of monitoring
prescribed by the authorities should be adjusted according
to: (i) whether the investigated area is a potential farm location
or has already been in operation; (ii) the site history, namely
the length of time it has been in operation, production volume,
species, feeding regimes, food conversion ratios; (iii) whether
fallowed sites are intended for re-use or are permanently
decommissioned.
Thus, several `levels' of monitoring survey should be
designed to cater for the di€erent requirements. In this way,
the costs of the programme, as a whole, are kept to a minimum
without sacri®cing the required information. The survey costs
for each individual operation would be further reduced by
co-ordinating the sampling within geographic areas such that
several operations can be visited at the same time. This
requires strict procedures for hygiene and disinfection of
equipment, as speci®ed by existing regulations.
General requirements of a monitoring survey
De®ning impact. In an EU-wide or international monitoring
programme, a de®nition of environmental impact and accept-
able levels thereof should be mutually agreed upon. These
could be presented as a series of regional guidelines so that
natural variations in background levels of organic material
and contaminants can be taken into account. Considerations
of EQOs and corresponding EQSs, as already discussed in
`The role of EQOs and EQSs' should be included. Overall,
environmental changes recognized as unacceptable `impacts'
must:
· be of `signi®cance' for the environment or the production of
the species cultured;
· be clearly distinguishable from background conditions;
· be quanti®able using methodology that is available in most
European countries.
It is accepted that stricter conditions might be imposed in
areas where the natural environment, or uses of, justify such
action. Further, the de®nition of unacceptable impact must be
such that it can be monitored in a cost-e€ective manner. In
situations (e.g. in areas of special conservation interest) where
there may be reasonable grounds to suspect that wider-®eld
`serious' impacts may occur, the `precautionary principle', as
enshrined in European legislation, may be applied.
The fundamental aims. Following from `The scienti®c princi-
ples underlying environmental monitoring' discussed above,
the results obtained from an environmental monitoring pro-
gramme should address the following questions: (i) what are
the environmental impacts in the near-®eld; (ii) how large an
area is a€ected. However, these are general questions that need
to be addressed speci®cally. In practical terms, three levels
should be considered, namely (i) does the situation in the
immediate vicinity of, or directly below, the operation comply
with the criteria set for the near zone of impact, AZE; (ii) do
the environmental variables sampled outside the AZE comply
with the EQSs set for the medium ®eld and, if not, how large is
the deviation and; (iii) how much, if any, do the environmental
variables assessed in the middle/far ®eld di€er from the ones
sampled at the reference sites. Deterioration in conditions
should be speci®ed and interpreted, giving guidelines for
remedial action.
Scale of impact. Recognizable criteria should be developed
which allow the area to be classi®ed according to a scale of
`environmental impact'. This would also allow the conditions
at several locations to be compared with respect to relative
environmental conditions (Ervik et al. 1997). There should be
a de®ned `cut-o€' point, beyond which it is considered
essential to take remedial action or move the farm. It is
suggested that trend monitoring would provide early warning
of potentially changing environmental conditions. The cri-
teria used to assess levels of pollution should, however, be
¯exible enough to allow for the large naturally occurring
variability in local environmental conditions that may occur
even within a relatively small area. A worst-case scenario,
that is, a situation where the greatest impact would occur,
would be found at peak biomass in the summer months, all
other conditions being the same. Monitoring at or around
this time would allow the assessment of the prevailing local
management strategy and the identi®cation of any necessary
remedial action.
Area of impact. The survey should record the situation in the
immediate vicinity of, or directly below, the operation (SEPA
1998), as well as at areas some distance from the operations
(Ervik et al. 1997).
Much work has been done regarding the number of
replicates necessary when a speci®c predetermined assessment
(e.g. di€erence between two means of a sampled variable at
two spatial locations; for more details see Zar 1996) is
required. A decision on the smallest statistical population
di€erence between the two sites is required (Zar 1996) and
this can be obtained or estimated from previous scienti®c
work (e.g. Rees and Pearson 1992). Nevertheless, a di€erent
approach has generally been adopted in practical environmen-

tal monitoring work. With regard to benthic subtidal macro-
fauna, it is normally accepted that three to ®ve replicate
samples will provide the necessary information; however, if
®sh are sampled, visual techniques are employed or water
column samples (including physico-chemical parameters) are
required, the recommended replication could be over 10
(Samoilys and Carlos 20008 ). Rees et al. (1991) suggest that
in most ®ne silt habitats three replicate standard benthic grabs
(Van Veen or Day, area 0.1 m2
) are expected to collect 60% of
the species present in an area, and ®ve samples would usually
yield over 70%. The same authors suggest that the latter
should be preferred in quantitative surveys at stations where
repetitive sampling is likely to take place. With regard to
smaller sampling devices, such as corers taken by divers, or
smaller grabs (area 0.025 m2
) then it is possible that a larger
number of replicates would be required. It is not possible
though, to be fully prescriptive as it would depend on the local
conditions and on the local natural variability.
Comparison with the reference sites and general design. For
each location, at least two reference sites should be chosen to
give information on `normal' conditions at the area, as
described above in `Sampling design'. It is essential that these
sites are free from other known impacts. It is important to
consider how far from the centre of the operation the reference
sites should be located. Geographical considerations should be
included in this debate but it is important to note that
reference sites should be located at a certain distance upstream
from the operation (opposite direction to the prevailing
current), for example, 500 m or 1 km upstream (SEPA 1998;
Karakassis et al. 2000). It is important to note, however, that
coastal currents tend to be polarized (i.e. the two prevailing
currents tend to be at 180° to each other) along isobaths due to
`topographic steering'. Therefore, it is recommended that in no
situation should reference stations be established in a close
location (e.g. less than 500 km) to the aquaculture operation,
even if they are believed to be located `upstream'. The
reference sites should have a similar depth and substrate type
to the sites surrounding the aquaculture operation. Considera-
tions regarding AZE, as already described in `The role of
EQOs and EQSs', would need to be accepted.
A standard design used in benthic monitoring adopts a
transect with sites established at a certain distance downstream
from the operation centre. Other possible designs could
include orthogonal transects or a grid survey. There might
be di€erent reasons for adopting one speci®c design type, at
di€erent times in the production lifecycle, or in di€erent
situations, although it is important that the results should be
comparable. Notwithstanding, it is important that samples are
independent and that location, within a predetermined area, is
randomized so that statistical requirements are ful®lled. In this
context, sites located on a transect within the operation
footprint can be considered strictly non-independent if located
at a close range. If that is the design adopted it is important to
note that standard statistical tests, which require sample
independence, cannot be used to analyse the data. Other
widely available tests, such as certain univariate and multi-
variate analyses, can still be used.
Inter-year comparisons. Where an aquaculture farm is to be
monitored at regular intervals, it is essential that the informa-
tion obtained from each survey is directly comparable. Thus,
the same general techniques and assessment criteria should be
used, the sampling points should be constant, if possible,
between surveys and the time of the year (season) should be
roughly the same.
Levels of acceptability. Although it is not possible to avoid the
environmental impacts of aquaculture altogether, it is possible
to keep within certain limits. Therefore, as described in `The
role of EQOs and EQSs' above, a set of standards should be
developed which de®ne acceptable levels of impact.
De®ning such standards is not an easy task given the
di€erent conditions of site location and procedures. The
variables sampled, however, should be roughly standard. In
certain cases, it may be necessary to de®ne separate but
compatible standards for di€erent conditions, for example,
di€erent substrate types. In any case, the results from a
monitoring survey should be able to pinpoint where a
particular aquaculture operation lies relative to these de®ned
standards, in terms of their environmental impact. A scale or
ranking system should be devised to simplify the assessment
procedure and further monitoring should be devised with these
in mind (Hansen et al. 2001). Trend monitoring should help to
identify any potential problems.
Scienti®c rationale behind the methods
Hydrographic/water quality analyses and other assessments.
The dispersal of aquaculture discharges is dependent on the
hydrographic conditions and water exchange mechanisms in
the area. Environmental impact on bottom substrate and the
water column are minimized in areas with strong current ¯ow.
However, the degree of exposure must not exceed the physical
tolerance of the production installations or the culture
organisms. It is therefore important to measure a range of
hydrographic variables, particularly during the planning or
pre-licence phases. The most important information required
is as follows: current speed; current direction; neap and spring
variations; current residuals; bathymetry; winds and wave
action; temperature; salinity; water strati®cation; other
regional factors (such as ice action and super-cooled water in
cold-water areas).
As hydrographic conditions are seasonally variable,
measurements should be carried out at certain time intervals,
to take into account di€erent sea temperatures and seasonal
strati®cation/upwelling of bottom water masses. Peaks
in production activities should also be taken into consid-
eration.
Furthermore, if possible, hydrographic measurements
should be carried out at several sites within a given area to
assess local variations in hydrography that could a€ect the
aquaculture activities. For example, small variations in topo-
graphical features could cause local anomalies in current ¯ow.
Particular attention should be paid in sill-fjord, sill-loch areas,
or where there are small coves within a bay or gulf. In
addition, it is essential that accurate position ®xing is used and
that relocation of stations for time-series analysis or for
speci®c spatial monitoring, is considered.
Sensory measurements (e.g. presence of gas bubbles, sediment
colour, smell, consistency and softness) are also important in
providing a quick assessment of local environmental conditions.
In Norway, these are employed to assess environmental status in
the `local impact zone', as part of the Modelling-ongrowing ®sh
farms-monitoring (9 MOM) system, and a score system is used to
quantify the impact (Maroni 2000). In addition, redox

measurements, as mentioned below, provide a semi-quantitative
measure to assist with the sensory descriptors.
Chemical analyses. Chemical analyses of bottom sediments
around aquaculture sites quantify the levels of contaminants
or the chemical properties. These can be compared with
natural conditions in the area as well as prede®ned levels of
acceptability or consent.
Some measurements can be carried out in situ using probes
for which the results are immediately available. These include
the following variables, all of which give information on the
sediment loading: pH, redox (Eh), oxygen. Laboratory analy-
ses most often focus on the following: organic content,
hydrogen sulphide, sediment granulometry (indicative of
organic deposition, bottom current speeds and also used for
normalization of levels of contaminants) and heavy metals. In
addition, speci®c pesticides, medicinal agents, and antifoulants
may be analysed according to individual requirements.
Benthic faunal analyses. Changes in the organic loading of an
area results in marked changes in the fauna present on the sea
¯oor. Extensive work has been carried out in sedimentary areas,
for which a model framework has been developed in relation to
an organic enrichment gradient (Pearson and Rosenberg 1978).
The `normal' situation in undisturbed areas is a high species
diversity with few dominant species and relatively few individ-
uals representing each species. In general, organic loading of the
sediment leads to a reduction in species diversity and an
increase in the abundance of opportunistic species. However, if
the level of pollution becomes very severe, even opportunistic
species will disappear, such that there are no macro-organisms
present in extreme conditions. In such cases, if sedimentation is
not very heavy, a white bacterial layer may form on the
sediment surface. This principle of macrofaunal responses to
pollution gradients in marine communities is explained in detail
in Pearson and Rosenberg (1978). In this way, macrofaunal
organisms are a very sensitive indicator of sedimentary condi-
tions, allowing the detection of environmental impacts in
situations in which other methods might not record them.
Speci®c methodology concerning benthic faunal analysis
(Holme and Mcintyre 1984) would include, for example,
speci®cation of sieve mesh size (e.g. in northern latitude
coastal areas, 1 mm should be used, whereas in similar
situations in the Mediterranean, 0.5 mm should be used),
sample preservation and level of taxonomic identi®cation
[for standard monitoring practices in `low sensitivity' situa-
tions, a speci®c taxonomic resolution could be agreed, e.g.
family level; (Kingston and Riddle 1989; Karakassis
and Hatziyanni 2000). Rigorous analytical quality control
procedures must be developed for all areas of practical work
and implemented.
Regulation and enforcement of monitoring programmes
Within the EU and country regulations, there are a variety
of implementation strategies for environmental monitoring
ranging from voluntary self assessment undertaken by the
farm to enforced monitoring undertaken by approved inde-
pendent specialists or regulators.
Voluntary self-monitoring undertaken by the farm. In the
absence of regulator-imposed environmental monitoring
schemes, some farms are establishing environmental policy
statements and implementing voluntary environmental mon-
itoring programmes. It is recommended that the company
initially establishes an environmental policy and then under-
takes regular monitoring in such a way that good quality
monitoring practice is implemented and reliable data obtained.
The monitoring survey may take the form of remote sampling
(e.g. video, ROV, REMOTS), diver inspections and/or a semi-
quantitative sediment assessment (basic biological, physical
and chemical conditions) depending on site location, scale of
operation and site sensitivity. In Norway self-assessment
includes monitoring of ®sh well-being and the overall produc-
tivity of the operation.
An environmental policy establishes an overall sense of
direction and sets the principles of action for an aquaculture
company (Westwood and Taylor 2001). It sets the over-
arching goal as to the level of overall environmental
responsibility and performance required of the company,
against which all subsequent actions will be judged. An
environmental policy should: (i) be appropriate to the local
conditions, scale of operation and environmental impact; (ii)
be committed to maintain BEP for critical environmental
issues and to comply with other environmental relevant
criteria; (iii) recognize the environment as important both to
the sustainability and successful production from the farm;
(iv) integrate environmental decision-making in all aspects of
business planning and operations; (v) avoid signi®cant
environmental impact; (vi) be committed to continual
improvement in performance; (vii) aim for waste minimiza-
tion/cleaner production; (viii) recognize the interests of the
community and other stakeholders or coastal users. The
company needs to ensure that the methodology and data
analysis of the monitoring survey are correct and that some
of their own farm sta€ are trained to undertake the surveys.
The development of the international standards, such as the
ISO 14000 series on environmental management systems and
the European Union's Eco-Management Audit Scheme, has
been crucial in promoting the use of some environmental
management tools.
The incentives for both voluntary self-monitoring and BEP
ultimately are ®nancial. The concept of eco-labelling, which
would allow produce from environmentally approved farms to
have a higher market value, has been discussed but it is dicult
to set criteria for implementation (Monfort 1998). In most
cases, the intensity of enforced monitoring depends on the
current environmental conditions at the site. Therefore, as
voluntary self-monitoring allows the site management to
minimize impacts, this in turn would minimize the cost of
enforced monitoring. It is important that a culture of
monitoring within the industry is implemented and that any
obstacles/barriers are dispelled.
Voluntary monitoring undertaken by independent specialists. At
some farms voluntary self assessment is undertaken by
independent specialists and follows procedures highlighted
previously. The bene®ts to a company of high-quality volun-
tary monitoring include: (i) a pro-active measure for monit-
oring before enforced monitoring regulations are introduced;
(ii) `early warning' of deteriorating conditions and professional
advice on the remedial actions to be taken; (iii) ®nancial
bene®ts as above (where applicable); (iv) fostering a climate of
co-operation between the licensee and regulator; (v) enhanced
credibility with the local community and general environmen-
tal agencies.

Regulator-enforced self-monitoring with spot checks (auditing).
The regulator may enforce self-monitoring, carried out by
quali®ed personnel, with spot-checks, auditing or other means
of quality control of the results. It is highly recommended that
site sta€ attend a relevant training course on the monitoring
techniques and interpretation of results. Quality assurance and
analytical quality control practices need to be followed, as
highlighted above. In general, the results are sent to the
regulator, for evaluation of the necessary remedial action, if
appropriate. Audit programmes by regulators are essential and
also require adequate resources. The scope of enforced self-
monitoring is usually dependent on production history, future
production plans, site characteristics and the results of any
previous monitoring surveys. In some countries a degree of
¯exibility in monitoring programmes is adopted (e.g. SEPA
1998) and this can reduce costs to the industry; this is
especially important in small-scale operations. The intensity of
monitoring required is adjusted to the actual environmental
impact of the operations on the site and this encourages good
practice (Hansen et al. 2001).
Regulator enforced monitoring by independent specialists. If
appropriate, the regulator may enforce monitoring of aqua-
culture farms, carried out by independent specialists. This may
be carried out at predetermined intervals (e.g. 1±3 years
dependent on topology/production), or if results of a smal-
ler-scale monitoring survey show unacceptable conditions (e.g.
environmental impact exceeding the de®ned threshold of
acceptable e€ects). An independent survey may also be
enforced in cases where an aquaculture company fails to be
proactive in undertaking regular monitoring surveys, or in case
of any additional problems.
Codes of conduct and codes of practice
Codes of conduct and practice are important in establishing a
culture of good practice among operators, therefore facilita-
ting the overall management of aquaculture. Considerations
regarding monitoring can also be included within such codes.
Codes of conduct
The Guideline for Aquaculture Development (Code of Con-
duct) for aquaculture issued by FAO (1997), Svennevig et al.
(1999) and Anonymous (2000), are intended to provide
direction for national governments to promote sound aqua-
culture industries. The code of conduct proposed by the
Federation of European Aquaculture Producers is a frame-
work directed towards the industry itself (Hough 2001). By
producing this document, the industry provides itself with
guidelines for self-regulation. The ultimate goal is a framework
of BEP (sometimes referred to as best available practice or
BAP) or `code of good practice' in the day-to-day work of
aquaculture production. Hough (2001) states that the pro-
posed code of conduct is a voluntary and non-binding
document, drawn up in response to self-regulated sectoral
development.
A code of conduct is a document where general guidelines
are established and where a peer group condones a series of
actions that are held to be in the interest of society. Such codes
should reinforce the implementation of principles and stand-
ards that are held to be realistic and would maintain the
sustainability of the industry. Generally speaking, a code of
conduct should be able to cross frontiers and be free of local
and national considerations.
All codes should involve a process of consultation, negoti-
ation and agreement within a group of stakeholders that are
either directly involved or a€ected by the subjects. The
diversity of stakeholders is large, involving: (i) government
authorities, policy-makers, planners and regulators; (ii) pro-
ducers, farm operators; (iii) manufacturers and suppliers to
aquaculture; (iv) processors and traders of aquaculture prod-
ucts; (v) consumers; (vi) banks and investors; (vii) special
interest groups and non-governmental organizations; (viii)
researchers, social and natural scientists; (ix) international
organizations (regional, global) and; (x) media.
Codes of conduct are general rules and principles leading to
a responsible and sustained development of the industry. In
some cases these codes include practical guidelines for the
cultivation of aquatic organisms. In other cases they do not,
and instead they are supplemented with codes of good and best
practice.
Codes of good or best practice
Codes of practice take into consideration best available
methods, techniques, strains, optimal feeding regimes, envi-
ronmental sustainability, welfare of the animals and other
issues related to aquaculture. The codes of practice should
be a practical guide to help operators avoid causing
pollution and give recommendations on practices that
optimize the environmental management of the operations.
In addition, economic considerations regarding the future
growth and development of the sector are also included.
These codes of good or best practice (CBP) are practical and
applied guidelines that are more speci®c in nature than
general codes of conduct and are recommended practices at
farm level to ensure a responsible development of the
industry (Holmes 2001). Di€erent CBPs should be developed
depending on species, culture system and geographical
location.
The development of CBPs could be achieved through the
education of farmers, based on the latest scienti®c ®ndings.
The rapid technical development implies the need for the
continuous sharing of data and of practical and theoretical
information between the various stakeholders.
Recommendations
All production processes, including aquaculture, generate
outputs that may have environmental impacts. The degree of
signi®cance of this impact not only depends on the type and
intensity of production, but also on the surrounding environ-
ment; that is, users and uses, including nature conservation,
®shing, recreation, tourism, navigation. It is thus recognized
that the assessment of environmental impacts depends on
speci®c conditions, situations and environments. Therefore, in
order to help with the management of aquaculture operations,
EQOs and corresponding EQSs, have been developed, some of
which are based on EU directives. In the context of
aquaculture, standards exist to ensure the safeguard of the
aquatic and coastal environment and to ensure the sustain-
ability of ®sh and shell®sh production, avoiding health hazards
at the consumer level.
Against this background, it is widely accepted that
aquaculture requires a framework of regulations to ensure

sustainability and minimize potential environmental impacts.
Good management is essential so that any aquaculture
operations ®t, in a sustained manner, within the coastal
environment and with all other coastal activities, within a
framework of integrated coastal zone management (Fernandes
and Read 2001). This means that planning must be based on
good knowledge of the environment, including water bodies,
benthic conditions and the wider aquatic ecosystem, as well as
the surrounding land areas. Modelling should be used to assess
the potential impact of new operations or to assess potential
cumulative impacts of several users.
As part of good environmental management, aquaculture
operations must be monitored with regard to potential changes
in general pelagic and benthic systems. Monitoring practices
must be adapted to the character of the ®sh and shell®sh farming
operations. This must include the following considerations:
· aquaculture methodology (extensive, semi-intensive, inten-
sive or integrated);
· aquaculture technology (¯ow-through, open-cage or closed
systems, land-based or sea-based);
· the nature of the environment (coastal zone, semi-enclosed
areas such as the Mediterranean and the Baltic, shallow sea
areas such as the North Sea, Norwegian fjord systems,
o€shore conditions deep-sea);
· uses and users of the environment (e.g. nature conservation,
®sheries, tourism, recreation, navigation).
Widely used traditional monitoring practices measure speci®c
variables, such as temperature, salinity, organic matter and
nutrient levels, as well as direct impact on the benthic system. In
addition, environmental modelling is now increasingly used as
part of standard aquaculture management practice. If used
appropriately, it can assist with the prediction of environmental
impact of proposed aquaculture operations, monitor ongoing
production and with management procedures. Monitoring
activities, making use of various models, can be applied at the
pre-operational, operational or post-operational stages, and
must consider the various interests of the public, regulators,
producers and scientists (GESAMP 1996; Ervik et al. 1997).
Regulators, are interested in the overall impact of aqua-
culture on the environment. In this context regulations must
conform with international and national agreements relating
to the control of environmental impacts, through conformity
with EQSs.
The application for a permit/licence for aquaculture oper-
ations may require an EIA. Based on the outcome of the EIA,
a producer may obtain a licence to produce a certain amount
of a particular species, under speci®c conditions and employ-
ing certain methodologies and technologies. Producers are
aware that good water quality is a prerequisite for a successful
production. This means that farmers must practise good
husbandry with regard to feeding regime, feed quality, hygiene
and ®sh health. They should also practise rational farming
procedures that are cost-e€ective. It is essential to balance the
costs of, self-monitoring activities, feed quality and food
conversion ratios among other factors, with the income gained
from production. In this context, codes of conduct/practice are
increasingly being developed and implemented.
Scientists play an important role in environmental assess-
ment by devising EQOs and EQSs that require the application
of suitable methods for monitoring the environment. Models
or other methods are used to de®ne variables of interest, collect
data and report to producers and regulators about the
environmental quality and possible impacts of the aquaculture
operations.
Finally, the following considerations are recognized and a
number of recommendations are then proposed:
· aquaculture is an important activity in Europe for socio-
economic considerations and therefore the management
process, including monitoring, should be transparent, sim-
ple, ecient, and cost-e€ective;
· aquaculture is an established marine activity which increas-
ingly has interactions with other users: ®sheries, shipping,
coastal industries, nature conservation, tourism and recre-
ation;
· aquaculture is a complex activity which encompasses a range
of di€erent species, locations, methodologies and technol-
ogies;
· the environment is varied and diverse technical, cultural and
managerial approaches are taken in the planning and
regulatory processes, although under the same EU legislative
framework;
· aquaculture, in common with other producing industries,
has environmental impacts;
· scienti®cally informed monitoring forms the basis of sound
management and is essential to assure public con®dence;
· monitoring needs to address the needs of the operator, the
regulator and general public.12
Recommendation 1: sustainable management
The aim for both ®n and shell®sh producers and regulators
should be that an area designated for aquaculture may be used
inde®nitely. Codes of conduct, codes of practice and manage-
ment regimes should include ecient monitoring of discharges
and environmental e€ects and, if necessary, regular fallowing
could be considered in order to achieve this aim.
The key to environmental sustainability at a farm site is its
hydrographic character and the degree of impact is a result of a
balance between the assimilative and dispersive capacity of the
location and the biomass held on site. Farm sites with good
water exchange should be selected, if possible, in order to
reduce farm-related impacts. Management practices should
also minimize ®sh food waste in order to reduce environmental
impact of aquaculture and optimize the health of the species
cultured, thus enhancing the growth rates of stock. As
possible, the industry should adopt voluntary codes of
conduct, implemented at local level by speci®c codes of
practice and environmental management systems.
Recommendation 2: the use of models
Existing predictive impact models should be adapted or further
developed for all geographical regions, and once validated,
they should be used to assist the licensing, management and
monitoring procedures.
Recommendation 3: the requirement for an EIA
An EIA is required for activities of a certain dimension and
scope, following criteria laid down in EU Directive 97/11/EC,
amending Directive 85/337/EEC, onthe assessment of the e€ects
of certain public and private projects on the environment.
As there seems to be much variability amongst European
countries regarding EIA requirements for aquaculture opera-
tions, it is important to stress that the compilation of an EIA
improves the overall management process. In those instances,
where the implementation of the full EIA is not considered to be

practicable, it is recommended that some environmental studies
of a more limited nature should nevertheless be carried out.
Any environmental information and data compiled would
provide the background against which any future data and
information can be compared. In addition, information and
data gathered at a pre-operational stage can be used to provide
information directed towards recommendations on best man-
agement practices for the speci®c operation being addressed.
Recommendation 4: the EQO/EQS approach
Environmental quality objectives should be de®ned for coastal
waters and standards should then be set to address those
objectives. They will require a degree of ¯exibility to take
account of geographic di€erences. Examples could include:
safeguarding water quality; conserving aquatic ecosystems;
protecting consumers; consideration for other end users.
Quality standards may be set internationally (European
Directives), for example, List I and List II and Red List
substances (Dangerous Substances Directives), or they may be
locally derived from available data (e.g. sediment quality) to
provide operational guidelines. Inherent within the EQO/EQS
approach is the concept of a mixing zone (or AZE) where it is
accepted that standards may not apply or be less stringent.
This approach requires a de®nition of the extent of this zone
and the criteria to be achieved within it.
Recommendation 5: the development of appropriate
monitoring programmes
Monitoring approaches should be informed by the following:
species cultured (e.g. ®n®sh or shell®sh), biomass, methodo-
logy, technology, location (e.g. open sea, coastal, enclosed bay,
semi-enclosed sea, fjord, estuarine, land-based), type of feed
and chemicals used.
Speci®c sampling variables to be measured should be
determined by the set EQOs and EQSs, the type of operation
and the nature of the environment. The extent and frequency
of sampling should be determined by the scale of any impacts.
The results of monitoring surveys should provide the basis for
remedial action, if required.
Recommendation 6: the importance of wide-range surveys
A non-site-speci®c regional survey should be conducted peri-
odically to assess the wider impacts of aquaculture operations.
This should be the responsibility of the regulatory authorities
and could be integrated into national monitoring programmes.
Acknowledgements
This paper was funded as part of a `Concerted Action' project
under the European Union FAIR (aquaculture) research
programme as part of a project entitled `Monitoring and
Regulation of Marine Aquaculture in Europe' (contract
number FAIR PL98±4300). The authors would like to
acknowledge the constructive comments and suggestions
provided by Dr Yannis Karakassis, Mrs Anne Henderson,
Dr Terry McMahon and Dr Ian Davies.
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Authors' address:27 T. F. Fernandes (for correspondence), P. A. Read,
Napier University, School of Life Sciences, 10
Colinton Road, Edinburgh, EH10 5DT, Scotland;
A. Eleftheriou, M. Eleftheriou, Institute of Marine
Biology Crete, PO Box 2214, 710 03, Heraklion,
Greece; H. Ackefors, Department of Zoology,
Stockholm University, S-10691 Stockholm,
Sweden; A. Ervik, Institute of Marine Research,
Bergen, Norway; A. Sanchez-Mata, Dpto. Biologia
Animal, Facultad de Biologia, University of San-
tiago, 15706 Santiago de Compostela, Spain;
T. Scanlon, Irish Sea Fisheries Board, PO Box 12,
Crofton Road, Dun Laoghaire, Co. Dublin,
Ireland; P. White, S. Cochrane, T. H. Pearson,
Akvaplan-niva, Polar Environmental Centre,
9296 Tromsù, Norway; T. H. Pearson,
SEAS Ltd, Dunsta€nage Marine Laboratory,
PO Box 3, Oban, Argyll, Scotland

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