ECASA WP 2
Friday, 17 December 2004
Annotated sheet for indicators1
related to the impact of aquaculture on the environmenti
1- Name of indicator, authors
Univariate descriptions of macrofauna community (with some indices also applicable to
meiofauna)
S (number of species), A (Abundance), Biomass (B)
Also B/A, A/S, Shannon-Wiener H’ (diversity), Pielou’s (Evenness), Simpson, top 5 most
abundant species
Indicators species and families, ratio of biomass retained on 0.5 mm sieve to 1.0 mm sieve
(Karakassis and Lampadariou, unpublished)
Various authors for other indices
From Sams
2- Computation: Formulae, or model output.
Whenever possible, please use a range of 0-100. Ranking the results in few classes (five?) is
another option for qualitative indicators.
S, A and B, S/A, B/A are calculated from taxonomic identification species lists. H’, Evenness
and Simpson can then be subsequently derived. Formulae for these are given in standard
benthic ecology text books (e.g. Levinton, 1982), or are calculated by statistical packages, eg.
PRIMER.
Certain indicator species and families have been shown to indicate impact by their
presence/absence (recent example in the Mediterranean - Karakassis and Lampadariou,
unpublished)
Classic trends of each of indices (S, A, B) are documented in the literature and the range of
these indices are site and environment specific. Therefore, it is not appropriate to specify a
range for these indices.
3- List of data / parameters required for computation.
Sampling of sediment using grab or corer, sieving and preservation of samples in the field
along an organic gradient and reference locations. Laboratory taxonomic identification of
samples resulting in abundance and biomass of species (and/or) families.
1
Please return these sheets to the WP 2 leader, BEFORE end of March 2005.
4- Description of scientific meaning, references
Disturbance of macrobenthic community results in recognised changes in these indices.
Primarily, diversity decreases along an increasing organic gradient, with a corresponding
increase in abundance expected. A severely impacted situation may result in abundance
tending to zero (azoic). Biomass changes along an organic gradient are typically more
complex, with peaks in biomass associated with peaks in opportunistic species and a larger
peak in biomass at unimpacted locations.
References:
Karakassis, I., Tsapakis, M., Hatziyanni, E., Papadopoulou, K.N. & Plaiti, W. (2000). Impact
of cage farming of fish on the seabed in three Mediterranean coastal areas. ICES
Journal of Marine Science, 57, 1462-1471.
Levinton, J.S. (1982). Marine Ecology, pp. 87-89. Prentice-Hall Inc., New Jersey, US, ISBN
0-13-556852-8.
Pearson, T.; Rosenberg, R. (1978). Macrobenthic succession in relation to organic enrichment
and pollution of the marine environment. Oceanography and Marine Biology Annual
Review, 16: 229-311.
5- Range of validity; please provide a description of the field of validity for the
indicator, its limits, endpoints. Careful explanations should be given in a table
about the correspondence between the computed values and the impact (from
positive effect, no impact , moderate impact, high impact, unacceptable impact).
Wide field of validity for these indicators, except care is required in using some of the
derived indices when very low species (S) are present. E.g. a low S in itself describes the
state of the benthic community and so eliminates the need for derived indices.
Computed values site/environment specific and so not specified here. In particular, the
indicator species and families identified and tested by Karakassis and Lampadariou in the
Eastern Mediterranean will be environment specific.
There tends to be more examples of aquaculture impacts and these indices in areas with soft
sediments, but the aquaculture industry in some countries is tending to seek more dispersive,
offshore sites. As a result, these indices will need to be robust for assessing aquaculture
impacts in these environments.
6 -Type of aquaculture on which this indicator applies
ALL
7 - Relevant environments for this indicator
MOST (perhaps excluding environments where aquaculture operations situated above
bedrock/coarse sediments where sampling difficult)
8- Quotation. We will need to select the most appropriate indicators to be proposed for
EIA and site selection. Please suggest a quotation for this indicator for the following
criteria (from A, perfectly adequate, to E, not relevant), to help evaluating the
indicator within WP 4. Additional comments are welcome.
 Direct relevance to objectives :
– A – Most of these indicators are well tested and included as standard in assessment of
benthic communities
 Clarity in design : It is important that the selected indicators are defined clearly in
order to avoid confusion in their development or interpretation. – A - Well established

Realistic collection or development costs : Indicators must be practical and realistic,
and their cost of collection and development therefore need to be considered. This
may lead to trade-offs between the information content of various indicators and the
cost of collecting them. – B - Main limitation is the cost of macrobenthic surveys and
subsequent identification to species level. Some information can be gained by
examining the presence of indicator species/families or identifying to a certain level as
shown recently in the MERAMED project (Karakassis and Lampadariou). This can
result in lower costs in identification. A full cost benefit analysis has also been
undertaken by these authors.

High quality and reliability : Indicators, and the information they provide, are only
as good as the data from which they are derived. – A – Well established and tested

Appropriate spatial and temporal scale : Careful thought should be given to the
appropriate spatial and temporal scale of indicators. – A – Well tested along spatial
and temporal gradients

Obvious significance : The meaning and usefulness of the indicator should easily be
understood by stakeholders. They would preferably use the levels of dissolved oxygen,
rather of sulphide concentrations. B – Although these indices give a useful amount of
information regarding disturbance of the benthic community, it is often the case that
stakeholders prefer a single number contained in an index which describes “impact”.
Ideally S, A, B and derived useful indices should always be provided alongside such
an index of impact.
9- Data and models related to this indicator, available for use by WP 4. Please list the
data and models output available at local, national or regional scales for use by ECASA.
They may not correspond to the more theoretical list asked for in §3.
MERAMED project data sets from several Eastern Mediterranean sea bass/bream fish farms
include these indices for assessment of impact. Similarly, numerous data sets collated by
SAMS for assessment of North Atlantic salmonid farms. DEPOMOD model (Cromey et al.
2002) contains relationship between solids flux arising from salmonid fish farms (g solids m-2
bed yr-1) and abundance. MERAMOD model (Cromey et al, unpublished) contains
relationship between solids flux and S, A, B, A/S, H’, indicators species/families for sea
bass/bream farms. These models can predict the response of these indicators to flux from
aquaculture with some confidence.
Cromey, C.J., Nickell, T.D. and Black, K.D. (2002). DEPOMOD - modelling the deposition
and biological effects of waste solids from marine cage farms. Aquaculture, 214, 211239.
10- Suggestions for use by WP 5. Give examples of indicators/aquaculture/environments
which can be field-tested during the course of WP 5.
All environments and aquaculture types can be assessed using these indicators.
0.1 m-2 van Veen grab or corer taking duplicate grabs along an organic gradient with
samples taken at reference stations.
There is a trend in Scottish regulation towards positioning sampling stations on a site
specific basis, rather than using a nominal distance between stations (e.g. 0, 25, 50 m
from cages etc). This new system locates sampling stations, assisted partly by modelling,
close to the boundary of the Allowable Zone of Effect (AZE). This aims to measure
where the zone of effect of the farm ends (along the main axis of current) and is
supplemented with the usual adjacent to cage sampling station. The change in benthic
community between near cage and boundary is of less interest. A second transect
perpendicular with the main axis of current is not required. Such a sampling station
arrangement could be tested in WP5.
This document is intended to be used for internal work on ECASA workpackage. The final
indicator sheet may include a format somewhat different. Please suggest any improvement for
both the content and the form of this document.
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