Ecasa Toolbox

Public Environment Management: Assessing potential impacts

This page concerns indicators and models that might be used to assess the potential impact of a proposed new aquaculture site. Folllow the links for further information on the indicators and models incorporated into the ECASA Toolbox.

Regulatory regimes vary betwen countres. In some cases, the developers may be required to to carry out an Environmental Impact Assessment (EIA) for their proposed new farm. In such cases they may already have used appropriate models, or collected site data relevant to indicators. In other cases, it may be you who decides what should be done and your public organization that performs the site study.

Further details of Environmental Impact Assessment can be found at How to make an EIA and the studies made by ECASA are written up in the form of EIAs for most ECASA study sites. In the case of a proposed fin-fish development, it will be desirable to estimate:

  • the extent to which a proposed site is sensitive to pressures from the wastes of farmed fin-fish, using the indicators suggested below;
  • the potential impacts of the wastes from the potential fin-fish farm on both the farm and the water-body scales, using the models listed below.

It is likely that there will be less concern about the proposed development of a farm for bivalve shellfish, unless it is to be located close to a conservation feature (under the Species & Habitats Directive) that might be overgrown by the shellfish, smothered by mussel pseudo-faeces, or harmed by moorings. These are zone A scale issues. However, there will be requirements to ensure good water quality for the farm (under the Shellfish Directive), and to preserve good ecological quality (under the Water Framework Directive). These imply the need to prevent excessive removal of phytoplankton by bivalve filter-feeders, and are issues of carrying capacity on the zone B (water body) scale, as considered on the Planning page.

Indicators of environmental sensitivity to the effects of fin-fish aquaculture

All other things being equal, the ability of sites or water bodies to assimilate, safely, waste from fin-fish farms, can be compared using these indicators. They can be thought of as setting the slope of the graph of state or impact as a function of pressure.

Environment/farm type & species Indicator Category Scale Indicators
(+) : sensitivity increases as indicator increases
(-) : sensitivity decreases as indicator increases
All types of waters/all fin-fish in net-pens Sensitivity A: Farm Minimum current speed (-)
All types of waters/all fin-fish in net-pens Sensitivity A: Farm Water depth (-)
Regions of restricted exchange/all fin-fish in net-pens Sensitivity B: Water Body Exchange rate (-) or Residence time (+) of surface water
Maximum stagnation time for basin deep water (+)

 

Models for the environmental impact of fin-fish aquaculture

These models can be used to estimate the effects of a proposed fin-fish development on the state of the environment. See also: choosing a model.

Model (alphabetical order) Model category: scale and relevance Environment category Fish type for which applicable Tested at ECASA sites:
(Auto)DEPOMOD needs measurements of currents A (farm-scale); sea-bed impact enclosed, and open coastal, mesotidal waters salmon, cod no report available
FjordEnv includes 3-layer hydrodynamic model B:water body; effects on water column Narrow Regions of Restricted Exchange salmon, sea-bream, sea-bass Creran, Vidlin, Cephalonia
KK3D needs measurements of currents A (farm-scale); sea-bed effects Mediterranean open waters sea-bream, sea-bass ? no report available

LESV includes 3-layer hydrodynamic model
B:water body; effects on water column Narrow Regions of Restricted Exchange salmon Creran
MERAMOD needs measurements of currents A (farm-scale); sea-bed effects Mediterranean open waters sea-bream, sea-bass, tuna no report available
MOM needs measurements of currents A (farm-scale); sea-bed and water-column effects enclosed, and open coastal, waters salmon, sea-bass, sea-bream Dalmar, Sounio, Cephalonia, Piran, Porto Ecolo, Bisceglie
TRIMODENA includes LPT - particle tracking, and HYDRO - gridded 3D hydrodynamic model A: farm-scale, and B: water-body; effects on sea-bed Mediterranean open coastal water tuna ? no report available