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Chemicals, Lice And Waste from Salmon farms

CLAWS is MTS-CFD's flagship modelling service for marine environmental modelling:

developed by MTS-CFD, CLAWS is a repository of open-source, particle-based models for application in salmon farms in semi-enclosed sea lochs and open sea areas. CLAWS is written in Python and consists of five modules:

1) Hydrodynamics.
2) Bath treatments.
3) Nutrients.
4) Waste.
5) Salmon lice.

A more detailed description of each module, together with example applications, is provided in the Documentation section but may be summarised as follows:

1. Hydrodynamics - Python scripts have been written to allow the user to compare directly modelled and observed data. These data are output in a suitable format to assess how the model data compares against the calibration/validation requirements for hydrodynamic and discharge modelling e.g. the SEPA requirements.

2. Bath treatments - The bath treatment model predicts pesticide dispersion in the marine environment and comparison is made against statutory standards e.g. the SEPA standards for Maximum Allowable Concentration (MAC) and Environmental Quality Standard (EQS). The module can also be used for effluent dispersion.

3. Nutrients - This module calculates the sea area, mean height, volume and flushing time prior to deriving an equilibrium concentration enhancement (ECE) index for soluble nitrogen.

4. Waste - The waste model calculates the flux of particulate organic matter emanating from the salmon farm and its impact on the benthic community. Predictions of the fate of waste material (feed and faeces) for key parameters such as the footprint of the deposition on the sea floor and waste density levels.

5. Salmon Lice - In an integrated hydrodynamic-biological model, virtual particles are released at each farm site and allowed to disperse into the marine environment. Each particle is a “super-individual”, representing a number of salmon lice larvae. The biological effects of salmon lice production, maturity and mortality rates, salinity avoidance, temperature preference and phototactic vertical swimming behaviour (diel migration) are included.

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