The Canadian

Centre for Environmental Modelling and Chemistry

Mysid Model

Version 1.00 - August 2007

Software Description

The Mysid model is a single organism bioaccumulation model treats the dynamic uptake and loss of an organic contaminant by the opossum shrip (Mysis relicta). The model describes the concentration and fugacity of the mysid as a function of time as the its volume and lipid fraction content changes over its two year life-span. The uptake processes include respiration and food consumption by both pelagic and benthic sources. Clearance occurs by egestion, metabolism, and growth dilution.

This model is useful for estimating the likely extent of bioaccumulation in the mysid, the relative importance of each uptake and loss process, and the effect of daily migration between the water column and sediment on the bioaccumulation in the mysid. The inclusion of mysid in a simple foodweb demonstrates the effects of benthic-pelagic coupling on the entire aquatic food chain.

The results of changes in chemical, mysid, and environment properties may be explored by modifying the input data. Incremental changes in input properties can be used to obtain a sensitivity analysis.

Features of the Mysid model:

Provides a database of chemicals and chemical properties.
Permits temporary additions/changes of chemicals and their properties to a simulation.
Permits permanent additions, changes and deletions of chemicals and their properties to the database.
Provides a database of mysid and environments and mysid and environment properties.
Permits temporary additions/changes of mysid and environments and their properties to a simulation.
Permits permanent additions, changes and deletions of mysid and environments and their properties to the database.
Provides context-sensitive Help.
Displays and prints the Mysid model calculations, as performed by the program.
Allows the printing of help files, calculations, simulation tables, charts, and diagram.
Allows the program results to be saved as comma separated value (csv) files viewable by standard spreadsheet software.

This program was based on the following publications:

Patwa, Z., Christensen, R., Lasenby, D.C., Webster, E., Mackay, D. 2007. An exploration of the role of mysids in benthic-pelagic coupling and biomagnification using a dynamic bioaccumulation model. Environ. Toxicol. Chem. 26 (6): 186-194.

Mackay, D. 2001. "Multimedia Environmental Models: The Fugacity Approach - Second Edition", Lewis Publishers, Boca Raton.

The required input data are:

Chemical Properties:

  • chemical name
  • molar mass
  • data temperature
  • metabolic half-life
  • log Kow
  • Type 1 Chemicals: Henry’s law constant or water solubility and vapour pressure
  • Type 2 Chemicals: organic carbon – water partition coefficient (Koc)

    Properties of the Mysid and Environment:

  • mysid gender
  • initial length (cycle 1)
  • growth rate (cycle 1 and cycle 2)
  • feeding rate (% body volume per day)
  • digestion factor
  • suspended particles: concentration, density, and organic carbon content
  • sediment: density and organic carbon content
  • lipid volume fraction of food in water
  • gut absorption efficiency (water and organic phase)
  • time spend in sediment (%) by juvenile and adult mysid during summer, fall, winter, and spring


  • chemical concentration in water and sediment

    Simulation Time:

  • time step
  • total simulation time

    Model output includes:

  • all input data
  • mysid dimensions as a function of time
  • Z values for all phases
  • concentrations, fugacities, and amounts
  • uptake by respiration and food
  • gut / blood transfers
  • loss through gills (k2), by metabolism, by growth dilution, by egestion
  • D values, fluxes, equivalent flows, half-times, and rate constants for all processes
  • charts for lifetime and daily (during summer, fall, winter and spring of both juvenile and adult phase) results
  • a summary diagram

    Minimum system requirements are an IBM-compatible PC running Windows 98 or XP. This model will not run under Windows NT or 2000.

    Please read the Mysid SOFTWARE LICENSE before downloading the software. Use of the software constitutes your agreement to abide by the terms and conditions set out in the license agreement.

    Bug Report


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    Last updated June 12, 2013.