The role of migrations in ecosystem simulation
Advanced Search
Select up to three search categories and corresponding keywords using the fields to the right. Refer to the Help section for more detailed instructions.

Search our Collections & Repository

All these words:

For very narrow results

This exact word or phrase:

When looking for a specific result

Any of these words:

Best used for discovery & interchangable words

None of these words:

Recommended to be used in conjunction with other fields



Publication Date Range:


Document Data


Document Type:






Clear All

Query Builder

Query box

Clear All

For additional assistance using the Custom Query please check out our Help Page


The role of migrations in ecosystem simulation

Filetype[PDF-12.27 MB]

Select the Download button to view the document
This document is over 5mb in size and cannot be previewed


  • Personal Author:
  • Description:
    The Dynamical Numerical Marine Ecosystem Simulation (DYNUMES) model is unique in its ability to simulate, in addition to growth, apex predation, inter-species predation and fishery, spatial and temporal biomass distribution fluctuations caused by fish migrations. Two types of fish migration simulations are discussed: seasonal migrations for spawning and foraging and migrations to regions of optimum environmental conditions (optimum temperature). The general formulation of migration simulation is a three-step process. First, migration velocities are calculated for each migrating species. Secondly, the migrating fraction of the biomass is separated from the non-migrating fraction. Finally, gradients in migrating biomass are calculated and the migrated biomass is computed using a finite difference advection equation. Migrations are simulated over a short time period for stability; several migration calculations are performed during each monthly model time step. At the end of each model month, conservation of biomass is enforced and random diffusion is simulated. The specifics of the calculations as they apply to both seasonal and temperature induced migrations are presented and the results are discussed. Migration simulation enhances the realism of ecosystem simulation models. In addition, it provides a means of studying spatial and temporal changes in predation mortality caused by changes in predator-prey overlap, fluctuations in biomass distributions caused by anomalous environmental conditions, and other space and time dependent factors in the ecosystem.
  • Content Notes:
    by Nancy Pola Swan.

    "This report does not constitute a publication and is for information only. All data herein are to be considered provisional"--Cover.

    "June 1983."

    Also available online in PDF format via AFSC and the NOAA Central Library.

    Includes bibliographical references (leaves 28-29).

  • Document Type:
  • Place as Subject:
  • Rights Information:
    Public Domain
  • Compliance:
  • Main Document Checksum:
  • File Type:

You May Also Like

Checkout today's featured content at

Version 3.25