Modelling habitat choice in fish using adapted random walk

Authored by Geir Huse

Date Published: 2001

Sponsors: Norwegian Research Council (NRF)

Platforms: No platforms listed

Model Documentation: Other Narrative Mathematical description

Model Code URLs: Model code not found

Abstract

A new concept for modelling habitat choice, called an adapted random walk, is presented. The concept is based on the evolution of threshold values for departures and destinations using a genetic algorithm. A habitat is departed if the fitness value associated with it is below the evolved threshold value. Movement is determined probabilistically using random numbers and adapted threshold values. Different versions of this concept were tested for the ability to model horizontal distribution of the Barents Sea capelin using two different fitness criteria. When adapting both departure and destination thresholds, the model performed better than a neural network model with the same number of adapted variables. The evolved threshold values can be used interchangeably with values estimated in the field, for example preferred temperature ranges or prey abundance. The adapted random walk concept functions intuitively, and can be useful for applied Purposes, such as extending models of fish distribution beyond the advected stages and studying the effects of climate change on the spatial distribution of fish.

Tags

individual-based models behavior Larvae Barents sea