Population Dynamics

Species populations are accounted for in each size class. The population is comprised of:

• Survivors from current size class that grow into the next size class
• Survivors from current size class that don't grow

Survivors are the number of individuals that remain in each size class after implementing growth and applying predation, fishing, and natural mortality

Recruits that enter the initial size class are included in the population during the recruitment stage (at the beginning of the year).

Growth

Growth rates are scaled such that a species can only grow into an adjacent size class interval during a model timestep. For example species are NOT permitted to grow from the smallest size class to the largest in a single time step. The model is scaled to the fastest growing fish.

The probability of a species growing from one size class to another size class is a function of:

• growth type (exponential, Von Bertalanfy)
• upper bound of size class interval
• growth parameters (input data)

The number of time steps (within a year) in the model is calculated from:

• growth probabilities
• based on the fastest growing species

Size class intervals

Each species is divided in five size class intervals. The length of each interval is based on life history traits

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