The Information required to build a working multispecies model is extensive. Many models being developed attempt to incorporate as many parameters as possible, but for the most part it is impossible to include every variable. In most cases it is simply a lack of available information (one of the reasons ChesMMAP was started). In others the model just gets too cumbersome to deal with. Below are listed many parameters that might be required for a good multispecies model.

• Population size in total biomass of all animals in the region of study.
• Age structure of the populations
• Predator prey interactions for all species
• Recruitment
• Age defined predator/prey interactions
• Air and water temperature daily/seasonally/ highs/lows/average
• Water quality
• Major climate event impacts (how a species will react and how the event will affect each population)
• Natural Mortality
• Fishing Mortality
• By catch Mortality
• Energetics of each species
• Primary production estimates by season
• Habitat requirements
• Response to environmental change
• Competition between and among species
• Discards (fishery)
• Types and quantities of habitats available in the region
• Growth rates
• Evacuation rates
• Preferred prey types
• Dietary importance of prey
• Nutrient imputs and losses
• Migration
• Immigration
• Emigration
• Seasonal usage of habitats
• Foraging areas
• At Risk Behaior (when a species sugects itself to easier predation i.e during migrations, feeding)
• Selected removal by a fishery (typically a size range is selected)
• Fecundity

Table 2.  Data requirements for four types of multispecies models.  Note that the requirements shown are for model construction only; under ideal conditions a variety of data (e.g., time series of abundance and/or biomass) would also be available for validation of model output.

             
a A minimum of two years of data are needed for MSP models.
b Our list reflects the minimum requirements for EwE; these models contain several additional parameters for which calibration data are highly useful.
c Abundance and individual weights are required to set the initial conditions only. 
d Abbreviations are:  fishery-independent (FI), fishery-dependent (FD), traditional stock assessments (TSA) (e.g. SSVPA). 
e MSVPA models require abundance for “other predators” and “other prey.”
f MSVPA requires this rate for the terminal year and for the oldest age class.  MSBE requires a population estimate only if the present case is to be simulated.
g Residual mortality is natural (non-fishing) mortality due to all sources other than predation.