Quantification of trophic source contribution to diet

How much does each trophic source contribute to total diet?

  
 
Individual diet may change with individual size and age (= ontogenetic change), with season and with region, hence the anwer to this question may depend heavily on how we organize our investigation according to the following three "dimensions":

- Structural dimension
  Do we deal with an individual, with a certain size or age group, with a population or even greater
  units, e.g. "the" species?

- Temporal dimension
  What is our time frame; the actual situation, seasonal, annual, or lifetime?

- Spatial dimension
  What is the area we look at; a small bight, a coastline, an ocean?

Regarding populations, the structural dimension is of particular significance: To avoid bias introduced by ontogenetic changes in diet, the investigated sample must be representative for the population, i.e. it has to reflect the true population size ar age structure.

  
 

Trophic Source Definition
Food Item identification
 Trophic Source Contribution