Bill Karp, Vice-President of ICES Bureau.
'Trophic interactions are all about who eats whom. It's based on this idea of a trophic pyramid, where there are different levels – called trophic levels. The lowest level contains plants, phytoplankton. Then the next level, which is the first level of consumers, contains small animals that eat plants. Then as you get higher and higher you get bigger animals, fish, and marine mammals that are less dependent on plants and more dependent on bigger and bigger animals.
It's important because these interactions amongst animals and plants that are eaten or eat characterize the ecosystem, and we have to try really hard to understand quantitatively what the energy flow is across these different levels and what the mortality is associated with consumption, which then is part of natural mortality, which is an input into stock assessment models, or in a more complex way because of all these interactions into ecosystem models.'