A trophic level of an organism is its position in a food chain.
Levels are numbered according to how far particular organisms are along the
chain from the primary producers [plants] at level 1, to herbivores (level 2),
to predators (level 3), to carnivores or top carnivores (level 4 or 5).
Fish at higher trophic levels are typically of higher economic value.
Millennium Ecosystem Assessment
Figure 1.3. Decline in Trophic Level of Fisheries Catch Since
Nordisk familjebok (1904–1926),
Español: Nivel trófico
Français: Niveau trophique