I'm not sure what the greatest plausible number of trophic levels is for a single chain of consumption, probably 7 to terrestrial food chain of 5 (grass mouse.

I'm not sure what the greatest plausible number of trophic levels is for a single chain of consumption, probably 7 to terrestrial food chain of 5 (grass mouse. But on average food chains aren't that long, marine apex predators sit around trophic level 4.5. There can be an impressive degree of niche partitioning in somd marine habitats though! https://academic.oup.com/icesjms/article/55/3/467/655070 https://academic.oup.com/icesjms/article/55/3/467/655070