Hooked on Tuna - Hackdot

Re:Hooked on Tuna by cubefox on Wednesday November 11, 2026 @04:49AM (#50451499)

There is a lot of phytoplankton, plant-like algae. Though apparently most fish don't eat it directly. Zooplankton (which consumes phytoplankton) seems to be a more common food source for fish. You could call a fish eating zooplankton a "predator" because zooplankton are non-plant algae, but that stretches the definition.

Anyway, tuna don't just eat zooplankton, they eat smaller fish.

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Re:Hooked on Tuna by lexicality on Wednesday November 11, 2026 @01:53PM (#50457038)

I'm not a marine biologist but my understanding is that oceanic food chains are very complex and it's not just orca -> tuna -> sardine -> plankton. Most fish larger than a sardine eat only smaller fish and there's a huge web of various sizes of creature all of which behave in predatory behaviour. Certainly most/all fish large enough to be considered a meal to humans are going to be predators.

I have no idea about biomass ratios, but I'm pretty sure there are more species of fish that eat other fish than not.

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Re:Hooked on Tuna by cubefox on Wednesday November 11, 2026 @03:09PM (#50457983)

Fish mainly eat copepods (a type of zooplankton), which are tiny crustaceans (1-2 mm) carried around by the sea current like algae. Not other fish. Tuna do mainly eat other fish.

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