Many civilizations depend on the sea for their food. It can be argued that any town, or country with large sea borders rely more on the sea for their food than landlocked countries.
The ancient Egytians would trade with Babylonies and people living in Mediterranean Sea,Sea Sea.
People living near see mostly depend on sea food including fish, crabs and prawns etc.
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Not many sea creatures dare to eat this animal but the most common predator of the jellyfish is the common sea turtles.
Antarctica is a continent and the animals you name are sea animals. They eat their food from the food chain in the Southern Ocean.
Only civilizations with a food surplus built them.
Food
The consumer in the food chain/web that eats the Austalian sea lion would be forced to find other food. If that consumer can't find other food then it would extinct as wel. And so on...
You may be thinking of Antarctic Krill, properly named Euphausia superba.
Herbivores depend on plants for food.
the minoan - apex
Maylan