These are Nomura, the biggest jellyfish in the world, which can weigh 200 kilograms, 440 pounds, as big as a sumo wrestler, and 2 metres in diameter
Jellyfish are kept in check by fish, which eat small jellyfish and compete for jellyfish food. Jellyfish feed on fish eggs and larvae, further impacting on fish numbers.
To add insult to injury, nitrogen and phosphorous in run-off cause red phytoplankton blooms, which create low-oxygen dead zones where jellyfish survive, but fish can’t. “You can think of them like a protected area for jellyfish.”