In Fukushima four PWR type reactors (which is just a large metal pot) melted but stayed inside the containment vessels.
In Chernobyl, an RBMK reactor, which is a ginormous slab of graphite, exploded outwards and burned for ten days, releasing mind-boggling amounts of radioactive hot particles into the top layers of the atmosphere, thus contaminating the whole world.
Incomparable.
They were different kinds of disasters, but not incomparable in terms of the scope and reach of damage done to the environment. Chernobyl didn't have the situation of dumping incalculable amounts of radioactive water into the Pacific.
That is a very, very misinformed or misleading statement. Caesium-137 and Strontium-90 have half lives of around 30 years and do get into seafood. There are warnings given out often about radioactive contaminated seafood. That's why Fukushima's radioactive water dumping was such a problem and neighboring countries had issues with it.
Seafood can and does get radioactive contamination and this increases cancer risks in humans that consume it.
Caesium-137 and Strontium-90 are examples. They can get into the seafood chain and very much do increase cancer risks.