What effect has all the radiation from Fukushima had on the Pacific Ocean?

There has been quite a lot of destruction of life forms from the radiation. With the oceans being such a gigantic reservoir, there is an appreciable dilution effect, even from a sizeable natural calamity, and there are many types that add significant pollutants to the ocean itself. These are usually locally confined because of this dilution effect. There has to be truly a massive upheaval to wreak havoc in a significant way for a significant percentage of life forms. But that has been the case with Fukushima because of the nature of the pollutant, in this case, deadly radioactivity, so this has caused immediate and long-term effects both. As these radioactive isotopes are absorbed into nature and become part of the food chain of the sea, the damage persists and grows over time. There will be many aberrant ecological changes, much unseen because the ocean is not studied intensively over vast areas due to the huge size, so research tends to be more focused or a more superficial assessment done on a wider basis. So there are many area disasters of this kind that are unappreciated because of the inability and cost of doing widespread and careful monitoring for adverse consequences. But this has been a profound natural, if man-made, disaster.