I see a number of errors in your claim. Fukushima has the potential to be 25 to 30x radio-nucleotide release greater than Chernobyl.
1st item, the single Chernobyl reactor(Unit 4) while somewhat higher power output core, was ~1/2 of combined power rating of the melted Fukushima cores(unit's 1,2,3)
2nd) Chernobyl unit 4 was newly constructed, and it's core burntime was still in it's infancy.. (~2yrs), It may or may not have undergone it's first refueling swap-out (~1/3 of the core). Meanwhile Fukushima involved 30+ year old reactors(Unit's 1,2, and 3), with 3 fully mature cores, upwards of 5 years of burn-time per core near the start of the next refueling cycle (I.E. ~Worse case for radio-nucleotides) .
3rd, Fukushima is far from over. all indications point to a melt through below the plant, into an subterranean river flow, which will end up carrying the contents of those melted cores into the pacific ocean.
3rd) Iodine-131 is still being detected onsite. I.E. fission is still occurring, thus Fukushima is still of moving target. Note: At relatively low neutron flux levels indicate that the fission yield of I-131 will be maximized(~6x greater)
4th) Unlike fallout on land, where isotope mobility is somewhat limited, the Pacific ocean is far more efficient in respect towards bio-concentration of radio isotopes up the food chain.
Be prepared to write off the food chain for Northern Pacific ocean for the next hundred years or so. It's being subjected to equivalent fallout of ALL Atmospheric Nuclear Weapons ever detonated (worldwide 1945-1980) by just this one incident.