I don't think Fukushima released much strontium (do you have a source otherwise)? The atmospheric release concentrated elements with high vapor pressures, in particular iodine and cesium.
edit: Here's a paper [0] which measured Sr-89 and Sr-90 in seawater near Japan: they found a ratio of about 0.026 of Sr-90 : Cs-137 -- relatively little strontium. Their estimate for total Sr-90 released is 90-900 TBq, corresponding to Cs-137 release estimates of 3.5 - 35 PBq. The figures for Chernobyl [1] are 10 PBq and 85 PBq respectively -- that is, Chernobyl released 10-100 times more Sr-90 than Fukushima. The Sr-90 : Cs-137 ratio was even higher (0.63) for atmospheric weapons tests: 600 PBq Sr-90, 900 PBq Cs-137 [2].
edit: Here's a paper [0] which measured Sr-89 and Sr-90 in seawater near Japan: they found a ratio of about 0.026 of Sr-90 : Cs-137 -- relatively little strontium. Their estimate for total Sr-90 released is 90-900 TBq, corresponding to Cs-137 release estimates of 3.5 - 35 PBq. The figures for Chernobyl [1] are 10 PBq and 85 PBq respectively -- that is, Chernobyl released 10-100 times more Sr-90 than Fukushima. The Sr-90 : Cs-137 ratio was even higher (0.63) for atmospheric weapons tests: 600 PBq Sr-90, 900 PBq Cs-137 [2].
edit2: Made a table:
[0] (pdf) http://www.biogeosciences.net/10/3649/2013/bg-10-3649-2013.p...[1] (large pdf) http://www.unscear.org/docs/reports/2008/11-80076_Report_200... (table 1, page 9)
[2] http://books.google.com/books?id=JLFX6EMPqBkC&pg=PA34