Is sea mammal morbidity and mortality in Alaska related to Fukushima's radioactive contamination of the ocean?

A blog named "Rachels-Carson of Today" poses this question, as a number of species of sea mammals in Alaska and Russia are experiencing "abnormal mortality events" and morbidity such as skin lesions. An environmental cause is suspected. Is it radioactive contamination from the Fukushima nuclear catastrophe? In her environmental classic Silent Spring -- the title referring to the potential loss of song birds due to the pesticide DDT's severe weakening of song bird eggshells to the point of species extinction -- nearly 50 years ago, Rachel Carson warned about the synergistic effects of hazardous radioactivity and toxic chemicals in the environment.