the whales washed up along a 6 mile stretch of coast near hokato , japan .
experts have dismissed rumours of impending earthquake as unscientific .
the strandings sparked comparisons with the appearance of 50 melon-headed whales six days before the earthquake in 2011 that left 19,000 dead .
officials instead believe the whales may have suffered a parasitic infection while others say the animals may have been attempting to avoid predators .