"The early summer invasion appears to be heavier than normal this year, surprising some and distressing others."
"For weeks, Maine’s marine research centers have been flooded with questions about a seeming jellyfish invasion in local waters, primarily Casco Bay. They’ve ranged from the urgent – should I let my kids go in the water, or are they going to get stung? – to expressions of longer-term fears, namely, is this the result of global warming? Ocean acidification in the warming Gulf of Maine? Proof of a hypothesis that we’re headed for an ocean ecosystem clogged by jellies, creatures that cause many beachgoers to shudder in revulsion?
Researchers across the board say they just don’t know what the cause is. It could be climate change, including warmer waters. It could be a depletion of oxygen in coastal waters because of runoff from the land, or some response to overfishing.
Or, the June bloom could be a random explosion of a species that goes as fast as it comes."