Science for Everyone


A Bloom of Jellies Make for an Exciting Morning

Post by Olivia Lukacic, Science Education Intern


This lion's mane is one of three seen this morning ranging from five inches in diameter up to a foot! These jellies are most dangerous to us humans as their stinging cells can leave a harmful rash.

When Bailey, the scallop research intern, got up early to see the sunrise and get a start on processing another spat bag on July 10, 2015 she was in awe of what she saw off of the dock. It seems that overnight a whole bloom of jellies had entered Hurricane Sound. We often see mats of rockweed around our main pier with the flow of tides, but this one brought a high density of jellyfish and other wonders. In this group there were comb jellies, moon jellies, and lion's mane, all of which are routinely found in coastal Maine. But what was stumping us was that these were far and few between to the hundreds of a type of jellies that we had never seen before. These were clear to opaque jellies with a white to pinkish purple cross on their main bell. We determined that these curious jellies are white cross hydromedusa (Staurophora mertensii). Not much is known about them, with their range thought to be worldwide but specifically from the arctic to Rhode Island. A quick row out into the cove showed that these jellies were mainly around the floating rockweed and we think they are moving with a current.

A few of the hundreds of white cross hydromedusa found near the dock this morning. These are pictured with a few scallop spat bags. 

Our bloom of white cross hydromedusa is not a unique occurrence for Maine right now, at least in broad terms of jellies. This spring to summer season has already seen many areas of high density jelly blooms raising concern among the public. Although the lions mane is the only common Maine jelly that could pose health risks to humans, the large quantities of moon and comb jellies are still disconcerting. Jellies are a largely understudied group of marine species in Maine, so finding an answer for these blooms is a challenge. The best hypothesis to explaining the influx of jellies range from a response to overfishing, to oxygen depletion from land runoff, to warming waters. Although this winter was cold in comparison to the past decade or so, cold winters only affect the waters close to shore. In fact the Gulf of Maine is warming much faster than the most other oceans, raising concern in all aspects of fisheries and marine studies. We hope that here on Hurricane and in the greater scientific community we can begin to understand what is happening to our coastal waters and what each new tide brings in. 

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