Jelly Bloom at North Head
Grand Manan Island: July 12, 2015
Mid-July, and there were a tremendous localized bloom of jellies in the harbour at North Head. It didn’t seem to extend very far outside the harbour at that time (it was mostly just dead jellies nearby in Flagg’s Cove), but at North Head the numbers were truly stunning. A few days earlier we had seen some moon jellies (Aurelia sp.), but most of this bloom was the white cross jelly (Staurophora mertensii) accompanied by occasional lion’s mane (Cyanea capillata) and a few large comb jellies (probably Beroe, though I couldn’t get a close look at any of them).
There are many ideas floating around these days about the causes of jelly blooms. Not knowing what was going on in the local environment, I can’t really speculate on the cause of what we saw at Grand Manan; all I can say is that it was a deeply memorable phenomenon.
North Head harbour, viewed from Flagg’s Cove
When viewed in numbers, you can appreciate that Staurophora, though simple, is a remarkably varied creature.
Staurophora beside a large comb jelly (ctenophore) that may be Beroe.
Cyanea capillata, the Lion’s Mane
__________________
__________________
The arrival of the Grand Manan Adventure put an end to our jelly gazing.
The bloom apparently continued through July in the lower Bay of Fundy.
© Graham Young, 2015
Ancient Shore 
Hi Graham
Great to see these jellies!
Dave
Thanks, Dave! I hope your summer has been going well.
Thanks for showing us something we usually don’t get to see. I don’t think our zoo has a jelly…..
Thanks, Sam. And I have never seen this particular jelly in captivity, so it still might be something different for people.
I have spent fifty summers on the west coast of Sweden, which faces the North Sea. Jellies are very abundant here with moon jellies (Aurelia sp.) at about 80%, lion’s mane jellyfish (Cyanea capillata) 9% and blue jellyfish (Cyanea lamarckii) 1 %. Only once, bout fifteen years ago, lots of strange jellyfish with a cross appeared. They looked like envelopes when they folded up. Thanks to you I now know they probably were white cross jellies (Staurophora mertensii) swept over the Atlantic from your neck of the woods – thanks!
Jonas, many thanks for your note. I just looked up the distribution of Staurophora mertensii and apparently it is also a North Sea species, but it tends to occur farther north and in colder water. So perhaps you them during an interval in which cooler northern water was moving into your area?