Thursday, May 27, 2010

Lion's Mane

You know by now that I am the BayWatcher for Save the Harbor / Save the Bay, and that I teach Boston Harbor history and marine science at Boston University.

You probably don't know that I am also an avid fan of Sherlock Holmes - so when I began to get reports of Lion's Mane jellyfish in the Harbor, I was a bit concerned. I had a mental image of primordial monsters, lurking in tidal pools attacking unwary visitors to Boston Harbor this Memorial day weekend - probably inspired by this illustration:
If you recall, Holmes deduced that this fantastic creature was responsible for a mysterious - and agonizing - death in the classic short story by Sir Arthur Conan Doyle "The Lions Mane".

After a couple of calls (to the MWRA's senior scientist Dr. Andrea Rex, and the New England Aquarium's Dr. Billy Spitzer) I concluded that the two small (6-8 inch diameter bell) jellys reported to me - one by a thoughtful and observant ranger in the Harbor Islands National Park, and another by a reliable and experienced marine mechanic with 50 years on the water - were in fact small Lion's Mane jellyfish.

A little research led me to discover that Lion's Mane Jelly's are not that unusual in Mass Bay, though somewhat rare in Boston Harbor in my experience.

In fact, according to the often reliable and extraordinarily convenient Wikipedia, the largest recorded Lion's Mane washed up on shore in Massachusetts Bay in 1870 - and had a bell diameter of 7 feet 6 inches. That's one big jellyfish.

Here's a picture of a smaller one - and a link to the Wikipedia entry on the subject

Lion's Mane do sting, and though they are not particularly toxic - as far as jellyfish stings go - though some people can have a nasty allergic reaction to the Lion's Mane sting.

(If you do get stung, experts advise that you rinse the affected are with water. If you have an allergic reaction seek medical attention, or at least check out

Dr. Rex sent me a link to a great old book Seaside Studies in Natural History written by Elizabeth Agassiz (wife of Louis) and Alexander Agassiz (son of Louis) in 1865 on the marine animals of Massachusetts Bay.

They describe the Cyanea arctica (Lion’s Mane) in detail, including the effect of its sting.

Here's a copy of a really interesting woodcut done by Alexander too, which accompanies the text at Google Books.

Lion's Mane Jelly's have been around for a long time, and given the recent northeast winds and it makes sense that they would make their way into the harbor from time to time - especially if currents are happening to move this way as well.

My advice?

Don't panic if you see one in the water or on the shore - just leave it alone. And don't get into a tide pool with a seven foot jellyfish.

Have a great Memorial Day. See you on Boston Harbor.


PS. Don't forget to check out Save the Harbor's Boston Harbor events and activities page on facebook.


Mom said...

F.Y.I. My name is Carl M. Vining, from Somerville, MA. I am an avid fisherman who does most of his fishing down at the Amelia Earhart Dam in Somerville. While fishing the salt water side on Wednesday, May 26, I encountered two lion's mane jellyfish. One was rather small, the other was about 10-12 inches across. This encounter happened right in front of the locks where the boats come through. In case you want to contact me, my number is 617-666-3184.

Steve said...

Hi Bruce --

It would be great to get your jellyfish reports into our global database at

Best wishes,