More on Moon Jellies

 After posting my blog yesterday, I decided to do a little more research on the life cycle of the moon jellies in Puget Sound or elsewhere. I didn't find much in my natural history books, marine life field guides, or on the Internet. So I sent an e-mail to David Jamison, one of the marine biologist who conducts the popular public Pier Peer events at Boston Harbor Marina. (David, you may recall, also wrote weekly column on creatures of Puget Sound for The Olympian.) 

  I asked David what he knew about the summer aggregations of moon jellies. Here is his reply:    

As to the moon jellies, they do tend to gather into groups Budd Inlet every August and Sept which is about when they begin to die off. They also occur in groups in other areas of Puget Sound. This is not a new phenomena as I have seen them do this for over thirty years that I have been in the local area. There can be hundreds to thousands of individuals.

I have not found a satisfactory explanation for the aggregations. Some have said there is a reproductive reason as there are both males and females swimming at the same time, however they breed from the spring through the summer with the young growing in special areas of the swimming bell of the adult till the fall when the young move off to hard surfaces to form a polyp. Others have said it is due to their method of swimming against water flow during the day. Some have implied that they can orient relative to compass directions when they swim.

Thank you David for this satisfying and humbling reply. To think that this "lower" life form--spineless, simple, and seemingly passive--could orient itself to the North, South, East, or West is remarkable given that a large percentage of homo sapiens seem unable to point to the North when asked or navigate their way out of their driveway without a GPS unit! 

How marvelous that these abundant, relatively common, and easy to observe jellyfish still hold mysteries and perhaps the upper hand on methods for finding mates.

NOTE: The next Pier Peer is October 23, from 8-9:30 p.m. These events are very popular; space is limited (isn't it always?) reservations are required. Go to: People for Puget Sound to reserve before it's too late! 

cn u say cnidarian?

   It's much easier to say "jelly fish," but these gelatinous creatures are not fish. They belong to a group of marine invertebrates called cnidarian and pronounced nye-dare-ee-un.

Late last month two species made quite a showing in lower Budd Inlet: the Moon Jellyfish (Aurelia aurita) and the Lion's Mane (Cyanea capillata).

    My friend Marian first alerted me to the Moon Jellies, which appeared in masses called "smacks". She was out rowing with her team in the dory and sent me the beautiful photographs below--taken from her cell phone--and the following note: 

The area they congregated in was about 25' x 25' x 10' deep (conservatively). We hazarded a guess of hundred thousand jellies!!! Wow, what an experience. We just drifted around over them and watched their beautiful movements. I picked up a small one and then a larger one and was amazed at how dense it was. Very heavy for it's size. I expected it to be about as heavy as water, but it was about twice that heavy. Photos were taken with cell phone cameras as we didn't have a real camera with us!

The white rings on top are actually gonads (the sex organs)--immature ones. The "ripe" ones are yellowish pink or violet on female jellies, and yellow, yellow-brown, rose-colored on males. Young jellyfish are called polyps, mature ones, medusa.

Click here

 to see a fabulous short video of the moon jelly life cycle, complete with sound track. I am trying to track down (next blog?) information on the annual appearance of  these smacks in Budd Inlet.

The photo below looks like Monet's impressionistic painting of his water gardens at Giverny.

 The next day, I rowed over to Ellis Cove and saw another type of cnidarian, the Lion's Mane jelly (below). These jellies (also called "sea blubber or sea nettle) were huge--the world's largest jelly fish. They can reach 8 feet in diameter, though in Puget Sound they grow to about 18 inches across. The whitish, opaque bell is divided into lobes from which 150 shaggy tentacles hang; some tentacles on the specimens I saw were about 10 feet long. This jelly is highly toxic and causes severe burning and blistering. Using its much-folded membranous lips and feeding tube snout, it feeds on small fish and crustaceans.  

 In my Audubon guide to the Pacific Coast, the authors note that, "In Sir Arthur Conan Doyles' story 'The Adventures of the Lion's Mane,' Sherlock Holmes solves a homicide caused by contact between the victim and this medusa in a tidepool."