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Ephemera

“Something transitory; lasting a day”

Last updated 11/16/2008

A Fistful of Jellies

Nye Beach, Newport, Oregon, 11 July 2008

This has been an unusual year in that very few jellyfish, comb jellies, or by-the-wind sailor hydrozoans (Velella velella) have stranded on Oregon beaches, including Nye Beach. That changed today, with a minor stranding of penicillate jellies (Polyorchis penicillatus). I counted an average of one jelly washed up per 10 meters of swash line.

Last October, I collected some stranded penicillate jellies from the beach. They revived when put in fresh sea water (see photo below). I tried the same thing today, but only one of four jellies showed any sign of life, and that very weakly.

If you look closely, you can see a ring of tiny red eyes at the base of the jellyfish’s bell.. Date of photo 11 July 2008.

Penicillate Jellies Rescued from the Beach, 20 October 2007

What’s Eating You?

~~Bell jellies (Polyorchis sp.)~~ Mystery jellies on Nye Beach

October 15, 2008

When I first saw these small jelllies, about the size of a child’s marbles (ca. 10 mm diameter), I assumed that they were comb jellies (Phylum Ctenophora). Comb jellies are primarily pelagic (opean ocean) drifting carnivores that move by beating rows of fused, hair-like cilia and that catch prey with two long tentacles. They are only distantly related to jelly fish (Phylum Cnidaria).

Look closely at the photo above and you will notice that two of the jellies are clear throughout, while the other three have something orange in them. I’ve never seen this before. Are they food items? Internal parasites? Let’s have a closer look.

The first thing to note is that these are hydromedusan jellies, not ctenophores (they lack the rows of fused, hair-like cilia that comb jellies beat in order to swim). The item inside the jelly on the left looks vaguely shrimp-like. The one on the right looks to me a bit like a jellyfish (note the white angling down and right from the bottom middle of the item, resembling the oral arms of a jellyfish). If you ignore the white, though, both inclusions look very similar. This suggests that they could be food items, or perhaps internal parasites that feed on the jellies’ innards.

Addendum, 19 October 2008:

While exploring the beach with a family from Arcata, California, we found the “comb jelly“ at left that appears to be host to four of the presumed parasites. The four red lines could be the circulatory (blood) system of parasitic crustaceans.

But see below!

Late Breaking News!

I took the jelly home and put it in a container filled with sea water. It immediately began the pulsating swimming movements typical of a jellyfish, not the ciliary beating of a comb jelly. In the photo at right, you can clearly see the flowing tentacles and dark eyespots typical of a penicillate jelly, Polyorchis penicillatus. However, the internal organs are unlike other penicillate jellies I“ve seen (see photos in the previous essay, A Fistful of Jellies, compared with the two immediately below). They are also much smaller than the penicillate jellies I am used to seeing on Nye Beach. Technically, these are hydromedusae, not true jellyfish, which means that they are more closely related to the by-the-wind sailors (sail jellies) that frequently wash up on west coast beaches than they are to the moon and sea nettle jellies that also strand here. David Wrobel, one of the authors of Pacific Coast Pelagic Invertebrates: A Guide to the Common Gelatinous Animals, kindly identified it as a Halimedusa typus, a small (to 16 mm tall) hydromedusa. The four radiating organs with a red line down the middle of each are gonads.

Halimedusa typus, a small (to 16mm tall) hydromedusa. “Originally described from Amphitrite Point, Vancouver Island. Abundant in Humboldt Bay, California. Also known from Bodega Harbor, California, and Yaquina Bay, Oregon.” [Yaquina Bay is immediately adjacent to Nye Beach.] “Nothing seems to be known about the natural history of this coastal medusa.” (Source: Wrobel and Mills, 1998)

I also found the dead jelly at right. It was larger than the Polyorchis (?) Halimedusa jelly pictured above (20 mm diameter vs. 10 mm diameter), and had noticeable thickenings, a bit like the hoops that give a hoop skirt its shape, suggestive of a red-eyed jelly hydromedusan (Scrippsia pacifica). However, it lacks the prominent red eyespots of that species. David Wrobel thinks it may be a Melicertum octocostatum, with reservations due to the poor condition of the specimen and because he is trying to identify it from a photo. Many thanks to Dave for his efforts; he is not responsible for any errors in this page.

According to Wrobel and Mills, Melicertum octocostatum is a small jelly (to 14 mm high) that lacks marginal ocelli (eyespots). “Known principally from the North Atlantic, it also occurs widely in the North Pacific; Friday Harbor and British Columbia in late spring, Sitka, Alaska and Bering Sea in late summer, and central Oregon.” [Newport is in central Oregon.] It is a cold water coastal species, may occur in estuaries (where rivers flow into the ocean), is a relatively weak swimmer, and “may hang upside down.”

Melicertum octocostatum (?), a hydromedusan hydrozoan [i.e., not a true jellyfish (a scyphozoan)]

For further information:

Pacific Coast Pelagic Invertebrates: A Guide to the Common Gelatinous Animals, by David Wrobel and Claudia Mills. Monterey, CA: Sea Challengers and Monterey Bay Aquarium, 1998. See also David’s website, the JelliesZone (http://jellieszone.com/)

			Spontaneous Generation Tiny worms in a rain gauge Newport, Oregon November 14, 2008
At least from the time of Aristotle, people believed that life could spontaneously arise from nonliving matter: rotting meat gave rise to maggots and stored grain gave rise to mice, for example. In a classic set of experiments, Francesco Redi demonstrated in 1668 that maggots develop from fly eggs laid on rotting meat, not from the meat itself (see http://www.kent.k12.wa.us/staff/TimLynch/sci_class/chap01/redi.html for details). With the return of the rainy season in Oregon, I put my rain gauge out in my yard. Following the last two storm systems ( 3 November and 11-12 November), I found clusters of tiny worms wriggling in the bottom of the water-filled gauge, pictured below. They might be be nematomorphans, sometimes called horsehair worms because people used to believe they were spontaneously generated in puddles from horse’s tail hairs. However, adult horsehair worms are supposed to be unsegmented and opaque, whereas these appear to be segmented and translucent.

	Horsehair worms are generally between 100 and 700 mm (4"-28") long, but only 1-3 mm in diameter. Clearly, these are much shorter, in the neighborhood of 25 mm (1") long. The scale in the left photo is 15 mm (~ ³/₅ inch) from arrow point to arrow point. If you know what these worms are, please e-mail me.
Elsie B. Klots, in the New Field Book of Freshwater Life (NY: Putnam, 1966), says of horsehair worms: “The eggs are laid in a long, gelatinous string, which later breaks into pieces an inch or so in length. The miniature worm that emerges from the egg swims about for a short time and then encysts upon the vegetation or debris along the bank, where it is engulfed by certain crustaceans, molluscs or insects (mainly beetles, crickets or grasshoppers) within whose bodies the immature form lives parasitically until mature. “The adults, after leaving the body of these hosts, do not feed. They live in standing or running water, in puddles, tanks or ditches, usually in water up to 8 inches deep. They are most frequently seen in the spring and early summer and then not until later in the fall.”
				Update November 15, 2008
				Yesterday, I emptied the water from my rain gauge onto the lawn. As far as I know, all the worms went with the water. I decided to experiment by refilling the gauge with tap water to see whether any more worms would appear. One did (see accompanying photos), and I collected it. I can't be certain that it is a newly hatched worm, but I think it is.

				Note the transparent integument and apparent segmentation of the body. Compare this to the photos of horsehair worms at http://www.kaweahoaks.com/html/horsehairworms.html and http://en.wikipedia.org/wiki/Nematomorpha.
		References Barnes, Robert D. 1987. Invertebrate Zoology, 5th ed. Philadelphia: Saunders College Publishing. Curtis, Helena, and N. Sue Barnes. 1989. Biology, 5th ed. NY: Worth. Klots, Elsie B. 1966. The New Field Book of Freshwater Life. NY: Putnam. Pennak, Robert W. 1953. Fresh-water Invertebrates of the United States. NY: The Ronald Press.

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