Cast ashore

Spring winds pushed some gelatinous animals on shore yesterday.  Here are some examples, shown in order from the animals we encountered most frequently to those that were less common during a walk on Salmon Creek Beach on 19 March 2021:

 

 

Giant Bell Jelly (Scrippsia pacifica)

 

 

 

By-the-wind Sailor (Velella velella) — most of these were small, only ~5-6 mm long

 

 

 

 

Nectophore of the siphonophore, Hippopodius hippopus

 

 

 

 

Comb jelly, or sea gooseberry (Pleurobrachia bachei)

 

 

 

 

Moon jelly (Aurelia sp.)

 

Local jellies

A few nights ago, I promised to show a few more examples of the gelatinous animals that might wash ashore on local beaches at this time of year.  So...here you go!

Two jellyfish:

 

Pacific Sea Nettle (Chrysaora fuscescens) — note the golden brown color (beware, sea nettles can cause painful stings)

 

Moon Jelly (Aurelia sp.) — note the pale purple color

Now, two different hydromedusae:

 

Giant Bell Jelly (Scrippsia pacifica) — note the red eye spots

 

Aglauropsis aeora — note the faint pink and blue coloration

And the swimming bell of a siphonophore:

 

Probably Praya sp. — note that in this species the "jelly" material retains its form, and overall this swimming bell has a shape somewhat like a large tooth, i.e., squared off at one end and with two pointed tips at the opposite end.

P.S.  I think I've written a little bit about all of these species before, so if you'd like to learn more about them, scroll to the bottom of the NHBH web page and use the "Search This blog" function.

Hometown hydromedusa

Last week, Eric's summer students were sorting through some plankton samples collected in Bodega Bay and Bodega Harbor.  Rachel spotted something different and took a closer look.  We're glad she did, because it turned out to be an interesting hydromedusa:

 

Meet Hydrocoryne bodegensis!  The scientists who first described this species (John Rees, Cadet Hand, and Claudia Mills) named it after Bodega Bay because they collected colonies from one of the Bodega Harbor jetties.  It's always fun to become familiar with local species that have "bodega" in their names!

This hydroid also has a polyp stage that grows attached to the substrate.  The tiny medusae (their bells are only ~1 mm high) develop among the clubbed tentacles of the polyp and then eventually break away to swim in the water column:

 

Modified from Rees, J.T., C. Hand, and C. Mills.  1976.  The life cycle of Hydrocoryne bodegensis, new species (Coelenterata, Hydrozoa) from California, and a comparison with Hydrocoryne miurensis from Japan.  Wasmann Journal of Biology 34: 108-118.

Although I didn't know it at the time, five years ago I photographed what might be this species, with a medusa just about to swim away:

 

Eric captured a short video of the Hydrocoryne bodegensis medusa, so I'm including a video file below.  While watching, note the following:

- 4 long tentacles, with visible (knobby) clusters of nematocysts

 

- each tentacle ends in a prominent rounded cluster of nematocysts (you can locate the end of each tentacle by looking for these rounded tips) 

 - a red ocelli (eye spot) at the base of each tentacle

- dramatic extension and contraction of the tentacles (this is likely a feeding strategy, e.g., increasing surface area to increase likelihood of prey capture)

Hydrocoryne Sanford 2017 from Jackie Sones on Vimeo.

 And one last view of this beautiful medusa with its tentacles extended:

 

P.S.  Thanks, Rachel, for spotting a seldom-seen hometown medusa!

From the "midnight zone"

Well, I have to interrupt "The Cedars Series" briefly.  Eric and I found some unusual hydromedusae washed up on Salmon Creek Beach on 26 April 2015.  While this species might be found offshore, it's rare for them to strand on beaches, so I thought you might want to know about it.

As we walked, we started noticing these bright yellow blobs on sand:

 

The blobs ranged in size from ~2-3 cm across, with most being ~3 cm (1.2 inches).

Each one had 4 long tentacles:

 

We counted at least 50 of these hydromedusae on the beach, and we knew we'd never seen them before.  Many of the jellyfish and hydromedusae that wash up on local beaches are clear or have hints of red, pink, or purple.  This amazing yellow color is unusual and was a clue that this was something different.

Although they were in rough shape after coming through the surf zone, we wanted to take documentary pictures.  I put a few of them in a small aquarium:

 

The upright tentacle position is typical for this group of hydrozoans (Subclass Narcomedusae).  Also note that the tentacles leave about mid-way up the umbrella (rather than from the margin).  Meet Aegina citrea!

A side view highlights the bright yellow stomach pouches along the periphery of the bell:

 

And a view from below shows the mouth opening in the center:

 

I liked this view because it closely matches a diagram prepared by Eschscholz who first described Aegina citrea in 1829:

 

From Mayer, A.G. 1910. Medusae of the World Volume 1: The Hydromedusae. 

Carnegie Institution: Washington, D.C.

So the crazy thing about finding Aegina citrea on a beach is that it's generally known as a bathypelagic species.  The bathypelagic zone is sometimes called the "midnight zone."  It's 1,000-4,000 meters below the ocean surface — that's 3,300-13,000 feet!

It has been windy lately, which can cause the upwelling of deeper water to the surface.  Is that what happened here?  Once again, I don't know the answer, but can only document the observation and consider possible causes.  I'd rather think about Aegina swimming through the depths offshore, but nevertheless it was exciting to learn about an intriguing deep-sea neighbor.

P.S.  To see what Aegina citrea looks like in better condition, check out these pictures from the Monterey Bay Aquarium.  (They call them "lemon jellies.")

Clinging to an eelgrass blade near you

Katie had been seeing these small hydromedusae among the eelgrass (Zostera marina) in Bodega Harbor.  We finally looked at some under the microscope together and believe we identified them as Cladonema californicum. 

There are some amazing things about this species and it has some fun connections to wonderful people and local places, too.

Cladonema californicum was first described by Libbie Hyman in 1947.  To describe the species, she used organisms sent to her that were collected in Tomales Bay (near Dillon Beach) by Frank Pitelka in 1941.

Here are two figures modified from Hyman's paper.  The first shows the most obvious features (that you can identify in the next photo!) and the second highlights the unusual branched tentacles — one branch that ends in a sucker and the other with stinging branches.   

  

Both figures modified from Hyman, L. H.  1947.  Two new hydromedusae from the California Coast.  Trans. Am. Microsc. Soc.  66: 262-268.

Now here's a close-up photo of the living hydromedusae.  Look for all of the parts mentioned above.

 

Can you see how the hydromedusa is using the tentacle branches with suckers to cling to the eelgrass blade?  Many of you are probably used to seeing hydromedusae swimming through the water column (like jellyfish).  This species is unusual in that it has adopted a partially benthic lifestyle.  It holds onto the substrate with adhesive pads and then spreads its stinging tentacles to capture prey (e.g., small crustaceans such as copepods).

The next image highlights the fascinating suckers.  The hydromedusa was crawling to the other side of the eelgrass blade when I took this picture.

 

While watching the hydromedusa, we also observed an interesting behavior.  Occasionally it would draw its stinging tentacles and sucker tentacles into the bell and drag them past the oral tentacles (see next photo). This looked like feeding behavior (like wiping your fingers across your lips), although I'll admit that we didn't actually see the hydromedusa catch any prey and I'd feel more comfortable with more observations to say for sure.

P.S.  Libbie Hyman was one of the most influential invertebrate zoologists in North America.  She single-handedly wrote a six-volume treatise called The Invertebrates between 1940 and 1967.  The format of these books was later adopted by other invertebrate textbooks in use today, and her volumes are still consulted and admired for their depth and comprehensiveness.

Here's a nice photo of Libbie Hyman from the American Museum of Natural History's publication about her:

 

From Libbie Henrietta Hyman: life and contributions.  American Museum Novitates no. 3277 (published in 1999, edited by Judith Winston).

Gelatinous assortment

I always have mixed feelings about finding gelatinous animals washed up on the beach.  They belong in deeper water and it's sad to see them pushed up onto the sand by the surf.  But it's also an opportunity to learn about these animals that we wouldn't otherwise get to see unless we were on a boat or diving under water.  And it's a chance to document which species are present in nearshore waters right now.

Here are a few species washed ashore on Salmon Creek Beach after yesterday's big waves.

Representing the Cnidaria —

 

A large purple Moon Jelly (Aurelia sp.)

and

 

A Giant Bell Jelly (Scrippsia pacifica)

Representing the Ctenophora —

 

A small Sea Gooseberry (Pleurobrachia bachei)

Representing the Mollusca —

 

The gelatinous pseudoconch of the pelagic snail Corolla spectabilis

I've written about all of these species before, so if you'd like to learn more about any of them, click on the appropriate name: Moon Jelly, Giant Bell Jelly, Sea Gooseberry, Corolla spectabilis.

 

Sombrero or Umbrella?

On 28 November 2013, we went for a walk on Doran Beach and noticed these animals washing ashore.  Most of them were ~3 cm (a little over an inch) across.  Viewing them from above, they looked like little suction cups!

 

We picked one up, and this is what it looked like on the tip of Eric's finger:

 

And here's another spread out on my mother's hand:

 

The view above made us laugh and led us to make up a name for this gelatinous animal — the "Sombrero Jelly."  

Note the tiny black dots around the perimeter...the peak in the center with a gray smudge on top...and four radiating beige lines on the flat portion (like spokes on a wheel).  (If the medusa is a clock, the beige lines are at about 2, 4, 8, and 10 o'clock.)

We weren't certain which way was up.  Was the animal right side up, or upside down?  We needed to submerge it in water so it would orient itself.

You'll laugh at me and the next picture, but it's a good lesson in transparent camouflage.  First I tried to place the medusa in a shallow pool of salt water on the beach:

 

Can you see it?  It's there, believe me.  Right in the center of the picture.  If you look very closely for a circular outline and the four radiating spokes, you might be able to find it.  But don't worry if you can't.  As mentioned, it illustrates just how effective it is to be transparent!

Then I remembered that I had a very small plastic container in my backpack.  So I filled it with salt water and placed one of the medusa in the water:

 

Now you can see the animal in its natural position.  They had been washing ashore and we had been holding them upside down!  

It has a shallow domed bell at the top.  The black dots around the perimeter mark the positions of hundreds of short tentacles.  The protuberance hanging down in the center is called a peduncle and there are four frilly lips at the tip of it.  The four beige radiating lines are gonads.  

Not a great picture, but below is one more view looking up into the mouth/lips with the four radiating gonads and the rim of tentacles in the background.

 

I'm not 100% certain, but my best guess for this species right now is a hydromedusa called Eutonina indicans, sometimes called an Umbrella Jelly.  I'll be checking in with a hydromedusa expert to see if she can confirm the identification.

Has anyone else been seeing sombreros or umbrellas washing up on local beaches?  :)

ADDENDUM (6 December 2013): Yes!  Claudia Mills (University of Washington) has confirmed this as an Umbrella Jelly (Eutonina indicans).  Thanks, Claudia!

 

Watch your step!

I haven't had a chance to post these pictures.  About a week ago on 3 November 2013, large numbers of ctenophores or comb jellies were washing ashore at Doran Beach.  The densities were much higher than usual.

 

These are Sea Gooseberries (Pleurobrachia bachei).  Various sizes were represented, but most individuals were ~1-1.5 cm across.

Here are two different views from above:

 

 

Although most of the gelatinous animals in these aggregations were comb jellies, every now and then a hydromedusa would appear.  In the image below, look for the individual that's larger with lots of short tentacles around the rim, and small red dots (barely visible) at the base of the tentacles.

 

The hydromedusa is Polyorchis penicillatus.  To see a picture of one swimming in Tomales Bay last November, click here.

I'm not sure exactly why so many comb jellies and hydromedusae were washing ashore, but it may have been related to strong winds.

P.S.  If you're new to the blog and would like to learn more about Sea Gooseberries, review earlier posts from 15 July 2013 and 19 February 2012.

Gaze into my crystal bell

During a very short walk on 8 September we saw over 20 of these hydromedusae washed up on the outer beach:

 

This individual was ~9 cm across, but most were smaller in diameter.  This is Aequorea sp., sometimes known as the Crystal Jelly.  

Note its transparency and the hundreds of radial canals projecting outward towards the bell margin (see below).  The tentacles are missing, as is the mouth, probably because these medusae were tumbled in the surf.  But it's still a decent example of this distinctive species.

 

Aequorea are famously bioluminescent.  There's a nice description and images showing the bright green points of bioluminescence encircling the bell margin on the Bioluminescence Web Page.

Ready to go

My favorite picture from today:

 

Believe it or not, this hydromedusa originated from a hydroid colony that looked like this:

 

When you zoom in, there are tiny medusae (like the one in the first photo) attached to the polyps within this colony.  In the following image, there are several medusae in various stages of development (some younger, some older).  Can you tell which ones are just about ready to swim away from the polyp?

 

On the lower side of the polyp, there are two younger medusae — they look like little ovals with golden spots at the base.  On the upper side, there are two older medusae, one in the foreground and another in the background — their tentacles are now unfurled.  Both of these older individuals appear poised to take off into the wide, wide ocean very soon.

P.S.  To give you some sense of scale, the entire colony in the second photo was only ~2 cm tall.  The hydromedusa is only ~1 mm long.  All of these pictures are greatly magnified.

Washing in with the waves

This was a working weekend for me, so I didn't have much time for pictures.  But I took a quick walk on the beach late this afternoon and noticed a few interesting gelatinous animals washing in with the waves.

I've come to expect Aglauropsis aeora during calm, warmer water conditions in the summer.  Today the ocean reached 14.5°C (58°F) , so I wasn't surprised to see this beautiful hydromedusa.  These images were taken quickly in a small field aquarium.

 

 

I posted better pictures of this species last August.  To see those and to learn a little more about Aglauropsis, click here.

Interestingly, there were quite a few ctenophores (comb jellies) washing in today.  They looked like sea gooseberries (Pleurobrachia sp.), but I'm not used to seeing them at this time of year.  I wondered if they might be a different species of sea gooseberry than the one we see during the winter/spring? 

For the record, I also saw a few large salps (Thetys vagina) and at least one large Giant Bell Jelly (Scrippsia pacifica).

Jellies in the WGC

Yesterday we sailed over to White Gulch on Tomales Point (northern tip of Point Reyes) for a picnic lunch.  When leaving White Gulch, we encountered fairly high densities of two jellies: a hydromedusa called Polyorchis penicillatus and Moon Jellies (Aurelia sp., probably A. labiata).

Polyorchis is a relatively large hydromedusa — most of the individuals we saw yesterday had bell lengths of ~2-3 cm.  There is red pigment at the base of each tentacle (see below).  (The red coloration is part of the ocelli, or eye spots that are sensitive to light.)

 

The tentacles are highly contractile, short when pulled in (as above) but extending to 2-3 times the length of the bell when "fishing" (next photo).  Polyorchis trolls for zooplankton such as copepods, and may also feed on the bottom while elevated on its tentacles.

 

I had a tough time photographing the Moon Jellies while under sail, but here are a couple of shots for the record.  Most of them were ~10-15 cm across.  Note the hundreds of very fine, thread-like tentacles along the margin.

 

Below you can see the slightly scalloped edge, as well as the four pinkish horseshoe-shaped gonads in the center.

 

These two species may also be seen in Bodega Harbor, so keep an eye out for them if you're on the marina docks or walking the Spud Point breakwater.

P.S.  For fans of Finding Nemo, do you remember when Marlin (Nemo's dad) and Dory are navigating a dense swarm of jellies in the EAC, or East Australian Current?  The concentration of jellies in White Gulch reminded us of this scene, so we started joking that we were sailing through the jellies in the WGC, or White Gulch Current.