Anemones | The Marine Detective

Jelly-dwelling Anemone – ingest me and I will eat your gonads

An anemone species that parasitizes the jellyfish that eat them?! Then they move out, drop off and live on the ocean bottom?! And they can also move Spiderman-like from one jelly host to another?!

Yes! And in all these years this is the first time I THINK I MAY have photographed a Jelly-dwelling Anemone. They are also known as the Twelve-tentacled Parasitic Anemones and are only up to 2 cm across (Peachia quinquecapitata).

Jelly-dwelling Anemone at the stage of its lifecycle where it is NOT parasitic. That happens earlier in their lifecycle, beginning with them being planktonic larvae that get ingested by jellies ©Jackie Hildering.

Oh Nature you are so wildly varied and fabulous! Somehow seeing this remarkable little animal with a wicked lifecycle makes me feel better fortified to cope with the human-inflicted wickedness in the world. I hope it does the same for you. 💙

About Jelly-dwelling Anemones from Hanby and Lamb, Marine Life of the Pacific Northwest:

“After the larva of this anemone is ingested by a jelly, the tables are turned as it begins to feed on the host’s internal organs. Eventually, it transforms into an almost transparent anemone that hangs inside the jelly . . . Ultimately the anemone drops off and assumes a bottom-dwelling existence in a mud/sand habitat . . . “

A Jelly-dwelling Anemone at the stage of its lifecycle where it has fed on the jelly’s internal organs, including the gonads, and could move from one jelly to another. Read on! Photo ©Karolle Wall, karollewall.com

Research by Spaulding published in 1972, reports that in laboratory tests, the larval anemones of this species were endoparasitic for an average of 11 days – feeding on what was in the intestines of the jelly. Then they became ectoparasitic, feeding on the gonads (sex organs) of their host. After an average of 31 days of being ectoparasites they then “had acquired their adult characteristics and dropped off the host medusa to become free-living“.

Jelly-dwelling Anemone on its way between jellyfish host and ocean bottom?
KJ Reed @Leftcoaster via iNaturalist.ca and conditions of the Creative Commons License.

Then there’s this extraordinarily engaging science communication from Dany Burgess for the Washington State Department of Ecology about this species.

Not that I would never say this species, or any other, is a monster 👹. There is nothing for humans to beware when it comes to Jelly-dwelling Anemones. Unless maybe you are living your life on a trajectory where you may get reincarnated as a jellyfish that will have its gonads eaten by this anemone species. If it is possible to sign some humans up for that fate, I currently have a list. You may have the same list.

Beware of cute little monsters:
The jelly-dwelling anemone has a spooky secret . . .
by Dany Burgess

Step aside, Alien. [the northeast Pacific Ocean] has its very own version of this famous parasitic predator, but without the terrifying claws or fangs. Like an eerily adorable child in a horror movie, an innocent-looking exterior hides the sinister intent of this squishy little monster.

Skeletons in the closet
Peachia quinquecapitata sounds like an unassuming name — even charming! But these innocuous anemones have a sordid past, and the road to adulthood is paved with the bodies of those who stood in their way.

Shortly after hatching into the water column, larval Peachia, called planula, are eaten by jellyfish. You’d think this would be the end of the line, but it’s exactly what the baby anemones were hoping for. Instead of getting digested, the planula get comfortable in their hosts’ gastrovascular cavities and help themselves to food particles. Hey, who doesn’t like a safe place to hide, free transportation and a free meal?

Body snatchers
Unfortunately for the hosts, that free meal is just an appetizer. After a few days, the freeloading anemones begin to hunger for the main course — wait for it — the jellyfish’s internal organs. Duhn-duhn-duuuuuuuh! These pint-size parasites start with the reproductive tissue (a single baby Peachia can consume an entire jelly gonad in two days), then move on to other organs for dessert. Yum!

Weird science
This fascinating research on the Peachia life cycle was conducted at Puget Sound’s own Friday Harbor Laboratories, where scientists determined that up to 62% of one host jelly population (Clytia gregaria) was infected with these little leeches each spring. Although the planula may be able to live freely without hosts, when scientists replicated this process in laboratory culture, only the ones that were eaten by jellies survived. An amazing host-swapping behavior was also observed: the anemones were able to fire their stinging cells into new host jellies and make very slow, sticky Spiderman-esque leaps from one bell to the next.

Beg, steal or burrow
After about a month of eating the unlucky jellies from their insides out, the anemones have had their fill. Remember the scene in Alien where the thing bursts out of the guy’s chest? Well, picture something like that, only way less disgusting. Like swollen ticks, the now fat and happy anemones drop off and go on their merry way, settling down on the sea floor and burrowing the long columns of their bodies into the mud.

Not much is known about the fate of the host jellies, but I am guessing that having your organs munched is probably harmful to your health.

Beg, steal or burrow
After about a month of eating the unlucky jellies from their insides out, the anemones have had their fill. Remember the scene in Alien where the thing bursts out of the guy’s chest? Well, picture something like that, only way less disgusting. Like swollen ticks, the now fat and happy anemones drop off and go on their merry way, settling down on the sea floor and burrowing the long columns of their bodies into the mud.

Not much is known about the fate of the host jellies, but I am guessing that having your organs munched is probably harmful to your health.

Homebodies
After spending their childhoods wreaking youthful havoc on other living creatures, Peachia adults assume new peaceful identities as model citizens. Occurring in the shallow subtidal zone of the Pacific Northwest, they spend their time with their 12 tentacles splayed out on the surface, passively waiting for food to drift by. A closer look reveals that their striped pattern is made up of delicate chevrons — very on-trend with the interior decorating crowd.

Living hand to mouth
The taxonomy crowd might appreciate Peachia for a different stand-out feature, called the conchula: a projection near the mouth that functions in feeding, and is unique to this genus. In Peachia quinquecapitata, the conchula is divided into five distinct finger-like lobes, almost like a miniature hand. And I have to hand it to these mini moochers…they definitely get away with biting the hand that feeds them!”

Sources:

Handby and Lamb, Marine Life of the Pacific Northwest
iNaturalist – Twelve-tentacled Parasitic Anemone
Spaulding, J.G., 1972. The life cycle of Peachia quinquecapitata, an anemone parasitic on medusae during its larval development. Biol. Bull. 143 2: 440-453.
Washington Department of Ecology, Beware of cute little monsters: The jelly-dwelling anemone has a spooky secret

*My photos included in this blog are from April 6, 2025 near Port Hardy in the Traditional Territories of the Kwakwa̱ka̱’wakw (the Kwak̕wala-speaking Peoples).*

Babies in Their Tentacles!

Oh the fabulously diverse ways that anemones reproduce! I recently documented another species where the larvae develop in the mother’s tentacles! I have even seen the babies move.

See them?!

Another *Snakelock Anemone with embryos*.

For at least the three anemone species I show here, when the males release sperm into the water column, the females do NOT release their eggs into the water. Instead, fertilization is internal. The embryos are protected as they develop in their mother’s hollow tentacles for around 2 weeks (also in areas known as the pseudospherules). Then, out into the ocean they swim as plankton, via their mother’s mouth.

There are other local anemone species where fertilization is internal too. But the embryos don’t develop in the mother’s tentacles .e.g. Brooding Anemones and Proliferating Anemones. For these species the young are “brooded” in the mother’s digestive cavity and then crawl out of her mouth and are protected under her tentacles.

In many other anemone species, like Plumose Anemones and Painted Anemones, fertilization is external. Both males and females release their gametes into the ocean at around the same time (broadcast spawning). Fertilization happens in the water column and the larvae are plankton until they settle to the ocean bottom.

And then some anemones also have asexual reproductive strategies like budding off offspring; splitting into two; or pedal laceration where a torn piece of the bottom of the anemone can grow into another anemone!

I’ve said it before . . . and you thought human sex lives were interesting. 😉

Snakelock Anemone
Cribrinopsis fernaldi
Described as a distinct species in 1976.
Crown up to 20 cm wide.

There has been considerable reclassification of local anemone species. For this species, the development of the young in the tentacles was described in research from 1976.

“Male Cribrinopsis fernaldi (Fig. 1) in San Juan Islands, Washington release sperm in springtime. The sperm swim or are drawn into the mouths of the females and fertilise the eggs, some of which are still in the gonads, while others are floating freely in the gastrovascular cavity, in the hollow tentacles, and in swellings around the upper outer surface of the body column. Development proceeds within the gastrovascular cavity through gastrulation (3 days) to swimming planula larva (10 days), and then to release of the swimming larvae via the mouth (15 days).”

“Some embryos were removed from the tentacles of the adult on day 1 (early cleavage), and day 7, day 13 (planula), and day 34. These continued their development and metamorphosed and settled at the same time as the larvae which remained in the adult until natural release. It is concluded that the brooding behavior is protective rather than nutritive in function.”

Crimson Anemone
Cribrinopsis rubens
Described as a distinct species in 2019.
Crown up to 10 cm wide.

Before I ever managed to find a member of this species with young developing in the tentacles, I often witnessed the spawning of the males. I realized that it was always only males I saw spawning (I never saw eggs being released).

As referenced above, this species was only described as a new species in 2019 having previously been confused with the Snakelock Anemone. Considering how closely the two species are related, it was expected that they would have similar reproductive strategies.

Below, photos of male Crimson Anemones spawning.

Spotted Pink Anemone
Aulactinia vancouverensis
Described as a distinct species in 2013.
Crown up to 8 cm wide, and as you can see here, not always pink.

*Spotted Pink Anemone female with embryos.*

Sources:

Sanamyan, N.P., Sanamyan, K.E., McDaniel, N. et al. A revision of sea anemones of the genus Cribrinopsis Carlgren, 1921(Actiniaria: Actiniidae) from British Columbia with the description of a new species. Mar Biodiv 49, 1951–1969 (2019).
Sanamyan N, K. Sanamyan, N. McDaniel, 2013. Two new shallow water sea anemones of the family Actiniidae (Cnidaria: Anthozoa: Actiniaria) from British Columbia (NE Pacific).- Invertebrate Zoology, 2013, 10(2): 199-216.
Siebert, A. E., and J. G. Spaulding. “The Taxonomy, Development and Brooding Behavior of the Anemone, Cribrinopsis Fernaldi Sp. Nov.” Biological Bulletin 150, no. 1 (1976): 128–38.
Snail’s Odyssey – Sea anemones & relatives – Reproduction: Sexual

Get Back I Tell You!

Here’s a post about anemone enemies (say that 5 times).

See those really long tentacles extending from the Short Plumose Anemones in the following image? These are “catch tentacles” that can extend to be up to four times longer than the feeding tentacles.

Short Plumose Anemones reach around with these specialized, extendable tentacles and THEY ATTACK if they come in contact with a different species of anemone, or others of the same species who do not have the same DNA (are not their clones).

The tip of the specialized tentacle breaks off and kills the cells in the spot where they touch their anemone enemy. Apparently this can even kill the target anemone. Short Plumose Anemones on the outside of a group of related clones are more likely to use / develop these specialized tentacles.

Short Plumose Anemones AND Giant Plumose Anemones also have nematocysts (stinging cells in their feeding tentacles) AND they have acontia. See following image. These are defensive strands filled with stinging cells that are EJECTED from their mouths or through the anemones’ bodies when threatened or stressed. These threads extend far beyond the anemone and provide longer distance defence than the stinging cells.

None of the stinging cells of local anemone species impact we humans. But how I wish I had some acontia! Yes, I have defence envy. 🙂

From Invertebrates of the Salish Sea: ” Animals on the border of a clone often develop up to 19 “catch tentacles”, which generally occur close to the mouth. These tentacles, which are larger and more opaque than the other tentacles, have special nematocysts and are unusually extensible (they can become up to 12 cm long or more). They probe the area around the anemone. While they do not respond to food, they DO fire when they contact either A. elegantissima [Aggregating Anemone] or another clone of M. senile. When it fires, the tip of the tentacle breaks off and sticks to the victim, which may retract and bend away. Tissue damage can generally later be seen in the stung area, and the attacked individual may even die.”

Image is of Giant Plumose Anemones = *Metridium farcimen* to 1 metre tall. Short Plumose Anemones are *Metridium senile* to only 30 cm tall and their crown is not as lobed. This photo is the image for this month’s WILD Calendar.

Photos taken in Kwakwaka’wakw Territory near Telegraph Cove, ©Jackie Hildering

Red and White

Some red and white for you on Canada Day.

May we celebrate all that is wild, good and free.

May we truly know the privilege of it all.

May we be the neighbours and stewards who are as open-eyed and open-hearted as this land is large.

Photo: Two Rose Anemones touching, different colours, same species.
Aka Fish-Eating Anemone, Urticina piscivora to 30 cm across.

Super Mom! Up to 300 young under her care.

This is a Brooding Anemone (Epiactis lisbethae to 8 cm across).

She may not have a backbone but she’s a Super Mom!

As many as 300 young can be clustered around her in up to 5 rows, benefitting from the protective canopy of her tentacles which contain stinging cells (nematocysts). The offspring remain here until big enough to stand a good chance of surviving on their own. They then crawl toward independence, claiming their own piece of the ocean bottom.

Note: This blog was initially published in 2013. Reposting for Mothers Day 2020.

I am awestruck by this species’ beauty and reproductive strategy. It is also a reminder of how little we know about marine species that the Brooding Anemone was not recognized as a distinct species until fairly recently (1986), and it still so often gets confused with the Proliferating Anemone (Epiactis prolifera).

I share my marine “detectiving” about this species with you to provide a further example of how extraordinary our marine neighbours are and maybe, thereby, help inspire greater conservation efforts.

But yes, the timing of the blog is no accident. It may be that reflection upon an anemone Super Mom stimulates thought about our human mothers – just in time for Mother’s Day.

So here goes . . . bear with me as I build to clarifying the reproduction of our featured species.

Anemones have many reproductive strategies.

For many species, reproduction can be asexual as well as sexual with strategies like budding off offspring; splitting into two; or pedal laceration where a torn piece of the bottom of the anemone can grow into another anemone!

Some species are hermaphrodites with highly diverse ways by which offspring develop into adults.

In species that have separate sexes, many are broadcast spawners where Mom and Dad release their eggs and sperm into the ocean around them. Fertilization and development thereby happens in the water column.

Then, for only some 20 species of the world’s more than 800 kinds of anemone, there are those in which the female captures the males’ sex cells as they drift by and draws them into her digestive cavity to fertilize her eggs. She “broods’ her young.

Some such anemone species are internal brooders. The young develop inside Mom until they hatch and are expelled into the water column as planktonic larvae.

But then there’s Super Mom – the Brooding Anemone (Epiactis lisbethae). She’s an external brooder.

After she has fertilized the eggs inside her digestive cavity with the sperm she has captured, the young develop inside her until they hatch into planktonic larvae. THEN, they swim out of her mouth, settle on her body under the tentacles and grow into little anemones that feed themselves.

When the offspring are big enough to stand a good chance of survival without the protection of Mom’s tentacles, they shuffle away to independence, leaving space for next season’s young.

The brooding anemone’s young are all of the same generation and are therefore all about the same size.

However, there is a second externally brooding anemone species in the eastern North Pacific where you most often see young of different sizes huddled under Mom’s tentacles. This species – the Proliferating Anemone (Epiactis prolifera) is the one that very, very frequently gets confused with the Brooding Anemone.

Proliferating Anemone with young (Epiactis prolifera). Often confused with the Brooding Anemone (Epiactis lisbethae).

I have strived to clarify the many differences between these two externally brooding anemone species in the table below but to summarize: the Proliferating Anemone is smaller and does not have striping all the way down the column; adults are hermaphrodites; breeding happens year round; there are far fewer young clustered under mom’s tentacles; and they start off there as fertilized eggs, not as free-swimming larva.

The main similarity between these two species is and yes, I am going to use a tongue twister here since I believe it is inevitable when discussing anemones: with anemone mothers like these, baby anemones are protected from their anemone enemies!

Now off you go, share some ocean love with a Super Mom!

There are so many human females out there worthy of awe.
Where, were we to consider how many young they have shielded and helped to independence, the number might well be 300 or more.

Click to enlarge. Table summarizing the differences between Brooding and Proliferating Anemones.

Brooding anemone with young (Epiactis lisbethae) - all the same age. ©2016 Jackie Hildering.

long-horizontal-001

Sources:

- Bucklin, A., D. Hedgecock, et al. (1984). Genetic evidence of self-fertilization in the sea anemone Epiactis prolifera. Marine Biology 84(2): 175-182
- Edmands, Suzanne, 1995. Mating systems in the sea anemone genus Epiactis. Marine Biology 123: 723-733
- Encyclopedia of Life – Epiactis lisbethae
- Encyclopedia of Life – Epiactis prolifera
- Fautin, Daphne G and Chia, Fu-Shiang, 1986. Revision of sea anemone genus Epiactis (Coelenterata: Actiniaria) on the Pacific coast of North America, with descriptions of two new brooding species. Canadian Journal of Zoology 64:8 1665-1674
- Sept, Duane; The Beachcombers Guide to Seashore Life in the Pacific Northwest
- Snail’s Odyssey – Anemone asexual reproduction
- Snail’s Odyssey – Anemone sexual reproduction
- Wallawalla.edu Epiactis lisbethae

Sea of Love – Broadcast Spawning!

Most often, divers prefer good visibility. But oh to have the good fortune to happen to be in the water when marine invertebrates are spawning!

I’ll never forget the first time the seas suddenly turned white and these green packets drifted by my mask.

Orange sea cucumber egg pellet — *Egg pellet from an Orange Sea Cucumber*.

I was euphoric that I happened to be in the water when Orange Sea Cucumbers (Cucumaria miniata) and Giant Plumose Anemones (Metridium farcimen) were broadcast spawning. Witnessing the magnitude of this great force that ensures these species will survive is as awe-inspiring as witnessing the annual spawn of herring or salmon.

Female orange sea cucumber about to release an egg pellet. Click to enlarge. © 2014 Jackie Hildering; www.themarinedetective.ca — *Female Orange Sea Cucumber about to release an egg pellet.*

The same female orange sea cucumber 1 minute later, releasing the egg pellet. Click to enlarge. © 2014 Jackie Hildering; www.themarinedetective.ca — *The same female Orange Sea Cucumber 1 minute later, releasing the egg pellet.*

Another spawning male. Orange sea cucumbers can also be this darker colour. Click to enlarge. © 2014 Jackie Hildering; www.themarinedetective.ca — *Spawning male Orange Sea Cucumber. Species can also be this darker, brownish colour.*

During broadcast spawning, invertebrate males and females each release their sex cells into the water column – in astoundingly copious amounts.

You can imagine how many gametes must be released for there to be a chance of fertilization and for enough of the resulting larvae to survive and not to be eaten by the many filter feeders such as barnacles, anemones and sea cucumbers!

Not only was it the male Orange Sea Cucumbers that were making the cloudy with their astounding numbers of gametes. The Giant Plumose Anemones were broadcast spawning too. Males releasing slow, white jets of their sperm and females then releasing their pinker egg masses. (Note that Giant Plumose Anemones can reproduce asexually as well by pedal laceration but broadcast spawning allows for diversity through sexual reproduction).

Spawning giant plumose anemone. Click to enlarge. © 2014 Jackie Hildering; www.themarinedetective.ca — *Spawning male Giant Plumose Anemone.*

*Giant Plumose Anemones spawning. Males release the whiter masses of gametes while the females’ masses of eggs have a pinkish colour. See them here?*

Giant plumose anemone releasing gametes. Click to enlarge. © 2014 Jackie Hildering; www.themarinedetective.ca — *Close-up of a male Plumose Anemone spawning.*

It is of course a good strategy to have males and females living in close proximity and that timing is everything! The spawn must be synchronized. To release sex cells when others of your kind are not doing so, would be a very failed reproductive strategy indeed. Probable cues for spawning are ocean temperature; the number of days/hours of sunlight (cumulative temperature); and/or the presence of a plankton bloom.

Apparently for both Orange Sea Cucumbers and Giant Plumose Anemones, the males are the first to release their gametes, triggering the females to spawn.

Research has also found that, in the case of Orange Sea Cucumbers, females release around 130,000 eggs packaged in buoyant egg pellets. The egg pellets drift to the surface and dissociate into the individual eggs after about 20 minutes. Spawning in Orange Sea Cucumbers most often happens within 1.5 hours after slack low tide which adds to the success by allowing for a greater concentration of sex cells, maximizing the chances of fertilization.

Through these images, I hope I have been able to relay the awe I felt at witnessing this biological marvel that has allowed these species to survive on Earth for thousands of times longer than we humans have walked upright.

*Female Gumboot Chiton spawning. Click this link for video and more information.*

*Giant Plumose Anemones spawning. Males releasing the whiter masses while females’ eggs have a pinkish colour. See the pink egg mass from a female on the right ?*

*Spawning Orange Sea Star* – *Solaster* sp.

Super Mom! Up to 300 young under her care.

This is a Brooding Anemone (Epiactis lisbethae to 8 cm across).

She may not have a backbone but she’s a Super Mom!

As many as 300 young can be clustered around her in up to 5 rows, benefitting from the protective canopy of her tentacles which contain stinging cells (nematocysts). The offspring remain here until big enough to stand a good chance of surviving on their own. They then crawl toward independence, claiming their own piece of the ocean bottom.

Brooding anemone 1