Join me in the cold, dark, life-sustaining NE Pacific Ocean to discover the great beauty, mystery and fragility hidden there.

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;
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;
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;
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;
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;
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 ?
Giant plumose anemone releasing gametes. Click to enlarge. © 2014 Jackie Hildering;
Male Giant Plumose Anemone spawning.
Spawning Orange Sea Star Solaster sp.

Related The Marine Detective posts:


9 Responses to “Sea of Love – Broadcast Spawning!”

  1. Yvonne Maximchuk

    Jackie, I can hardly read this for crying, how fabulously wonderful you got to be there during this reproductive release, thank you so much for your posts, they are remarkable and fascinating and awe-some, hugs Y

  2. Paul Sim

    Great article. I voted for your calendar but could not undue a couple of likes and exceeded my limit. I would have unchecked the fish in the bottle and the last shot of the orcas.


  3. Paul Sim

    I had no idea about the pellets – how fascinating and what a terrific shot of them coming out – well done Jackie!

  4. Sharon Jones

    Such amazing to be there and get photos and videos of all that spawning. We just finished a shorekeeper survey in White Rock today and found many plumose anemones. Would love to have been able to see the spawning.


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