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.
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.
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).
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.
Related The Marine Detective posts:
- Gumboot chitons spawning
- Super Mom – up to 300 young under her care [blog item on brooding anemones]
Sources:
- A Snail’s Odyssey; Sea Cucumber Reproduction
- Lambert, Philip; Sea Cucumbers of British Columbia, Southeast Alaska and Puget Sound
- RaceRocks.com; Metridium farcimen
The Marine Detective 
9 Responses to “Sea of Love – Broadcast Spawning!”
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
Dear Yvonne, Your response alone made the blog worth writing. Thank you so!
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.
Paul
Edits noted! And thank you!!!
I had no idea about the pellets – how fascinating and what a terrific shot of them coming out – well done Jackie!
So appreciate the feedback dear Paul. It was such an amazing thing to witness.
Absolutely amazing!!
Bruce Livingston Steveston EcoTours 604-377-5964
So great to get the feedback Bruce.
Increases my motivation.
Thank you!
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.