Great White! Not what you think . . .
Great White!
Not quite what you were expecting?
These are Great White Dorids. Yes, they are a species of nudibranch and the individuals featured here are mating, prowling for sponges AND succeeding in laying their astounding egg masses.
EACH dot you see in the egg masses (photos below) contains 8 to 12 fertilized eggs. They are laid by both parents because it makes a lot of sense to be a hermaphrodite when you are a sea slug and your eggs hatch into the sea. More fertilized eggs = more chances of some young surviving.
Even after so many years, I find the intricacy and diversity of sea slug egg masses something of jaw-dropping wonder. Not such a good thing when you are supposed to hold a regulator in your mouth while diving. 🙂
Scientific name of this species is Doris odhneri. They can be up to 20 cm long and their egg masses can be at least that size too.
Body design is classic for the sub-classification of nudibranchs that is “the dorids”. Those tufts on their hind ends are the gills and the projections on their heads (which all nudibranchs have) are the sensory rhinophores (rhino = nose). It’s how they smell their way around to find mates, food and whatever else is important in their world.
Notice in the next photo how dorid species are able to retract their gills when disturbed by the likes of an annoying underwater photographer.
Amazing too to think of the importance of smell in the sea isn’t it? Why is the individual in the following photo reared up like that? I believe it allows a better position to smell / detect the chemicals of food and/or a mate. Maybe they are even releasing pheromones? Note that is me musing. There is no research I know of to support this.
In featuring this species, the Great White Dorid, you see that not all nudibranch species are super colourful. But they are all super GREAT.
Species is also referenced as the GIANT White Dorid or Snow White Dorid, or White Dorid or White-Knight Nudibranch . . . etc. Known range is from southern Alaska to California but it’s a species I don’t see often where I dive around northeastern Vancouver Island.
All photos taken in Kwakwaka’wakw Territory, NE Vancouver Island ©Jackie Hildering.
The Marine Detective 
10 Responses to “Great White! Not what you think . . .”
Fabulously fascinating as usual Jackie. Incredible detail on enlargement of the photos, especially egg ribbons, thanks so much
Appreciate the feedback so much Yvonne.
Thanks for your careful observations of Nudibranchs (and indeed everything else). They always get my attention when I come across them in the intertidal, but I don’t pay attention to them as you do.
Thanks also for the clarity as in “Note that is me musing. There is no research I know of to support this.” Wouldn’t it be nice if all of us were so careful to distinguish what we observe from what we think?
And I also love that after hundreds of dives you can be so astonished by something you see that you nearly lose your regulator.
Having a sense of the scientific and educational integrity you stand for Mike, I value this so much.
This is just gorgeous! Fashion designers should look at your photos for inspiration. Thank you.
Thank you for another fascinating post Jackie. I never cease to wonder at natures diversity and beauty that I get to glimpse and appreciate through your words and photographs. Having links to your previous related posts is valuable too and often inspires my curiosity which sends me diving (ha,ha!) into additional resources.
Ah Margaret – what motivation, kindness and wit you gift me! Thank you!
Oh Margaret, how I value the connection to you.
I’m trying to make an video assignment on nudibranches for my class and your article really helped me out. Thankyou for the wonderful read!
Thank you so much for letting me know!