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

Posts tagged ‘marine biodiversity’

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

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.

Mating Great White Dorids: Reproduction of nudibranch species is always right-side-to-right-side; attached by structures called “gonophores”. As reciprocal hermaphrodites, both parents become inseminated and lay eggs.

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. đź™‚

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.

Gills retracted.

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.

Same individual as in the first photo in this blog. I asked super sea slug expert, Dave Behrens, about this behaviour years ago and his response was: “I will agree the “rearing” is unusual in this group of dorids. Rearing is common amoung phanerobranch dorids (those that cannot withdraw their gill) . . . Although we will never know for sure, the behavior is thought to be a way for the slug to elevate itself above the substrate in search of chemical clues for its favorite prey.”

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. 

Another perspective on a Great White Dorids astonishing egg mass.
Prowling for sponges, a mate, or both. 🙂
Poor photo (because my camera housing had moisture in it that condensed in front of the lens) BUT this image shows a Great White Dorid laying an egg masss. It’s one of the times I caught a Great White Dorid in the act whereby I could know what the egg masses look like for this species (albeit that there are some closely related species of nudibranch that lay very similar looking egg masses).

All photos taken in Kwakwaka’wakw Territory, NE Vancouver Island ©Jackie Hildering.


What’s At Stake – Images Speaking Louder Than Words

Three minutes of images speaking louder than words . . .

This short slide show of my images testifies to the astonishing marine biodiversity of Northern Vancouver Island and what is put at risk with projects like the Enbridge Northern Gateway Project which would bring super-tanker traffic of toxic bitumen and condensate to B.C.’s fragile coast, and to the waters on which we depend for oxygen, food, buffering of climate change gases, aesthetics and so much more.

I have submitted this slide show for inclusion on “Hope, the Whale”, a 25′ whale sculpture being brought to the Vancouver Enbridge public hearings (January 14 to 18, 2013) “to symbolize the expansive and growing community of people with a vision of an oil-free coast in BC. The sculpture is designed to be a welcoming, collaborative, visual, interactive and peaceful approach to supporting a healthy environment. The whale will amplify our a collective messages of hope and a vision for a healthy ocean, water, land, communities, green economy, cultures and people.” See this link to contribute your message.

For more information, see my testimony to the Joint Review Panel included in my blog item “Super Natural or Super Tanker?” at this link.