Puget Sound Opalescents

[northwestdiverdan]

Now that spring is well under way I'm seeing Opalescent Nudibranchs more often. I'm often struck by how different our Puget Sound Hermissenda crassicornis are in appearance from those in California. Ours are smaller and perhaps slightly less flamboyant than their southern relatives. Northern Opalescents have cirrata that show a silver stripe. Here's some from Redondo beach in south puget sound.







These nudibranchs were found on a beer bottle at about 45 feet depth. Shot at f22 with dual strobes. Nikon D80 60mm macro lens.

[Kevin Lee]

Hi Dan, thanks for posting your images of H. crassicornis. Perhaps they are "slightly less flamboyant" because they've just imbibed and drained all the beer in the bottle! In my experience, these guys display a wide color variation, even residents in the same region as this page shows:

http://www.diverkevin.com/North-America ... 2935_zRkBB

I suspect the variation is influenced by diet, maturation stage (note the tiny pale guy in your 2nd foto, lower right) and environmental conditions of a particular locale.

Cheers, k;-)

[scottg]

Your Hermissenda's have a nice look, they seem to be more clear, perhaps eating healthier diet up north there!

[Trace]

I have found most, but not all the Hermissendas at La Jolla Shores are lighter and smaller, while most of the ones just a few miles south around Point Loma are usually larger and much more colorful.
Trace

[northwestdiverdan]

I have found most, but not all the Hermissendas at La Jolla Shores are lighter and smaller, while most of the ones just a few miles south around Point Loma are usually larger and much more colorful.
Trace

The color variations are quite interesting....

Here's one from Alaska (Resurrection Bay, near Seward)



One from Puget Sound (San Juan Island)


and one from Southern CA (Channel Islands)


Very different indeed! Some divers in central CA (Monterey) have told me that they find both color types.

[nwscubamom]

I'm glad you brought this up, Dan - I have always wondered the same thing - why are ours up in the Pacific NW so different looking than their California counterparts? I suspect it's diet - that the California ones are feeding on something - maybe the pink coralline algae? - which gives them that really bright coloration. Because check out the last photo, of the one at Whaler's cove that's feeding on the sandy bottom (similar to a lot of habitat we have up here - that nudi is pretty drab and looks like it belongs up in Puget Sound!

Here's one from Puget Sound (Bremerton area):


Down into South Puget Sound (Sunnyside Beach - sandy habitat)


Now way down to Monterey, Lone Cypress Tree:


And lastly, Whaler's Cove at Point Lobos:


- Janna