Tuesday, April 03, 2012

It's spring in the intertidal zone, too.

We caught the tide on its way out at Boundary Bay. The section we were walking on was still high in the intertidal zone, partly muddy sand, partly stony. At first, it didn't seem that there was much to see, apart from the zillions of Asian mud snails that grazed on the stones and crunched under our feet, no matter how careful we were.

Varied patterns and colours, all the same species.

Seaweeds on a clam shell

While Laurie examined seaweeds, I turned over small stones, looking for crabs or hermits. Instead, I found these:

Assorted critters on the underside of a stone.

The two green circles were new to me. They were slightly raised from the surface of the stone, and felt like firm jelly covered with slime. I found another and cleaned the slime off; the jelly was pale green with a darker green spiral inside.

Egg ribbon in aspic.

What made these? Most ID sites and my books rarely identify the eggs along with the parent, and I certainly had never seen these. I searched through my books, and then Googled. And struck pay dirt almost immediately; a blog (Why had I never seen this one before?) Buzz's Marine Life of the Puget Sound, with a whole page of eggs identified by species. And there in the middle was the spiral of green eggs. The critter that laid them was a polychaete worm.

Most polychaetes broadcast their spawn, but a few lay attached egg masses. Buzz's layer was a solid green, but the one on the first stone I turned was patterned:

Green and brown worm, about 2 inches long.

I have not been able to identify this species. The parapodia (paddle "feet" along the sides) are wide and leafy.
We found several different batches of jellied eggs; creamy, shapeless masses:

Small lump of jelly with cute miniature barnacles.

More jelly, and assorted amphipods, including a pretty spotted green one.

Bending over a shallow tidepool, I saw that the water was alive with teeny-tiny darting things, almost fish-shaped, but not quite, too small and fast to see well, or to catch. The camera worked a bit better than our eyes.

There are two here, highlighted against white shells, another near the upper left corner. 

If you look closely at the full-size photo (click) you can see a squarish body with two or three appendages in front, and two at the back, before the long tail. I don't know what these are.

Most of the snails were the batillaria, but smaller, fatter, ribbed snails were around the cream egg masses. Whether they are the parents or were feeding on the eggs, I don't know, either. So much more to learn, always!

These are all tiny.

And I found no hermit crabs.

(We're talking of setting up the aquarium again. I'll start collecting water and seaweeds next trip.)


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