Thursday, July 29, 2010

We were lucky to capture about two young giant pacific octopus larvae in one of our night light adventures. Although it looks more like a squid, it is an octopus. As it gets older the mantel becomes rounded and they spend more time on the bottom.

Just to give you some scale, this little guy is about the length of my pinky fingernail. He will live for 3 to 5 years and get to be about 14 ft from arm to arm.

Wednesday, July 28, 2010

More cute worms!

In addition to Owenia there were lots of other larvae in our plankton tows. These are just two of my favorites, although everything looks cute when it's a baby! The top is some sort of polychaete, and the bottom is not technically a worm although it is worm-like.

It is a phoronid, and is most closely related to bryozoans and brachiopods. Their bodies are shaped like worms, although they have a great feathery lophophore which they use to filter water for food, and their anus loops out near their mouth. They also live in tubes, and they can brood their young in it. There are only 20 species of phoronids world wide.

Tuesday, July 27, 2010

Revenge of the epitokes

Another night light at FHL. This time we got the large epitokes, about as long as my forearm. You can see a shrimp trying to break the worm open to get the gametes inside later in the movie.

Sunday, July 25, 2010

Night lighting

One of the way we get larvae is by lowering a light into the water at night. Many animals are photopositive, that is attracted to the light, which helps them maintain their position in the water column and find food.

By lowering the light at night, we create a sharp gradient of light and can attract a lot of animals. Most of them in this video are megalopae (baby crabs) and epitokes. The epitokes are fast, pinkish, and wiggle as they swim, while the megalopae are much bigger and chunkier.

Saturday, July 24, 2010

Friday Harbor

So, I have just gone up to Friday Harbor Laboratories and have been enjoying my immersion in science after quite a long spell without. I am learning all about larval biology, so have been going on field trips to many different sites, like this mudflat pictured above, to look at egg masses and collect larvae.

One of my favorites is this Owenia sp., which is a type of worm that builds tubes out of small sandy particles. This creature has an interesting development, as the juvenile worm develops around the intestine of the larval body. When it is ready to settle, it drops out of the sac where it was developing and eats its old larval body.