Nature Blog Network

Tuesday, February 26, 2008

A Protocol for Sea Squirt Dissections

Our biology department has been having a lot problems keeping sea urchins alive here in landlocked central PA. Probably mostly from poor keeping, but they seem to be very sensitive to our wide temperature fluctuations (i.e. purple California sea urchins hate PA winters). As a back up we would like to use another organism when our urchins die off, possibly a Ciona species. Does any sea squirt biologists (Jarrett, Miriam?) have a protocol for dissecting gonad our of sea squirts? It is for a development lab. Please leave or a comment or email me (address in top right sidebar).


  1. In our household we only have experience dissecting gonads out of a) fruit flies and b) mice. Sorry...

  2. Do you want to use them for gastrulation studies? I've never spawned them so I don't know how easy/hard it is. But if you just want to dissect them, it's pretty easy - here's a description.

  3. Hey, Solitary ascidians like Ciona are pretty easy to spawn using light/dark cycles in the lab without dissection. I can get you a detailed protocol if you want. The eggs will develop pretty fast into larvae though, and I don't know that you'll have as much luck seeing all the beautiful phases of development that you see in urchins both because of the speed and the yolkiness of the eggs. Maybe someone out there has tried this? I haven't tried-- whenever I do this I'm usually just interested in getting the larvae and not viewing how they got there.

    I've found purple urchins to be pretty hearty and I'm surprised that you are having trouble keeping them at room temp unless your room gets pretty darn cold (or too hot when the heat comes on?).

    I'm not sure that solitary squirts will be any easier to keep than urchins because you have to worry about getting them suspended food-- urchins are much easier to keep from that perspective. I think it would probably be easier to either improve your holding conditions for the urchins, or just order in fresh urchins to do the lab...

  4. What El Jefe said. (Hah, I've got him reading blogs, now!) But, if you want more info, check out

    A Guide to the Larval and Juvenile Stages of Common Long Island Sound Ascidians and Bryozoans
    Stephan G. Bullard and Robert B. Whitlatch

    I think you can get it from Connecticut Sea Grant. Also, talk to Rick. I think he's done something like this with Ciona in past inverts labs.

  5. Can't remember where I saw it, but read recently about someone have trouble with urchins. They realized it was trace amounts of pesticides on the vegetables they were feeding.

  6. Jarrett, good job on getting Jay reading blogs. I wasn't sure if it was you or Emmett lol

    Jay, Thanks alot for you comment. I appreciate you taking the time. With regard to the urchins, from what I understand in conversation with the lab coordinator it seems to be a problem of keeping the urchin warm enough. The teaching labs are in the basement and its lined with poorly insulated windows at counter height. Heat is virtually non-existent in our cold-war era looking building. The three people in my office share a cozy space heater.

    I suggested moving the holding tanks to the actual tables next time so they are away from the windows. Though this several crowds things there with the scopes, dissecting trays, supplies etc.

    They salinity has been well within a tolerable range. She gets them from Bodega Bay actually. I don't remember the man's name who supplies us. My labmate and I managed to keep 3-5 survivors alive for about a little less than 2 weeks in a small tank with hermit crabs and horseshoe crab (other survivors of intro bio labs - our office tank is known as the retirement home for lab critters).

    Another problem has been with the undergraduate help (IMHO), they just aren't keeping on top of things. The lab coordinator has anywhere between 20-50+ sections and TAs to keep track of so she is stretched thin and not able to monitor her help good enough. But like you say, they are pretty hearty, being intertidal.

    I like the idea though initiating the spawning with light/dark cycles. I think the students will get a kick out of that. Unfortunately, they only have lab for 2 hours one day a week here. But I going to have to start rewriting the invertebrate zoology manual soon, so maybe i can include that as a fun exercise and they can then observe deuterostome development and have some larval fun.

    Anonymous, I don't pesticides are an issue here. We really don't feed them since we get them fedex'ed to us from the coast right before we do the exercise. But they do need to keep for the entire week. I think she gets two shipments. One on sat. and the other on wed. morning so they are always fresh.


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