Urchins: not so FAQ's

[FragIt Dan]

Technical and off topic general discussions on urchins. I am an urchin biologist and will try to monitor this forum for general questions as well, although there are several other very knowledgable people here that I am learning urchin stuff from too!

My first question regarding a comment on another thread...
1) when where and how are urchins used for water testing? What are the used as indicators of?

Dan

 

[Jeremy Blaze]

The omly time I have heard of people using urchins to test water was in the salt mix comparison study, where they were showing that freshly mixed saltwater is toxic.

 

[FragIt Dan]

Paul B made a comment in another thread that made me curious, I think he might know of some examples. It would make sense freshly mixed SW would be toxic to urchins seeing their sensitivity to salinity changes.


Dan Leus

 

[Paul B]

http://www.setac.org/education/resources/SeaUrchinToxicityTestMethods.pdf

this is the common purple urchin that i used to collect in ny by the hundreds.
(sorry, typing with one hand)
i used to sell them to hobbiests for algae problems. purple urchins are not true tropical so when they are placed in a tropical tank, they eat enormous amounts of algae.
i kept them in a chilled styrofoam container and they would eat a head of lettuce in a couple of days

 

[billsreef]

Quite often it's actually the larvae used for bioassay work. Typically the urchins collected are just used as spawning stock to provide those larva.

 

[Paul B]

that is true bill but they have no sence no humor and do croak if there is something wrong with the water. they are also very sensitive to metals.

 

[SushiGirl]

that is true bill but they have no sence no humor and do croak if there is something wrong with the water. they are also very sensitive to metals.

Not sure if I agree with the sense of humor part!

 

[Paul B]

Not sure if I agree with the sense of humor part!

you may be correct, these things live forever in my tank and i have some that i have no idea how old they are.

 

[FragIt Dan]

I just sent a red sea urchin down to a researcher in Oregon that was 183mm. Any guesses on how old it was? I will give you a hint... We can pick up the radioactive signature of the bikini atoll A-bomb testing in it's test and it was already really old when that happened!

 

[TimeConsumer]

I just sent a red sea urchin down to a researcher in Oregon that was 183mm. Any guesses on how old it was? I will give you a hint... We can pick up the radioactive signature of the bikini atoll A-bomb testing in it's test and it was already really old when that happened!

off topic: Which bomb? They detonated quite a few in bikini. I can only assume if you're picking up any signature that it would be from castle bravo. It was a lot bigger and since it was a hydrogen bomb would probably leave a different signature than all the atom bombs detonated over the years.

 

[djedhi]

i recently purchased a tuxedo urchin for my nano tank, and i've been working on my bryopsis problem at the time of introduction. with the treatment of kent tech m, the salinity swing (my fault 1.025 - 1.030) and my snails all died but the urchin survived (continues to stick things to itself, and no lost spikes).

When you say they are sensitive to salinity levels, what is the max swing that would impact their health?

thanks for your time.