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  1. (M) Smokin' Urchin
    by djboccip/ (Dennis J Boccippio) (21 Jan 92)
  2. (M) Smokin' Urchin
    by garyd/ (Gary Dudley) (23 Jan 92)
  3. [M] Observations of Pencil Urchin Spawning
    by kevin/modcomp.uucp (Kevin Smith) (31 Mar 92)

(M) Smokin' Urchin

by djboccip/ (Dennis J Boccippio)
Date: 21 Jan 92
Newsgroup: rec.aquaria

Seeking a bit of net wisdom:

	I have a medium sized (~4" diameter) white 'snowball urchin' (this
is probably a generic shop name; looks pretty urchinlike with about 1/2 - 1
inch spikes, clear tentacle-like motor appendages with two different type
ends, and a ravenous appetite for algae) in a 45 gallon invert tank, water
conditions fine.  Twice since I've gotten him (~ 4 months) I have noticed
that it discharges incredible quantities of a white milky fluid into the
tank, mostly coming out of the upper regions of its test.  The most recent
discharge was enough to cloud the entire tank pretty severely, at least
until the skimmer got going.  Does anyone have any idea what this behaviour
is?  Is it a spawning type reaction?  It doesn't appear to be a stress 
response; the water seems fine and tank conditions haven't changed at all
recently.  Given the amount of fluid lost, I would assume it has to be some
thing reproductive, as it seems an incredibly protein-costly activity.
	Thanx in advance for any advice/experiences/info...

			- Dennis Boccippio
			  Center for Meteorology and Physical Oceanography, MIT

(M) Smokin' Urchin

by garyd/ (Gary Dudley)
Date: 23 Jan 92
Newsgroup: rec.aquaria

Your guess that the "smoking urchin" behavior is reproductive in nature is 
correct.  The white stuff is sperm, so you have a male.  It does cloud the 
water pretty effectively, but I've never seen it lead to trouble even when 
more than one urchin releases at the same time.  Eggs from the females of 
the species I've seen are brownish/redish/orangish in color, and obviously 
grainy, with the consistency (but not the density) of fine sand.

Urchins spawn (in my tanks anyway) every few months, and also whenever 
there is a sudden change (water changes and the like).  Often one will 
start and most of the others in the same tank will follow suit.  Filter
feeding inverts have a feast :-).

I've never seen any small urchins result from this, but I'd be interested 
in hearing from anyone who has, or knows what conditions aid in the 
survival of the embryos and planula(?) (not the adults, I can already keep 
them for several years :-).

                                    Gary Dudley

*                                          508-977-8507 *
* Picturetel Corporation       1 Corporation Way       Peabody, MA 01960 *

	Mostly H20 and whatever pizza and Diet Coke digest into 

[M] Observations of Pencil Urchin Spawning

by kevin/modcomp.uucp (Kevin Smith)
Date: 31 Mar 92
Newsgroup: rec.aquaria

I was doing some "low maintenance" as my wife calls it on my
invert tank when my pencil urchin decided to spawn (or do
the smoking urchin show as I've seen it referred to here).  I've
had this pencil urchin for about 3 years since he was about the 
size of a dime and now he's about an inch (body not including spines).

I probably induced the spawn as I needed to add some freshwater to the
tank and I just added some fresh rainwater, which was probably 10-15
degreees colder than the tank water. (about 70 degerees versus tank of
about 80).  Within several minutes the urchin started spewing out 
white milky clouds for about 10 minutes.  I know this is how some
clam farmers induce their clams to spawn at the right time of the year
is by dipping them or exposing them to colder water for a period of
time but I didn't know urchins might do the same thing?  I assume the eggs 
are let go at the same time but I couldn't see any but they are probably
too small for the naked eye to see.  Does anyone know about how big
pencil urchin eggs are?  

Kevin Smith  !uunet!glsdev!modcomp!kevin

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