Salnity fluctuations stimulates snails breeding attempts

[Pszemol]

I would like to share with you my recent observation...
And ask a question later to who might know the answer :-)

I have a very small, 10g "experimental" tank with one bag
of Southdown sand on the bottom (yes, it is deeeep)...
Inside I have a lot of snails, macroalgae and some rock.

Since the main purpose of this tank is to observe the sand
dwellers like spaghetti and other worms, snails and nothing
super-delicate I do not have any automatic top-off system...
Unfortunately it happens often I neglect my manual top of
routine and I see sometimes evaporation like 1" which makes
big salnity fluctuations in a small tank like this one...

Everytime it happens I see strings of snail eggs on glass,
plants, rocks... everywhere. I have three kinds of snails
and all of them seems to react to salnity increase with eggs.
Some of them ("dark cerith" - Cerithium atratum) glue long
white strings of eggs sacs, others (unidentified black ones)
glue single sacs with eggs in random places of the tank...

The reason I link snail eggs with salnity is that one time
I have observed same snails laying eggs and it was also
the time I went for a week leaving the tank with no top off.

Why would be increased salnity the stimulus for snails??
What do they "think" happens... why are they tempted to
lay eggs, and does it happen in nature? I was thinking
the salnity of the ocean is pretty constant all the time...

[Ross Bagley]

"Pszemol" > writes:

> I was thinking the salnity of the ocean is pretty constant all the
> time...

Actually, salinity in the ocean is not constant, though the swings are
definitely smaller than in your tank. Evaporation and precipitation
can each result in rather substantial salinity changes to surface
seawater.

I wish I could speak with some authority as to how large these were...

Anyway, that's a really cool observation about your snails. I suspect
that Ron Shimek over at reefcentral.org could give you great answers
to your snail questions (since he's a scientist specializing in marine
invertebrates and a fanatic reef aquarist to boot).

If you do head over there, I'd really appreciate it if you could
repost anything you learn back here...

Regards,
Ross

-- Ross Bagley http://rossbagley.com/rba
"Security is mostly a superstition. It does not exist in nature...
Life is either a daring adventure or nothing." -- Helen Keller

[Christ's Soldiers]

In the land of rec.aquaria.marine.reefs, the word of the Lord came
to Ross Bagley and verily he spoke saying:

Good advice, I'm sure Dr Sand can shed some light. I wonder if they
think its a season change (IE rainy season= salinity change etc) and
base their mating seasonally. That would be my Guess, and just a wild
guess at that.


--

-John
Because it makes things difficult to understand.
Why shouldn't I top post?

[Chris \(....\)]

"Christ's Soldiers" > wrote in message
. 1.4...
> In the land of rec.aquaria.marine.reefs, the word of the Lord came
> to Ross Bagley and verily he spoke saying:
>
> Good advice, I'm sure Dr Sand can shed some light. I wonder if they
> think its a season change (IE rainy season= salinity change etc) and
> base their mating seasonally. That would be my Guess, and just a wild
> guess at that.
>
>
> --
>
> -John
> Because it makes things difficult to understand.
> Why shouldn't I top post?

I guess that would make a good science fair project, or biology lesson.