Greetings all,

More observations and questions about fluctuating
abundance; native islanders in places such as
Guadalcanal, Solomon Islands and Hermit Islands, PNG,
have told me there are specific months of the year
when particular shells are abundant on the reef in
free-diving depths, and in other months they are only
rarely found. For example, I was told that it was the
wrong time of year to find Conus bullatus, but if I
came back in a few months I could get lots. I was told
the same for Cypraea ziczac in Marau Sound. I bought a
nice bag full of ziczacs that were collected there and
I was told there was a two to three week period every
year when they could be found out in bunches in the
day on shallow reef, but the rest of the year they
were rare. I only found one during weeks of snorkeling
and free diving the area. I was also told the best
time of year varies by species. I was specifically
told that some cones come up out of the depths into
shallow water at certain times. I can not confirm the
accuracy of these observations but I believe there
must be some truth to it. Has anyone documented marine
gastropods migrating and congregating for breeding
like the well documented breeding migration of
lobsters? I would be interested to hear of any
scientific observation of this behavior.

John Flynn
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 "Frederick W. Schueler" <[log in to unmask]> wrote:

> >>>  shells are cyclical, so you get lots of one
> species one year and none the next sometimes
>
> >> OK, Peggy,  I'd like to hear more about this
> "cyclical" business.  Is this a generalization, or
> might some shells only breed every other year? --
> Kay Peterson
>
> > It's a generalization, based on field experience.
> For instance, I was shelling this morning on a flat
> that usually has lots of
> Busycon sinistrum (and the clams on which they feed)
> and Triplofusus
> giganteus; today there were very few. I don't know
> if it's
> because of the extended red tide we've had, the warm
> winter, or a
> general cycle.
>
> * the question was, I think, whether these
> variations in abundance are
> due to a cycle with a regular intervals between
> peaks of abundance and
> scarcity, or just irregular fluctuations?
>
> fred.
>
------------------------------------------------------------
>            Bishops Mills Natural History Centre
> Frederick W. Schueler, Aleta Karstad, Jennifer
> Helene Schueler
>       RR#2 Bishops Mills, Ontario, Canada K0G 1T0
>    on the Smiths Falls Limestone Plain 44* 52'N 75*
> 42'W
>      (613)258-3107 <[log in to unmask]>
> http://pinicola.ca
>
------------------------------------------------------------
>
>
>

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