>>>  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.
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           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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