> One possible explanation is the colder water temperature. Take the
> Humpback Cowry, Cypraea mauritiana Linnaeus, 1758, a common Indo-Pacific
> species. In it's range Hawaii tends to be farthest from the Equator & thus
> has the coolest water temperatures. Organisms tend to take longer to reach
> sexual maturity in cooler temperatures but will often reach larger matured
> sizes in some aquatic species. This is purely speculation as i'm not aware
> of any molluscan studies conducted on temperature vs size ratios outside
> of Abalone farming.
>
>

Similar ideas have been proposed for Bermuda.  Are the large cowries
known to be regularly breeding in Hawaii, as opposed to being larvae
born in warmer areas and carried by currents to Hawaii?  How do
temperatures compare with southern extensions of the Indo-Pacific such
as Easter Island?

Typically mollusks grow more rapidly until they reach sexual maturity,
when they put lots of energy into gametes instead of growth.  If
conditions are unsuitable for sexual maturation (e.g., cool
temperatures, parasitic castration), then the shell may keep growing
larger for longer.  I suppose that situaiton might be considered
platonic.

--
Dr. David Campbell
425 Scientific Collections
University of Alabama
"I think of my happy condition, surrounded by acres of clams"

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