Ellen,
     I suspect that the possible correlation (if any) you've mentioned
between beach nourishment/re-nourishment activities in Palm Beach
County, Florida and the "plummeting" of the Fighting Conch population at
Peanut Island is just that: correlation (i.e., likely not the cause).
I'll stick my neck out and say:  I feel that the the population decline
is directly related to overcollecting.  I've been visiting Peanut Island
since the mid/late 1970's.  Back then, you'd trip over hundreds
(thousands?) of Fighting Conch as you walked over the sand flats.
    Many times, I've seen many "discriminating" collectors each pull 3-6
specimens off the flats (documenting their variety;  collecting a growth
series, to trade, etc.), while many others pulled buckets full of these
conchs off the island...  and the process repeated itself, I'm sure, on
the many more occasions that I was not there to observe.  This process,
over the many years, has been cumulative and has taken its toll.  Today,
on most weekends, you can walk across the boats beached on the exposed
flats;  each boat brings several people.  Years ago, the island was
undeveloped; today it is highly developed and a major attraction for
tourists and locals. Non-boaters can now catch a water taxi to/from the
island.  These conchs, in shallow waters and exposed at low tides, don't
(didn't!) have a chance.

    I believe that the same process has contributed to the same demise,
in the same general area, for the Brown-lined Paper Bubble (see records
for: Hydatina physis  or  Hydatina vesicaria) and the large Flame Auger
(Terebra taurinus)...   each "collectors items"...    I doubt you'll
find them there any more.

      As for your other question regarding the fauna associated with
beach nourishment sands:  The State of Florida used to require
collection of benthic samples for enumeration of the infauna in both the
"fill site" and "borrow site" (plus control sites for each) for a beach
nourishment project.  Minimal funds were allocated to this effort, and
thus insufficient samples/replicates were taken and the statistical
ability to conduct Before/After/Control/Impact (BACI) analyses was
fruitless.  The effort was thus dropped, and is no longer required by
the state for beach projects. [the focus is now only on sand grain size
& composition  analysis, sand compaction, and sea turtle nesting and
hatching success].
    That said, the State should have accumulated many lists of what
infaunal species were found, for all of these projects, when the benthic
infauna collecting effort was active. This data was collected with
public dollars and should be available.   Searches on
www.MyFlorida.com  as well as the Florida Fish and Wildlife Conservation
Commission site:   http://www.floridaconservation.org/     may provide
links and contact info to Divisions/people who can point you to the data
or provide it to you. Good luck!

Hope that helps,
Paul

------------------------------------------------
Ellen Bulger wrote:

> Howdy folks,
>
> I've been wondering about the effects of beach replenishment on the
> shoreline biota, including our beloved mollusks. Some years back I
> remember reading on the list about how the fighting conch population
> at Peanut Island (I think it was? Peanut Island? Am I nuts?) had
> plummeted after either beach replenishment or the construction of a
> seawall or some sort of thing.
>
> And I've been wondering and wondering about it. What does the addition
> of sand (either from offshore or inland) do to those animals and
> plants living at the edge of sea and land? Doubtlessly countless
> creatures are killed. How fast do they come back? Well, do they come
> back?
>
> What the heck kind of beasties are living there anyway? Where do I
> start looking for this information?
>
> I'm not just interested in the mollusks. I can't help but be
> especially interested in them, but all the life living in those wet
> and damp shifting sands are part of the picture. Things the mollusks
> eat, things that eat the mollusks, things that are eaten by the things
> the mollusks eat and so on.
>
> So many of you folks are more science savvy than me. Anyone know of
> any studies that have been done or have any suggestions about where
> and how to start chipping away at this project?
>
> Thanks,
>
> Ellen

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