Paul, Ellen, Dick,

Since Paul "stuck his neck out," I thought it only fair to point out that
his over-collecting as a cause is just as much a correlation as Ellen's
beach renourishment.  Both have taken place and shells have disappeared, but
neither is necessarily more of a proven culprit than the other.  Even Dick's
observation of the disappearance of the Donax clam after a beach
renourishment is anecdotal.  He saw it happen, but there is no "proof."  The
elephant in the room is pollution from development that has taken place in
the last few decades and the increase in farm and urban run off.  Species
that could recover from a disruptive event like beach renourishment or over
collecting, do not stand a chance if they must also compete with pollution.
So we have a "pristine" beach that becomes more and more popular,
development follows, increased population and pollution follows, beach
renourishment follows to keep it "looking" nice, and more folks are walking
the beach and collecting.  A complex series of causative agents: none, one,
or all of which may have spelled the end for a given species in a given
area.

I have run across a few studies that can maybe cloud the issue.  In
Victoria, Australia, a study was conducted on adjacent beach areas, one a
popular spot for recreation and fishing and the other a closed military
area.  With one exception, the cataloged species remained the same in
numbers although the average size decreased in the area open to collection.
The one exception was the black nerite Nerita atramentosa, whose numbers
were slightly decreased.  This is also the most visible of the species in
the study area with its habit of remaining above the waterline on rocks.
Maybe the Florida fighting conch is also "too visible" to withstand
collecting pressure.  Other studies show where nerites are collected for
food that the average size is smaller than where they are not collected -
but none were collected until gone.  Even commercial collecting tied to a
species decline, like the California Haliotis, is still complicated by
development and pollution.  By the way, I pretty much view beach
renourishment (what an oxymoron) as pollution.  Dumping sand from offshore
is certainly renourishing nothing but the public's view of a "beach."  It is
very similar to our artificially kept lawns; renourished with mowing,
trimming, fertilizing, and spraying for bugs.

I have seen other studies that show both development and pollution effects
are almost universally devastating to mollusk species.  This is true of the
freshwater species that disappeared in Hawaii after streams were channeled,
redirected, damned, and made livable for housing development as it is for
the species that died off after an oil spill in the Hong Kong harbor.

Seeing buckets of shells being collected is scary; seeing a beach treated
like a backyard lawn is scary; scarier is seeing no shells to collect
because we treat the oceans of the world like a sewer.

Tom Eichhorst in New Mexico, USA

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