I've been walking the beach on Mullet Key during the winter low tides since
the early '90's. Seems like every time there is a cold spell, I've found mass
mortalities of certain species that wash up. Obviously here in Tampa, it never
gets cold enough to kill them with a freeze, but what is it that would cause
millions of Anadara transversa like last year to die and become beach drift?
Also last year was the first time hundreds of Macrocallista maculata died and
washed in, but only on one weekend. Then weeks later Tellidora cristada and
Argopecten gibbus, the same week. Then about two weeks later, hundreds of
Raeta plicatella and Dinocardium vanhyningi. The winter before that, thousands
of Ficus communis and heart urchins. All these were fresh dead with the animal
still in the shell, so predation is out.
I have no clue why the "selective" die off happens, but it seems the winter
months only produce this here. I'm not counting any of the storms that have
caused massive beach die offs. I can't see how a two day cold snap could even
be felt under a few feet of water in the gulf, a body of water that size takes
can take days for the temperature to drop even 2 degrees.
 
Scott
Tampa