[Coral-List] Massive die-off of Ceraesignum (Dendropoma) maximum in Moorea, French Polynesia

Craig W Osenberg osenberg at uga.edu
Wed Jul 22 16:40:12 EDT 2015

Our research team (Tom Frazer, Jeff Shima, Anya Brown, Craig Osenberg) recently observed a mass mortality event in the vermetid gastropod, Cereasignum maximum (previously Dendropoma maximum) in Moorea, French Polynesia.  Over a 2 week period in mid-July, snails went from apparently "normal" (making mucus nets; feeding; opercula located at the edge of the shell apertures) to "lethargic" (snails greatly retracted into their shells, cessation of mucus-net-feeding) to dead (rotting in their shells).   Mortality rates over this 2 week period were upwards of 90-100%.   This has happened at all shallow-water sites we've inspected in Moorea (C. maximum occurs in depths <10m)..  We are working to get obtain data from other islands as well.  We also are collecting samples for histological and molecular analysis with other colleagues.

We are writing to ask that anyone who observes large numbers of non-net-secreting snails or fresh, empty shells of C. maximum to contact us immediately to help us document the temporal and spatial extent of this mass mortality event.  We also are keen to have healthy (whole) specimens and "near-healthy" specimens prior to significant deterioration of their condition to facilitate our ability to identify the putative pathogen(s) responsible for the die-off and/or the way in which the symptoms manifest (at present, we have very few "healthy" or "near-healthy" specimens).

Thanks much,
Craig Osenberg
Odum School of Ecology
University of Georgia
osenberg at UGA.edu<mailto:osenberg at UGA.edu>

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