J. Moll. Stud. (2002), 68, 45-53
© The Malacological Society of London
2002
BIOLOGICAL FEATURES OF A BUCCINID WHELK (GASTROPODA, NEOGASTROPODA) AT THE ENDEAVOUR VENTFIELDS OF JUAN DE FUCA RIDGE, NORTHEAST PACIFIC
,1
1
Department of Biology, University of Victoria, PO Box 3020, Victoria,
British Columbia, Canada V8W 3N5;
2
Geochemical and Environmental Research Group, Texas A & M University,
College Station TX 77843, USA;
current address: Dept. of Renewable Resources, University of Alberta, 751
General Services Building, Edmonton, Alberta, Canada T6E 2X1
* corresponding author: tunnshaw{at}uvvm.uvic.ca
The newly described buccinid gastropod Buccinum thermophilum Harasewych & Kantor, 2001 is currently known only at hydrothermal vents of the Endeavour Segment of Juan de Fuca Ridge. Collected specimens from three vents show differences in shell features (colour, erosion, scarring) and size distributions. Such distinctions suggest that this buccinid forms resident, localised populations with limited inter-vent migration. Snail abundance in images taken every 31 hours varied markedly over time but showed no correlation with emerging fluid temperatures. Stomach contents indicate that this buccinid is an active predator and opportunistic scavenger with a broad diet. Substratum use did not differ significantly from availability but short-term, small aggregations occur, perhaps for mating and to exploit patchy prey. Majid crabs are active predators of these snails. Egg masses are similar to those described for other buccinids with over 200 egg-filled sacs in a mass; it was not possible to differentiate food eggs from embryos as all eggs underwent multiple divisions. Size-frequency distribution from the adults and the lack of advanced embryos in summer-collected egg masses provide some evidence of seasonality in reproduction.
(Received 16 January 2001; accepted 5 July 2001)